This Glossary has been compiled by Daniel A. Huard to include helpful terms and their descriptions that should be relevant to the Green Building, Development, Construction, Sustainability and Resiliency worlds.

This Glossary is copyright © 2018 Daniel A. Huard and has relied on the contributions of Green REsource Council of the National Association of REALTORS®

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Abandoned Property
property left behind intentionally and permanently when it appears that the former owner does not intend to come back, pick it up, or use it. One may have abandoned the property of contract rights by not doing what is required by the contract. However, an easement and other land rights are not abandoned property just because of nonuse. Abandoned land is defined as land not being used at the present time but that may have utilities and infrastructure in place.

A component of a solar thermal heating system’s collector which aids in converting radiant heat energy from the sun to heat energy the heat energy transmitted to the electrolyte (or water) due to its heat absorbing and concentrating ability.

Reducing or removing any kind of pollution.

Active Solar Heating
Systems that collect and absorb solar radiation, then transfer the solar heat directly to the interior space or to a storage system, from which the heat is distributed. There are two types of systems: liquid-based systems and air-based systems. If a system cannot provide adequate space heating, an auxiliary or back-up system provides the additional heat. Both air and liquid systems can supplement forced air systems.

Active Solar Power
A solar electric (photovoltaic or “PV”) system, not passive solar design, that converts the sun’s energy into electricity for the home. It is usually done with PV panels installed on the roof.

Active System
In a home, an active system is one that requires mechanical energy to work. Heaters and air conditioners are part of an active HVAC system. The opposite of an active system is a passive system.

Adapted Species Plant
vegetation that is not native to a particular region but that has characteristics that allow it to live in the area. Adapted plants do not pose the same problems as invasive species.

Added Antimicrobial Treatment
a substance added to a product (e.g., paint, flooring) to kill or inhibit the growth of microorganisms. Some products, such as linoleum, exhibit natural antimicrobial properties. Despite current practice, science has not proven that antimicrobial treatments reduce infection transfer in building finishes more effectively than standard cleaning procedures. Also known as added microbial agent. See U.S. EPA factsheet, Consumer Products Treated with Pesticides factsheets/treatart.htm

Any substance that is used to bond one surface to another surface by attachment. Adhesives include adhesive bonding primers.

Adjacent Site
a site having at least a continuous 25% of its boundary bordering parcels that are previously developed sites. Only consider bordering parcels, not intervening rights-of-way. Any fraction of the boundary that borders a water body is excluded from the calculation.

Advanced Framing / Concrete Construction
A construction method (also known as “Optimum Value Engineering” or “OVE”) that uses less material in the framing of a home and can reduce material costs and improve energy efficiency. Concrete construction involves using insulated concrete forms (ICFs) to create durable, efficient homes. The approach decreases the number of breaks in the thermal barrier of the building envelope. It also can save on construction costs because it is fast, especially compared with “stick built” homes.

Aerated Autoclaved Concrete (AAC)
Precast concrete that is cured by steam pressure inside a kiln called autoclave. The material is lighter weight than conventional concrete and has good insulation properties.

Agricultural Bi-products:
Products developed in agriculture but are not a primary product. This is often converted into building materials, such as straw used in wall panels or entire bales used as building blocks.

Agricultural Fibers:
Natural fibers, such as cotton, often used as insulation materials.

Air Quality Standards:
Amount of pollutants approved by predetermined guidelines that are not to be surpassed during a given time in a specific area.

Alternative Daily Cover (ADC)
material other than earthen material placed on the surface of the active face of a municipal solid waste landfill at the end of each operating day to control vectors, fires, odors, blowing litter, and scavenging. Generally these materials must be processed so they do not allow gaps in the exposed landfill face.

Alternative Energy
Alternative energy consists of those sources which are newer and less often used than conventional energy sources like coal and nuclear power.
Examples of alternative energy sources are wind, solar, and geothermal. These alternative energy sources are also examples of clean energy sources.
Building or retrofitting a home to use solar energy for hot water and/or to produce electric power, when combined with strategies to conserve energy, can drastically reduce a home’s ongoing utility bills.

Alternative Fuel
low-polluting, non-gasoline fuels such as electricity, hydrogen, propane, compressed natural gas, liquid natural gas, methanol, and ethanol

Alternative Water Source
non-potable water from other than public utilities, on-site surface sources, and subsurface natural freshwater sources. Examples include graywater, on-site reclaimed water, collected rainwater, captured condensate, and rejected water from reverse osmosis systems (IgCC).

Annual Sunlight Exposure (ASE)
a metric that describes the potential for visual discomfort in interior work environments. It is defined as the percentage of an analysis area that exceeds a specified direct sunlight illuminance level more than a specified number of hours per year.

American National Standards Institute (ANSI), American Society of Heating, Refrigerating and Air-Conditioning Engineers Inc. (ASHRAE), Illuminating Engineering Society of North America (IESNA) Energy Standard for Buildings. A nationally-recognized energy standard for commercial buildings.

An opening for the purpose of admitting light.

something subordinate to another, more important thing; adjunct; accessory.
In building roofing for example would be a built-in, nonstructural portion of a roof system. Examples include skylights, ventilators, mechanical equipment, partitions, and solar energy panels.

Appropriate technologies: Technologies that satisfy basic human needs while minimizing environmental impact. Appropriate technologies help communities be more self-sufficient by using small-scale systems that people can manage directly on a local level. Examples include locally created and decentralized (off-the-grid) renewable energy and farmer’s markets that sell regional, sustainably grown food.

Area Median Income
midpoint in the family-income range for a metropolitan statistical area, the non-metro parts of a region, or local equivalent to either. The figure often is used as a basis to stratify incomes into low, moderate and upper ranges.

a product formulated from multiple materials (e.g., concrete) or a product made up of subcomponents (e.g., a workstation)

Attached Greenhouse
A structure situated on a lower floor (or even below the first floor) and located on a home’s south side can provide passive solar heat to the home. Heat collected by the greenhouse at the lower level rises into the interior of the home by way of convection.

Attendance Boundary
the limits used by school districts to determine what school students attend based on where they live

Attic Fan
A fan typically mounted on the roof to create positive air-flow through an attic that does not rely on wind or require excessive passive venting. It is connected to a thermostat and operates automatically. Such fans offer several advantages. They:
1. Lower upstairs room temperatures by 10º;
2. Lengthen roof life by keeping shingles cooler;
3. Keep attics dry during the winter if they are installed with a humidistat;
4. Saves up to 30% on air-conditioning costs. (Savings vary by region and roof characteristics.)

Automated Dynamic Façade Systems
are daylighting control devices whose position or light transmission level can be automatically changed by a control system to address sunlight penetration or perceived glare in the space. Acceptable automated dynamic façade systems include interior automated window blinds or shades; exterior automated louvers, shades, or blinds; or automatically controlled dynamic glazing. Automated methods of sunlight penetration or perceived glare control do not include manually operated interior or exterior façade shading systems; manually operated dynamic glazing; or fixed exterior overhangs, fins, shades, screens, awnings or louvers whose position on the fenestration cannot be automatically changed or adjusted. Automated dynamic façade systems are allowed to have manual override but must default back to automated operation after a predefined period of no longer than two hours. Dynamic glazing is further defined in ASHRAE Standard 90.1 and the International Energy Conservation Code (IECC).

Average LED intensity (ALI)
the illumination output for light-emitting diode lamps, as specified in the International Commission on Illumination Standard 127–2007

An instrument, with a capture hood, that measures airflow from a mounted ventilation distribution diffuser.

Base Building
materials and products that make up the building or are permanently and semi-permanently installed in the project (e.g., flooring, casework, wall coverings)

Baseline Building Performance
the annual energy cost for a building design, used as a baseline for comparison with above-standard design

Baseline Condition(s)
before the LEED project was initiated, but not necessarily before any development or disturbance took place. Baseline conditions describe the state of the project site on the date the developer acquired rights to a majority of its buildable land through purchase or option to purchase.

Baseline Water Consumption
a calculated projection of building water use assuming code-compliant fixtures and fittings with no additional savings compared with the design case or actual water meter data

Basis of Design (BOD)
the information necessary to accomplish the owner’s project requirements, including system descriptions, indoor environmental quality criteria, design assumptions, and references to applicable codes, standards, regulations, and guidelines

Bicycle Network
a continuous network consisting of any combination of the following 1) off street bicycle paths or trails at least 8 feet (2.5 meters) wide for a two-way path and at least 5 feet (1.5 meters) wide for a one-way path 2) physically designated on-street bicycle lanes at least 5 feet (1.5 meters) wide 3) streets designed for a target speed of 25 mph (40 km/h) or less. Ensure that you read the current applicable requirements of the relevant Certification that your project is seeking.

Bicycling Distance
the distance that a bicyclist must travel between origins and destinations, the entirety of which must be on a bicycle network.

Bio-Based Material
commercial or industrial products (other than food or feed) that are composed in whole, or in significant part, of biological products, renewable agricultural materials (including plant, animal, and marine materials), or forestry materials. For the purposes of LEED, this excludes leather and other animal hides.

A material that is capable of decomposing naturally within a short amount of time.

A process that uses biological organisms to clean up contaminated water or soil; often used in oil-spill cleanup.

A landscape element, often a planted strip along a street or parking lot, for the purpose of capturing surface water runoff and filtering out silt and pollution before the storm water enters the drainage system or groundwater.

wastewater containing urine or fecal matter that should be discharged to the sanitary drainage system of the building or premises in accordance with the International Plumbing Code. Wastewater from kitchen sinks (sometimes differentiated by the use of a garbage disposal), showers, or bathtubs is considered blackwater under some state or local codes.

Block Length
the distance along a community block face; specifically, the distance from an intersecting Right-of-Way(ROW) edge along a block face, when that face is adjacent to a qualifying circulation network segment, to the next ROW edge intersecting that block face, except for intersecting alley ROWs.

the removal of makeup water from a cooling tower or evaporative condenser recirculation system to reduce concentrations of dissolved solids

Blower Door
A test that measures the air tightness of a building.

Abandoned, idle or underused industrial or commercial buildings where expansion or development is complicated by real or perceived environmental contamination.

BTU is an acronym for British Thermal Unit”. It refers specifically to the amount of energy needed to change the temperature of a pound of water by one degree Fahrenheit. This is the measure of power for many areas pertaining to home energy, including power, heating, and air conditioning.

BUG rating
a luminaire classification system that classifies luminaires in terms of backlight (B), uplight (U), and glare (G) (taken from IES/IDA Model Lighting Ordinance). BUG ratings supersede the former cutoff ratings.

Building Code
A building code is a set of minimum standards for building requirements, often pertaining to structural and fire safety. Building codes are generally set at the state level. Building codes help ensure that all construction meets an agreed-upon minimum standard of safety and comfort.
The term “building code” as it is commonly used rarely, if ever, pertains to green building issues nor to standards higher than minimum required.

Building Envelope
The separation between the interior and exterior environment of a building. Usually consisting of the roof, doors, windows, foundation, and walls.

Building Exterior
a structure’s primary and secondary weatherproofing system, including waterproofing membranes and air- and water-resistant barrier materials, and all building elements outside that system

Building Interior
everything inside a structure’s weatherproofing membrane

Buildable Land
the portion of the site where construction can occur, including land voluntarily set aside and not constructed on. When used in density calculations, buildable land excludes public rights-of-way and land excluded from development by codified law.

Building Science
Building science is the term applied to facts and theories of science pertaining to the construction and performance of buildings. The study of how a building’s systems function together under various environmental conditions in an attempt to achieve an ideal balance of comfort, health and safety. It is important to have a clear understand of building science in order to build high-performance, green, LEED Certified, Green Globes Certified, Living Building Challenge, Passive House-certified, sustainable buildings.  ASHRAE Audits serve an applied Building Science function in their assessment of heating and cooling systems, energy efficiency, ventilation and humidity control.

Built Environment
The man-made creation of, or alterations to, a specific area, including the environment where those changes are made. On a home site, this includes everything that has been disturbed during construction.

Built Green
A green building program in Washington state.

Bus Rapid Transit
an enhanced bus system that operates on exclusive bus lanes or other transit rights-of-way. The system is designed to combine the flexibility of buses with the efficiency of rail.

Carbon Dioxide (CO2)
The most prevalent of the greenhouse gases. Emitted by burning fossil fuels. Naturally occurring from sources such as human and animal respiration, ocean-atmosphere exchange, and volcanic eruptions.

Carbon Footprint
A calculation of the amount of greenhouse gases produced as a result of commercial, industrial, and individual activities. According to the EPA, “many of our daily activities – such as using electricity, using hot water, heating and cooling a home, driving a car, or disposing of waste – cause greenhouse gas emissions.”  The total of these emissions for an individual, household, organization, or company is known as its carbon footprint.

Carbon Offset
A system intended to equalize carbon production around the globe by trading greenhouse gas emissions–typically produced through fossil fuel consumption–for environmentally friendly actions, such as planting trees and using clean energy sources.

Ceiling Fan(s)
Fans, set to push warm air into living spaces, can reduce winter heating bills, and they can cut cooling costs when they are used in lieu of air conditioners.

A fibrous part of plants used to manufacture paper/textiles.

Cellulose Insulation
Insulation is made from recycled newspaper with borates to provide fire protection.

Cellulose Insulation – Post Consumer Recycled Content
Plant fiber that is used in wall and roof cavities to separate the inside and outside of the building thermally and acoustically. Typical materials used to manufacture the product include old newspapers, and telephone directories and borates and ammonium sulfate are included to retard fire and pests. Four major types of loose-fill cellulose products have been developed under a variety of brand names and are generally characterized as dry cellulose, spray applied cellulose, stabilized cellulose and low dust cellulose.

Central Vacuum System
Network of tubing with inlets throughout the house designed to remove debris to an out of the way receptacle. A central vacuum system is more efficient at the removal of dust and debris than traditional vacuums.

Certified Forest Product
A product certified as sustainable/suitable for use in a green building. These products are from a managed forest that has passed guidelines for responsible harvesting and environmental conservation.

Chain of Custody (CoC)
a procedure that tracks a product from the point of harvest or extraction to its end use, including all successive stages of processing, transformation, manufacturing, and distribution

Chain-of-custody Certification
A product that has met certain requirements throughout its life, beginning from its extraction and production all the way to its distribution and sale.

an intensive, multiparty collaborative session workshop that brings people from the project team’s different disciplines and backgrounds together to discuss, explore, generate, and collaboratively produce various design options related to all aspects the project’s development, goals and objectives.

ChloroFluoroCarbon (CFC)-based refrigerant
a fluid, containing hydrocarbons, that absorbs heat from a reservoir at low temperatures and rejects heat at higher temperatures. When emitted into the atmosphere, CFCs cause depletion of the stratospheric ozone layer.

Chemicals used in refrigeration, air conditioning, insulation, or as solvents and aerosol propellants. CFC’s are not eliminated in the lower atmosphere, and therefore they float into the upper atmosphere where their components deplete and destroy the stratospheric ozone layer.

CIR (Credit Interpretation Requests/Rulings)
A request specific to a Registered LEED Project seeking LEED Certification presented to Green Business Certification Inc. for the clarification project team’s proposed method for compliance attainment of a specific LEED credit(s) the project team may have question(s) about the path for attainment of. The CIRs are submitted via the interactive leedonline platform for the Review Team to assess at times with the assistance of the LEED Technical Advisory Group and at times the LEED Technical Committee as well.

Circulation Loop
A system that loops cold water back to the water heater (instead of down the drain) until hot water reaches the faucet. This is the primary component of a structured plumbing system.

Circulation Network (transportation)
all motorized, non-motorized, and mixed-mode travel ways permanently accessible to the public, not including driveways, parking lots, highway access ramps, and rights-of-way exclusively dedicated to rail. It is measured in linear feet.

Civil Twilight
the point in time in the morning (dawn) or evening (dusk) when the center of the sun is geometrically 6 degrees below the horizon. Under good weather conditions, civil twilight is the best time to distinguish terrestrial objects clearly. Before civil twilight in the morning and after civil twilight in the evening, artificial illumination normally is required to carry on ordinary outdoor activities.

Classroom or Core Learning Space
a space that is regularly occupied and used for educational activities. In such space, the primary functions are teaching and learning, and good speech communication is critical to students’ academic achievement. (Adapted from ANSI S12.60)

Clean Energy
Clean Energy is the term for sources of energy created from renewable sources with low environmental impact that do not emit pollution in order to produce that energy. Geothermal, solar, hydro, and wind are all clean energy sources.

Clean Waste
nonhazardous materials left over from construction and demolition. Clean waste excludes typical building contaminants including lead and asbestos.

Clear Glazing
glass that is transparent and allows a view through the fenestration unit or assembly. In contrast diffused glazing allows daylighting yet distorts the view.

Climate Change
Also called climate destabilization or greenhouse effect, this term represents the adverse effects of greenhouse gasses on long term weather patterns.

Closed Cell (spray) Foam insulation (ccf)
Closed Cell (spray) Foam (ccf) insulation is a very efficient type of insulation that also acts as a moisture and air barrier but which is more expensive than traditional types of insulation. Sometimes a small amount of ccf is used in combination with other insulation to get the most cost-efficient energy-efficient insulation in a given space.

Closed-Loop Cooling
a system that acts as a heat sink for heat-rejecting building and medical equipment heat by recirculating water or other electrolyte. Because the water or other electrolyte is sealed within the system, some closed-loop cooling systems use nonpotable water (such as recycled process water harvested from an air handler’s cooling coil condensate).

Closed Combustion
A design for combustion equipment (e.g. furnaces, water heaters) in which the air provided to the combustion equipment is ducted from the outside, and all exhaust gases are ducted directly to the outdoors. All elements of the system are sealed to prevent leakage of combustion exhaust into the home.

Coheat Test
A test that measures the distribution of heating and cooling systems throughout a building. Measures the overall heat loss factor. The home is alternately heated with the furnace and an array of small heaters (co-heaters) to calculate heat-delivery efficiency.

Color Rendering Index
a measurement from 0 to 100 that indictes how accurately an artificial light source, as compared with an incandescent light, displays hues. The higher the index number, the more accurately the light is rendering colors. Incandescent lighting has a color rendering index above 95; standard high-pressure sodium lighting (such as orange-hued roadway lights) measures approximately 25; many fluorescent sources using rare earth phosphors have a color rendering index of 80 and above. (Adapted from U.S. ENERGY STAR)

Combination Oven Discharge
water released from an oven that includes a steam cycle or option

Combined Heat and Power
an integrated system that captures the heat, otherwise unused, generated by a single fuel source in the production of electrical power. Also known as cogeneration. (Adapted from U.S. Environmental Protection Agency)

Combustion Exhaust Gases
The most common gases resulting from fossil fuel combustion include carbon dioxide, sulfur dioxide, and a number of sulfur dioxides. These gases can be dangerous if allowed to build up indoors.

Commingled Waste
building waste streams that are combined on the project site and hauled away for sorting into recyclable streams. Also known as single-stream recycling.

A quality assurance process of verifying and documenting that a building and all of its energy and resource consuming operable systems and assemblies are planned, designed, installed, tested, operated, and maintained to meet the owner’s project requirements and under testing they are operating as intended by the building owner complying to the design and sequence of operations defined by its design engineers, and the architect. Typical components and systems commissioned include heating, ventilating, air conditioning (HVAC), electrical, plumbing, safety, security

Commissioning Authority (CxA)
the individual designated to organize, lead, and review the completion of commissioning process activities. The CxA facilitates communication among the owner, designer, and contractor to ensure that complex systems are installed and function in accordance with the owner’s project requirements. Owners should always engage an ANSI-ASHRAE Accredited Commissioning Professional to ensure the highest levels of credibility and professionalism.

Compact Fluorescent Lamp (CFL)
Small fluorescent light bulbs that can be used in place of incandescent light bulbs typically due to their self-contained ballast. CFLs consume significantly less electrical energy than as well as last 8–10 times longer than incandescent bulbs. CFL bulbs are a transitional technology that is more energy efficient than incandescent light bulbs, not as energy efficient as LED light bulbs and have performance issues such as flickering and taking time to reach full brightness. They also contain mercury, a poison, which makes proper and safe disposal difficult. (Green from an energy standpoint but not from a toxic waste standpoint)

Compensating Shower Valves
compensating valves are designed to keep bathing water
temperature in the shower fairly constant when other appliances such as a washing machine or toilet are in use and when the hot or cold water supply pressures change or the bathing water outlet temperatures changes. These types of valves are available~
-Thermostatic Compensating Valves are designed to keep bathing water temperatures in the shower fairly constant when other appliances such as a washing machine or toilet are in use and when the hot or cold water supply pressures change or the bathing water outlet temperatures changes. The response of this type of mechanism is different to that of a pressure balance compensating valve.
-Pressure Balance Compensating Valves are designed to keep bathing water temperature fairly constant when other appliances such as a washing machine or toilet are in use and when the hot or cold water supply pressures change.
-Conventional, Non-Compensating Valves are completely dependent on the user to adjust the temperature at all times by changing the adjustment.

Composite Wood
A product consisting of wood or plant particles of fibers bonded together by a synthetic rein or binder. Examples include plywood, particle-board, OSB, MDF, and composite door cores.

An organic fertilizer made by a composting process wherein bacteria in the soil is mixed with degradable trash.

Conditioned Space
An interior space that utilizes any method or air conditioning or heating to control the temperature and/or humidity levels. CFA is generally used to determine a building’s habitable floor area. [See California Code of Regulations, Title 24, Section 2-5302]

the measurement of the level of dissolved solids in water, using the ability of an electric current to pass through water. Because it is affected by temperature, conductivity is measured at 25°C for standardization.

Construction Impact Zone
the project’s development footprint plus the areas around the improvement where construction crews, equipment, and/or materials are staged and moved during construction

Conventional (designed) Home
A conventional home is one that is built to meet Building Code standards. It meets minimum requirements for safety and comfort. By a large contrast a green, high-performance home, such as a Net Zero or Zero Energy Ready, LEED Certified or Passivehaus home, is one that meets much higher energy and resource performance standards.

Conventional Irrigation
a region’s most common system for providing water to plants by nonnatural means. A conventional irrigation system commonly uses pressure to deliver water and distributes it through sprinkler heads above the ground.

Conventional Turf
Grass that requires considerable watering, mowing, and/or fertilizers. What is considered conventional may very by region, but turf should be classified as ‘conventional’ if it is a monoculture and requires regular irrigation, chemicals, or significant mowing.

Cool Roof: Specialized roofing materials designed to reflect the heat of the sun away from
building this reducing the cooling load and associated air conditioning costs.

Cooling Tower Blowdown
The used turbid water discharged from a cooling tower typically because increased salinity or alkalinity has caused scaling. Cooling tower blowdown may be too saline for use in landscape irrigation.

Covenants, Conditions, and Restrictions (CC&R)
limitations that may be placed on a property and its use and are made a condition of holding title or lease. Home Owners Associations impose CC&Rs on properties that are parts of their respective developments that set rules and limitations on what an owner is permitted to do with their respective properties.

A procedure that advocates the recycling of waste materials into new products rather than permanently disposing of them.

Cradle-to-Gate Assessment
analysis of a product’s partial life cycle, from resource extraction (cradle) to the factory gate (before it is transported for distribution and sale). It omits the use and the disposal phases of the product.

A procedure advocating the disposal of waste materials by means of landfill, incineration, etc. rather than recycling.

a segment of the circulation network that terminates without intersecting another segment of the circulation network

Cultural Landscape
an officially designated geographic area that includes both cultural and natural resources associated with a historic event, activity, or person or that exhibits other significant cultural or aesthetic values

Current Facilities Requirements (CFR)
In an Existing Building the operational document developed following the implementation of the owner’s project requirements as applicable, developed to confirm the owner’s current operational needs and requirements

For the purposes of PEER, this refers to the consumer served by the grid operator. For city projects, this includes customers of all classes billed by the utility, municipality or third-party supplier. For campuses, this includes business and groups of individuals (i.e., building tenants, or university departments) that are served by the grid operator. In the case where the building owner is the grid operator, “customer” refers to the individuals or groups of individuals on the consumer side of the meter, regardless of billing practices.

Department of Energy (US DOE)
While to DOE has many areas of responsibility, relative to Green Homes, the DOE has a program called Zero Energy Ready Homes with set standards for homes, that with a modest solar array (added when the home is built or after) are capable of being Net Zero Homes, essentially producing as much clean energy as it may pull from the power grid.

the application of natural light within a building to aid in the reduction of energy used for lighting, the assistance with supporting circadian rhythm, the addition of a biophilia element. By using various methodologies within the design of a building we can use natural sunlight illumination to our benefit and advantage as this light decreases reliance on electricity by using windows and skylights as a connection to the exterior.

Dismantlement of a building so that components can be reused and recycled.

Demand Controlled Circulation Pump
circulation pumps use looped systems to ensure hot water is immediately available while keeping unused cold water in the system. The demand controlled circulation pumps uses a switch or motion sensor to automatically activate the circulation of water, thus it saves water and energy.

Designed Landscape
Traditional landscape features that have been incorporated into the home site. Designed landscape features may include soft-scapes (e.g. grass, shrubs) or hard-scapes (e.g. rocks, fountains), but do not include driveways or areas under roof. Designed landscape also does not include preserved natural areas.

Demand Limit Controller
The way the demand controller controls loads is called the load control strategy. It is the definition of each load’s importance in relation to all other loads being controlled by the system. Generally, there are three load control strategies: priority (fixed), rotating or combination.

Design for the Environment (DfE)
An environmentally sensitive design model which reducing environmental damage through careful planning and material selection.

Disturbed Lot Area
Area of the lot that is directly affected by construction activity, including any activity that would lead to soil compaction or damage to vegetation.

Diverted Waste
Waste from construction or demolition that is not sent to a landfill or incinerator. Strategies for diverting waste include reclamation, recycling, or for certain materials mulching.

Domestic Hardwood
Deciduous trees whose wood is the only in the U.S. and where the growth of new trees exceeds the removal rate.

Double Pane Windows
a window assembly that utilizes two panes of glass separated by a spacer bar having a sealant applied to hold the assembly together creating an “insulated glazing unit”. Double or triple pane glass windows often contain argon, krypton, or other gases between panes to reduce heat flow and improve insulation additionally the glass can contain coatings like “Low-E” to reduce radiant energy transfer or exterior colored reflective coatings.

Drip Irrigation System
An irrigation system that slowly applies water to the root system of plants to maximize transpiration while minimizing wasted water and topsoil runoff. Drip irrigation usually involves a network of pipes and valves that rest on the soil or underground at the root zone.

Drought Tolerant Plants
Species of plants, shrubs and vines which generally do not require additional watering in order to thrive in their native habitats. Landscapes with drought tolerant plants usually require little or no watering.

Drywall Clips
devices to provide support for drywall at corners while eliminating the need for excessive wood backing.

Dual Flush Toilets
Toilets with two buttons or a flush valve with two flush option positions, one for intended for liquid and another for solid waste. The liquid waste option uses less water per flush.

Duct Blaster
A test that measures the air tightness of heating and cooling ducts.

The ability of building or any of its components to perform its required function in its service environment over the period of time without unforeseen cost for maintenance or repair.

Dust Spot Efficiency
A measure of a filter’s collection efficiency for fine particles.

Earth Sheltered Design
A home designed to be built partially or completely below ground, either by digging into existing ground or by covering over parts of the house. This design utilizes the constant temperature of the soil to improve energy efficiency and reduces environmental impact.

Earth’s Thermal Energy
A little below the surface, the earth keeps a constant temperature close to the human comfort level, and this type of heating can be used efficiently for geothermal heating systems.

Earthen Flooring
Earth that has been compacted with straw or other fibers and conditioned with various oils to form a hard surface. Fairly labor intensive, but relatively easy to repair and usually very low bodied energy and inexpensive materials.

A reusable, earth-friendly mailing envelope that contains at least 30% post consumer waste and is printed with soy or water based inks.

EER- (Energy Efficiency Ration see SEER)

Electric Thermostat Timer
Referred to as programmable thermostats. Programmable thermostats save energy by permitting occupants to set temperatures according to whether the house is occupied. These thermostats can automatically store and repeat settings daily with allowance for manual override. By eliminating manual setback, they allow the setting of more comfortable temperatures in the morning before occupants wake. Temperature setback can be adjusted for both heating and cooling seasons. Programmable thermostats can be set to adjust the temperature setting according to a user’s schedule. These thermostats typically have a digital interface that allows more precise temperature control and a wider range of options or features.

Electric Vehicle Supply Equipment
the conductors, including the ungrounded, grounded, and equipment grounding conductors, the electric vehicle connectors, attachment plugs, and all other fittings, devices, power outlets or apparatuses installed specifically for the purpose of delivering energy from the premises wiring to the electric vehicle. (National Electric Codes and California Article 625)

Electronic Waste
discarded office equipment (computers, monitors, copiers, printers, scanners, fax machines), appliances (refrigerators, dishwashers, water coolers), external power adapters, and televisions and other audiovisual equipment

Elemental Mercury
mercury in its purest form (rather than a mercury-containing compound), the vapor of which is commonly used in fluorescent and other bulb types as it illuminates phosphors when electrically charged

Embodied Energy
The Combined energy required to extract, manufacture, assemble, finish, transport and install building materials including the molecular energy already existing in a product’s content. 

Emergency Lighting
a luminaire (light fixture) that operates only during emergency conditions and is always off during normal building operation

The release of any solid, liquid, gas or vapor into the environment from a particular source, including smokestacks, chimneys, combustion devices, motor vehicles, fluids and granular solid waste.

Emissions Trading
A system created by the Kyoto Protocol, which allows countries that are under-target on emissions to swap spare emissions with over-target countries with the goal of limiting carbon emissions worldwide.

Employment Center
a nonresidential area of at least 5 acres (2 hectares) with a job density of at least 50 employees per net acre (at least 125 employees per hectare net)

the exterior plus semi-exterior portions of the building. Exterior consists of the elements of a building that separate interior conditioned spaces from the outside (i.e., the wall assembly). Semiexterior consists of the elements of a building that separate conditioned space from unconditioned space or that encloses semi-heated space through which thermal energy may be transferred to or from the exterior or conditioned or unconditioned spaces (e.g., attic, crawl space, basement).

Energy Assessment
A written report prepared by a qualified party evaluating energy usage, highlighting weak points in energy efficiency, and identifying cost-savings measures. Sometimes termed an ASHRAE Level I Assessment.

Energy Audit
There are three levels of ASHRAE Energy Audits the Level 1 is a special inspection performed to determine where there are energy inefficiencies in a home or building that are low to no cost strategies to remedy. In and ASHRAE Level II Audit a qualified tester uses methods and measurements that comply with industry standards and involves collection of detailed data and an engineering analysis. A written report should include recommendations and a detailed cost and savings analysis. In an ASHRAE Level III Audit the level of analysis includes very detailed analysis of potential Capital Investment Energy Efficiency Measures implementation and where their savings will balance their expense of installation and implementation to determine their Return on Investment. This is at times referred to as an Investment Grade Audit.

Energy Efficiency
Products or systems designed to use less energy for the same or higher performance. It can also save money on utilities by being less reliable on fossil fuels and depending more on renewable resources.

Energy Efficient Appliances
Products that use less energy than conventional models. The ENERGY STAR® label is a credible third-party certification of a product’s energy efficiency. Consumers can also refer to the FTC’s Energy Guide label, a yellow label affixed to most appliances today. Clothes washers, dishwashers, refrigerators, freezers, water heaters, window air conditioners, central air conditioners, furnaces, boilers, heat pumps, and pool heaters can get the label. Televisions, ranges, ovens, clothes dryers, humidifiers, and dehumidifiers do not receive such labels.

Energy Efficient Light Fixtures
The fixture or the type of bulbs used in a fixture. Compact fluorescent lights (CFLs) and light emitting diodes (LEDs) are becoming more common in homes and buildings and they are more efficient and last longer than incandescent bulbs.

Energy Efficient Mortgage (EEM)
Loan products that take a home’s energy efficiency into account when determining the qualifying ratios for a buyer. The rationale is that an efficient home will result in lower monthly bills and potentially make buyers of such homes less risky borrowers than others. EEMs primarily apply to new construction. In some markets, an energy improvement mortgage (EIM) can be used to make energy improvements.

Energy Guide Label
An appliance label that provides an estimate of how much energy the appliance uses, compares energy use of similar products, and lists approximate annual operating costs. Required by the U.S. Department of Energy.

Energy Heel Truss
An engineered roofing trust with an elevated portion at the wall plate line to provide for full depth insulation.

Energy Improvement Mortgage (EIM)
A mortgage intended for existing homes for the purpose of installing energy efficiency improvements.

Energy Modeling
A computer model used to analyze a building’s energy systems in order to project its possible consumption rate.

Energy Rated
See “Energy Audit” above. An energy rating provides a score for home during energy audits. Energy ratings usually have to be used to determine the ratios for an energy efficient mortgage.

Energy Recovery
A process of attaining energy from a waste product. An example includes ERV devices.

Energy Recovery Ventilator (ERV)
An Energy Recovery device which is part of the buildings air circulation system which provides a pathway to expel stale air and take in fresh air in an adjacent pathway to transfer embodied energy without losing much of the energy used to heat or cool the interior of the facility. An ERV runs the air coming in and the air being expelled through a heat exchanger allowing the warm air being expelled in the winter to heat the incoming air from outside. In the summer, the cool air being expelled chills the warmer air coming into the building through the ERV. ERVs also help maintain proper interior humidity levels. (Also See Heat Recovery Ventilator).

Energy Service Provider
a designation that allows an outside entity, such as USGBC, to access water and energy usage information that a building management team maintains with ENERGY STAR Portfolio Manager or a similar tool

Energy Star®
Introduced in 1992 by the U.S. Environmental Protection Agency (EPA) as a voluntary labeling program designed to identify and promote energy efficient products to help reduce greenhouse emissions by identifying energy efficient products. Energy Star is now an energy efficiency rating program administered by the EPA. Originally designed for computers and monitors, it has now expanded to include office products, major appliances, lighting, home electronics and more. New expanded programs now also include complete buildings such as homes, commercial and industrial buildings.

Energy Star® Air-Conditioning

See “Energy Star” above.
Energy Star® Appliance(s)
See “Energy Star” above.


Energy Star Home

Homes built to a high standard of energy efficiency (at least 15% more efficient than the International Energy Conservation Code). For more information, visit


Energy Star with Indoor Air Package (IAP)

A certification that recognizes homes with
systems to ensure high standards of indoor air quality and rated as an Energy Star Qualified

Energy Star® Hot Water Heater
See “Energy Star” above.

Energy Star® Light Fixtures
See “Energy Star” above.


Engineered Lumber

Engineered lumber are construction materials designed to reduce the amount of material needed for framing a building. By designing away from full dimension sawn lumber, less large growth trees need to be cut and smaller dimension lumber can be assembled in various configurations to span long distances with equal or often superior strength. Trusses have always been a good example of engineered lumber by using smaller dimension lumber and distributing forces more efficiently, the materials needed are a fraction of that required to span the same distances with sawn lumber.


engineered nanomaterial

a substance designed at the molecular (nanometer) level. Because of its small size, it has novel properties generally not seen in its conventional bulk counterpart. See the Australian National Industrial Chemicals Notification and Assessment Scheme,


Engineered Studs

A little different than engineered lumber, usually smaller diameter stock is shredded and reassembled by forming them into nominal sized framing materials. The material is combined with a binder and compressed into large billets that are then cut to dimensional size. Similar products have been around for many years in the form of oriented strand board dimensionally stable and less susceptible to warping. These studs are considerably heavier than sawn wood, cost about twice as much and may be subject to water damage.


Engineered Wood Products
A type of composite wood with superior durability and strength. Thinner or fewer pieces of engineered wood are required to meet the same strength requirements than would be needed with traditional wood.


Enhanced Air Filtration
Superior media filters, such as high level HEPA or even MERV filters on HVAC equipment.


Enterprise Green Communities
A non-profit organization which provides resources and expertise to enable developers to build and rehabilitate homes that are healthier, more energy efficient and better for the environment, yet still affordable. Green Communities is the first national green building program developed for affordable housing.


environmental product declaration

a statement that the item meets the environmental requirements of ISO 14021–1999, ISO 14025–2006 and EN 15804, or ISO 21930–2007


Envelope (building)

The envelope of a building refers to those elements that divide the indoors from the outdoors: the foundation, exterior walls, exterior windows and doors, attic floor and/or roof. It is important to construct an envelope well and tightly to ensure the indoor comfort of a home.


Environmental Aspect: The way a manufacturer’s activities or products can relate positively or negatively with the environment.


Environmental Audit: An assessment of a company’s (or person’s) compliance with environmental requirements.


Environmental Impact: Any positive or negative change to the environment resulting from manufacturing processes.


Environmental Protection Agency (EPA)

The Environmental Protection Agency, or EPA, is an office designated by the government dedicated to protecting “human health and the environment.” The EPA administers such initiatives as the Energy Star program.



A combination of processes in which materials of the earth’s surface are loosened,
dissolved or worn away, and transported from one place to another by natural agents such as
water, wind or gravity.


ET Irrigation Control
A system that uses sensors to measure soil moisture and determine whether watering is necessary.


Evaporative Cooler
Also know as swamp cooler. A simple cooling system that operates by moving air across or through a wet pad.



the combination of evaporation and plant transpiration into the atmosphere. Evaporation occurs when liquid water from soil, plant surfaces, or water bodies becomes vapor. Transpiration is the movement of water through a plant and the subsequent loss of water vapor.


extended producer responsibility

measures undertaken by the maker of a product to accept its own and sometimes other manufacturers’ products as postconsumer waste at the end of the products’ useful life. Producers recover and recycle the materials for use in new products of the same type. To count toward credit compliance, a program must be widely available. For carpet, extended producer responsibility must be consistent with NSF/ANSI 140–2007. Also known as closed-loop program or product take-back.


extensive vegetated roof

a roof that is covered with plants and typically not designed for general access. Usually an extensive system is a rugged green roof that requires little maintenance once established. The planting medium in extensive vegetated roofs ranges from 1 to 6 inches in depth. (Adapted from U.S. EPA) exterior vegetated surface area the total area of vegetation on the project site, including vegetated roofs and turf grass


exterior vegetated surface area

the total area of vegetation on the project site, including vegetated roofs and turf grass

external meter

a device installed on the outside of a water pipe to record the volume of water passing through it. Also known as a clamp-on meter

The elements of the building exterior that include Windows, Doors and Skylights. The authority on Fenestration is the National Fenestration Rating Council; The NFRC serves the public by driving widespread usage of fair, accurate, and credible energy performance ratings, serves members by giving them a voice in the ratings development process, and serves the industry by creating an environment of competition that drives energy performance.

Fiber Cement
A siding that is more durable than wood and is termite resistant, water resistant, non-combustible, and warranted to last 50 years. It is composed of cement, sand, and cellulose fiber that has been autoclaved (cured with pressurized steam) to increase its strength and dimensional stability. The fiber is added as reinforcement to prevent cracking.

Finger Jointed Studs
Often the lumber being cut today is a shadow of the old growth lumber of yesterday in quality, density and overall suitability for construction. However, by conserving the shorter sections of lumber and removing the undesirable wane and knots, these sections can be fitted with special splicing techniques to form longer and more dimensionally stable lumber. The application is usually limited to vertical installation because of this splicing technique.

Floor Area Ratio (FAR)
the density of nonresidential land use, exclusive of parking, measured as the total nonresidential building floor area divided by the total buildable land area available for nonresidential structures. For example, on a site with 10,000 square feet (930 square meters) of buildable land area, an FAR of 1.0 would be 10,000 square feet (930 square meters) of building floor area. On the same site, an FAR of 1.5 would be 15,000 square feet (1395 square meters), an FAR of 2.0 would be 20,000 square feet (1860 square meters), and an FAR of 0.5 would be 5,000 square feet (465 square meters).

Flow Reducer (water)
A device attached either just downstream from the water shutoff valve to a building or at the outlet of a fixture designed to reduce or limit the amount of water flow in relation to the delivery pressure from the street. Flow reducers can cut the flow of water dramatically saving thousands of gallons each year in a dwelling or even more in larger buildings. Flow reducers are never installed on automatic fire extinguishing systems for obvious reasons.

Fluorinated Gas
A greenhouse gas typically associated with refrigerants and aerosols.

A non-flammable liquid or gas used as propellants; often used in spray cans, they are classified as ozone-depleting substances.

Fly Ash
A byproduct of a coal burning furnace, usually from power generation equipment.
Consisting mostly of silica, alumina and iron, and fine glass like particles. When mixed with lime and water it forms a cementious material similar to Portland cement (a bonding material in concrete). The cement produced is hard, smooth and easily worked. Other uses include fills for abandoned coal mines, sealing liners for hazardous waste sites and seaside docking areas.

A naturally occurring Volatile Organic Compound found in small amounts in
animals and plants, but is an irritant to most people when present in high concentrations—causing headaches, dizziness, mental impairment, and other symptoms. Formaldehyde may be a

Forest Stewardship Council (FSC)
A non-profit organization that encourages the responsible management of the world’s forests. FSC sets high standards that ensure forestry is practiced in an environmentally responsible, socially beneficial, and economically viable way. Landowners and companies that sell timber or forest products seek certification as a way to verify to consumers that they have practiced forestry consistent with FSC standards. Independent, certification organizations are accredited by FSC to assess forest management and determine if standards have been met. Certifiers also verify that companies claiming to sell FSC certified products have tracked their supply back to FSC-certified sources.

Colorless, pungent, toxic (the cause of many cancers or respiratory ailments) material used to as a component in glues for wood products.

Fossil Fuel
The term “fossil fuel” refers generally to oil, coal, and gas. They  get this name because they are the remains of living organisms, which have been converted to fuel over millions of years by the natural forces of heat and pressure. When you use a fossil fuel, one of the waste products is carbon dioxide which contributes to your carbon footprint.

Fossil fuels are the opposite of clean energy; using them causes pollution. Fossil fuels are generally used in conventional homes, but not (or to a much smaller degree) in high-performance homes.

Fossil fuels are also volatile in price and can cause both high energy bills and high fluctuations from month-to-month and year-to-year, depending on supply. The best ways to minimize the impact of these costs are to use various strategies to conserve energy and to use alternative energy sources instead.

Foundation Drain
the water discharged from a subsurface drainage system. If a building foundation is below the water table, a sump pump may be required. Discharge from the sump may be stored and used for irrigation.

Typically refers to the structural support of a building. It can be compared to skeletons in living beings. In homes, framing is generally made of lumber. Framing makes up part of a home’s envelope as well as its interior partitions. In commercial and other more intensive construction it can be concrete, steel, aluminum, composites, masonry, and light gauge metal.

Freight Village
a cluster of freight-related businesses that include intermodal transfer operations. Freight villages may offer logistics services, integrated distribution, warehousing capabilities, showrooms, and support services. Such support services may include security, maintenance, mail, banking, customs and import management assistance, cafeterias, restaurants, office space, conference rooms, hotels, and public or activity center transportation.

Fuel Cell
A clean fuel source that converts chemical energy from hydrogen to electrical energy. Yields zero emissions.

Full Spectrum Lights: Lights that imitate the natural light spectrum and are therefore considered healthier.

Functional Entry
a building opening designed to be used by pedestrians and open during regular business hours. It does not include any door exclusively designated as an emergency exit, or a garage door not designed as a pedestrian entrance.

Furniture and Furnishings
the stand-alone furniture items purchased for the project, including individual and group seating; open-plan and private-office workstations; desks and tables; storage units, credenzas, bookshelves, filing cabinets, and other case goods; wall-mounted visual-display products (e.g., marker boards and tack boards, excluding electronic displays); and miscellaneous items, such as easels, mobile carts, freestanding screens, installed fabrics, and movable partitions. Hospitality furniture is included as applicable to the project. Office accessories, such as desktop blotters, trays, tape dispensers, waste baskets, and all electrical items, such as lighting and small appliances, are excluded.

Generator (electrical) 
A power plant producing electricity for a large number of people.

Geothermal Heat
A technology that utilizes the warmth from subsurface water to heat buildings, and it also extracts this heat to put back into the ground for cooling. Find more information on geothermal heating.

Geothermal is literally “earth heat”, or heat derived from the earth.  It is a passive, renewable, clean energy source.

Geo Thermal Heat System (Closed Loop)
Geothermal heat pumps (GHPs) use the constant temperature of the earth to provide cooling and heating for a home. A loop of piping is buried in the ground and fluid circulates through the loop. In the summer, the fluid uses the cooler temperature of the ground to provide indoor cooling. During colder months, the geothermal heat pump uses the below-ground temperature, which is significantly warmer than the outside air, to warm a home.

Geothermal HVAC
See “Geo Thermal Heat System (Closed Loop)” above

Global Warming
A significant variation from one climatic condition to another due to human activities.

Granny Flat
Another name for an accessory dwelling unit. Granny flats are usually associated
as being attached to the main dwelling unit, but may also be detached. City regulations limit the number and size of these units.

waste water from lavatories, laundry, showers, baths and sinks only. This water can be stored in special equipment and may then be used to water lawns, gardens or other relatively benign non-potable uses such as groundwater recharge. Graywater systems must comply with the requirements of California Plumbing Code Appendix Chapter G to qualify as a green element. Water from toilets is called black water and is not eligible for any type of reuse under this program and must be properly drained to the sewer or septic system.
. Project teams should comply with the graywater definition established by the authority having jurisdiction in the project area.

Gray Water System
A Gray Water System captures a household’s gray water, often via a drum or barrel, which is then piped or drained into a home’s landscaping. It is important to check local building codes to make sure that a gray water system is permitted.

“Green” is a widely-used term that can mean a wide variety of things to different people. Generally, it refers to systems, processes, and materials that are environmentally and ecologically sensitive; that work with the Earth, protect it or improve it.  “Sustainable” is often used as a synonym for “green”.

Green Building
Green building is both a noun and a verb.
As a noun, it refers to buildings that have been built to use energy, water, and materials resources responsibly. It also reduces environmental impact and minimizes waste in order to create a healthy environment and keep operation and maintenance costs low. The entire lifecycle of the building and its components is considered.
As a verb, it refers to labor and materials that are responsibly-sourced and resource-efficient.

Green building strategies can be used in a new building or building renovation and are applicable to all phases of the life of a building: development and siting, design and construction, operation and maintenance, and remodeling/renovation to eventual demolition.

When a building is described as “green”, it is helpful to understand what the developer, designer, and/or builder mean, as this term can vary widely from region to region and even profession to profession.

Green Building Standard
Green building standards are objective, generally quantitative, rating systems by which the “greenness” of a building can be commonly understood.

Examples of green building standards include HERS, LEED, Passive House, and the Living Building Challenge. The different standards emphasize different areas such as materials sourcing and operating efficiency.

These ratings can positively affect a building’s assessment when obtaining third-party financing for building and remodeling; they also set the foundation for a more accurate, consistent understanding between realtors, buyers, and sellers about the high-performance elements of a sustainable building.

Green Guides
Guidelines published by the Federal Trade Commission (FTC) providing standards for advertising claims that a product is green.

Green Electricity Provider
A utility that generates or invests in electricity from renewable sources and sells it for a small premium over standard electricity costs.

Green Infrastructure
a soil- and vegetation-based approach to wet weather management that is cost-effective, sustainable, and environmentally friendly. Green infrastructure management approaches and technologies infiltrate, evapotranspire, capture and reuse stormwater to maintain or restore natural hydrologies. (Adapted from U.S. Environmental Protection Agency)

Green Living Philosophy
A way of living that involves a holistic approach to preservation and conservation of natural resources. It aims to provide a better understanding of the balance between human action and natural environmental resources and improve health and well-being. It also entails creating a better understanding of social responsibility and what effect choices made by people and business have on the environment.

Green /Living Roof
A green or vegetated roof provides the function of a conventional roof while
allowing plants to grow on the surface. A vegetated roof includes water proofing, a drainage
system, filter layer, a lightweight growing medium, and plants. Two basic types exist:
INTENSIVE and EXTENSIVE. Intensive systems are usually over five inches of soil medium
and can require special engineering to handle weight. Extensive living roofs are typically less than 5 inches of planting medium, usually on a rack or cup system. Both systems can require irrigation which is often supplied through storm water retention somewhere else on site. By using native plant species maintenance and watering needs can be reduced. Key benefits include: Reduction in Heat Island Effect, Storm Water attenuation, improvement in Indoor Environmental Quality, and reconstitution of wildlife habitat.

Green Power (also see Renewable Energy)
a subset of electrical energy composed of grid-based electricity produced from renewable energy sources. Generally this is the production of electricity from environmentally friendly
sources such as photovoltaic geothermal, hydroelectric, biomass, hydrogen fuel cells, ocean
energy and wind power. As with all forms of electricity generation, there are significant costs involved and in some cases undesirable byproducts such as vane noise and unsightly appearance or diversion of wild waterways. While large scale versions of these methods are not practical within an urban environment, many homes and businesses are taking advantage of solar systems that not only make electricity but also heat water and interior environments.

Green Roof: A green or vegetated roof provides the function of a conventional roof while allowing plants to grow on the surface. A vegetated roof includes water proofing, a drainage system, filter layer, a lightweight growing medium, and plants. Two basic types exist: INTENSIVE and EXTENSIVE. Intensive systems are usually over five inches of soil medium and can require special engineering to handle weight. Extensive living roofs are typically less than 5 inches of planting medium, usually on a rack or cup system. Both systems can require irrigation which is often supplied through storm water retention somewhere else on site. By using native plant species maintenance and watering needs can be reduced. Key benefits include: Reduction in Heat Island Effect, Storm Water attenuation, improvement in Indoor Environmental Quality, and reconstitution of wildlife habitat.

Green Seal
A certification for construction products, such as window sealant, paints, and adhesives, attesting that the products are low in toxicity levels and were manufactured such that they can be used with minimal impact on the environment.

Green Vehicles
vehicles achieving a minimum green score of 45 on the American Council for an Energy Efficient Economy (ACEEE) annual vehicle rating guide (or a local equivalent for projects outside the U.S.).

area that has not been graded, compacted, cleared, or disturbed and that supports (or could support) open space, habitat, or natural hydrology.
See also: previously disturbed

Greenhouse Effect
The warming of the Earth’s atmosphere due to a buildup of gases in the air.

Greenhouse Gas: Any emitted gas contributing to the greenhouse effect (carbon dioxide, methane, and nitrous oxide) by staying trapped in the in the atmosphere and intensifying the sun’s heat as it radiates to the earth and impacts ozone depletion, smog and climate change.

Falsely promoting or exaggerating the greenness of a product or service.

Gross Floor Area (GFA)
Generally, the gross floor area is the sum of the floor areas of the spaces within the building, including basements, mezzanine and intermediate-floored tiers, and penthouses with headroom height of 7.5 ft (2.2 meters) or greater. Measurements must be taken from the exterior faces of exterior walls OR from the centerline of walls separating buildings, OR (for LEED ID+C projects) from the centerline of walls separating spaces. Excludes non-enclosed (or non-enclosable) roofed-over areas, such as exterior covered walkways, porches, terraces or steps, roof overhangs, and similar features. Excludes air shafts, pipe trenches, chimneys and floor area dedicated to the parking and circulation of motor vehicles

A site, such as a mall or commercial facility, which has been abandoned, leaving behind a large developed but empty area.

Hardscape (landscaping element) Defined by the American Society of Landscape Architects as “elements added to a natural landscape, such as paving stones, gravel, walkways, irrigation systems, roads, retaining walls, sculpture, street amenities, fountains, and other mechanical features.” Hardscapes are often impermeable, but they are not impermeable by definition. Halocarbons manmade chemicals that, when released into the atmosphere as greenhouse gases, can disrupt global climate patterns. Their most common use is in refrigeration and air conditioning technologies. Harvested Rainwater Rain channeled by gutters to a storage unit and can then be reused for different things. Hazardous Material any item or agent (biological, chemical, physical) that has the potential to cause harm to humans, animals, or the environment, either by itself or through interaction with other factors Heat Exchanger The element that exchanges heat or cool between one thermal flow with another. This can be the A-Coil in a typical HVAC install, the fan-coli on a terminal unit and even the thermal exchange coil with the ground through a buried loop. Heat Island Effect Is the term for thermal absorption by hardscape, such as dark, nonreflective pavement and buildings, and its subsequent heat re-radiation to surrounding areas. Other contributing factors may include vehicle exhaust, air-conditioners, and street equipment. Tall buildings and narrow streets reduce airflow and exacerbate the effect. As cities replace natural landscaping with streets, buildings and other infrastructure, the average ambient temperatures within these areas begin to rise, as much as 10 degrees F higher than less developed rural areas. This increases the need for cooling energy, can exacerbate pollution problems and may be contributing to the problem of global warming. Heat islands can be effectively reduced by shading streets with trees and improving the urban forest over all. Ironically, heat islands can be beneficial in cold climates in the winter by reducing heating demands; however the overall effect is much more on the negative side. Heat Recovery Systems  Mechanical devices used to capture waste heat from another system to replace the heat that would otherwise come from a primary energy source. Heat Recovery Ventilator (HRV) A Heat Recovery Ventilation system is a device that allows a home to expel stale air and take in fresh air without losing much if any energy used to heat or cool the interior of the home. A HRV runs the air coming in and the air being expelled through a heat exchanger allowing the warm air being expelled in the winter to heat the incoming air from outside. In the summer, the cool air being expelled chills the warmer air coming into the house through the HRV. (Also See Energy Recovery Ventilator). High Albedo Materials Materials with a high amount of surface reflectivity. High Efficiency Furnace Furnaces that have an Annual Fuel Utilization Efficiency (AFUE) of 85% (oil) and 90% (gas) or higher. In general the higher the AFUE, the more efficient the furnace. The Energy Guide label on the equipment can be consulted to determine whether a furnace is efficient. The label was recently updated by the Federal Trade Commission, and more information on the Energy Guide label is available at High Efficiency Toilets Toilets that use no more than 1.3 gallons per flush. This value will continue to evolve based on the EPA current determinations. High Efficiency Water Heater Hot water heaters are typically defined as being highly efficient once they have reached an Energy factor or 0.85. Efficiency factors of 90% and higher are available and may be incentivized in one form or another through federal, state or utility programs. High-Performance Building Similar in some goals to o a green building, these buildings  specifically aim to be energy efficient, and have a low relative Energy Use Index as compared to buildings of similar type. High Performance Home A high-performance home is typically defined as one which is significantly more energy efficient than conventional homes. High performance is measured using standard ratings systems like LEED for Homes, Passivehaus and HERS. They achieve enhanced performance through thoughtfully combining an air-tight, well insulated, thermal envelope; a highly efficient heating and cooling system; ventilation and air filtration for high indoor air quality; and even select the option of clean energy sources, such as solar photovoltaic electricity. High-Quality Duct System An alternative system in which all the ducts are sealed with fibrated latex material and fiberglass tape, and then run outside to avoid significant heating and cooling losses and potential health threats caused by de/pressurizing a house. Highway a transportation thoroughfare intended for motor vehicles with limited access points, prohibitions on human-powered vehicles, and higher speeds than local roads. A highway generally connects cities and towns. Historic Building a building or structure with historic, architectural, engineering, archeological, or cultural significance that is listed or determined to be eligible as a historic structure or building, or as a contributing building or structure in a designated historic district. The historic designation must be made by a local historic preservation review board or similar body, and the structure must be listed in a state register of historic places, be listed in the National Register of Historic Places (or a local equivalent outside the U.S.), or have been determined eligible for listing. Historic District a group of buildings, structures, objects, and sites that have been designated or determined to be eligible as historically and architecturally significant, and categorized as either contributing or noncontributing to the historic nature of the district Home Energy Rating System (HERS) A scoring system established by the Residential Energy Services Network (RESNET). Homes built to the specifications of the HERS Reference Home (based on the 2006 International Energy Conservation Code) scores a HERS Index of 100, while a net zero energy home scores a HERS Index of 0. Each 1-point decrease in the HERS Index corresponds to a 1% reduction in energy consumption compared to the HERS Reference Home. Thus, a home with a HERS Index of 85 is 15% more energy efficient than the HERS Reference Home, and a home with a HERS Index of 80 is 20% more energy efficient. Homogeneous Material an item that consists of only one material throughout or a combination of multiple materials that cannot be mechanically disjointed, excluding surface coatings Hubbert’s Curve A prediction, made by a geologist in the late 1950s, that classified fossil fuels as finite and said that after a peak time access to these resources would rapidly decline, eventually diminishing entirely. HVAC The acronym for Heating, Ventilation and Air Conditioning HVAC (16 SEER+) A rating system, Seasonal Energy Efficiency Ratio (SEER), used to measure the efficiency of central air conditioners and air source heat pumps. The higher the rating, the more energy efficient it is. For reference, air conditioners that are 14 or higher SEER meet ENERGY STAR criteria. Hydro Chlorofluorocarbons (HCFCs) Chemical Compounds that are as well used as Refrigerants in building equipment that deplete the stratospheric ozone layer, but to a lesser extent than CFCs. Hydrofluorcarbon A greenhouse gas. Hydronic System A heating or cooling system that relies on the circulation of water as the heat transfer medium. A typical example is a boiler with hot water circulated through radiators. Hydronic Radiant Heating This is a system of heating a building by using a central boiler or hot water heater to distribute heat under a floor through a system of tubes just under the flooring surface. A single heater may be zoned to provide independent heat to different parts of a building as needed. The heating system is efficient and provides a comfortable conditioned room. Hydropower (hydroelectricity) Clean energy technology that uses moving water to produce electricity. Water flows through a hydraulic turbine, which spins and then rotates generators and converts rotational energy into electricity. Hydrozone a group of plantings with similar water needs

the incident luminous flux density on a differential element of surface located at a point and oriented in a particular direction, expressed in lumens per unit area. Since the area involved is differential, it is customary to refer to this as illuminance at a point. The unit name depends on the unit of measurement for area: foot-candles if square feet are used for area, and lux if square meters are used. (Adapted from IES) In lay terms, illuminance is a measurement of light striking a surface. It is expressed in foot-candles in the U.S. (based on square feet) and in lux in most other countries (based on square meters).

Impervious Surface
an area of ground that development and building have modified in such a way that precipitation cannot infiltrate downward through the soil. Examples of impervious surfaces include roofs, paved roads and parking areas, sidewalks, and soils that have been compacted either by design or by use.

Indigenous Materials
Building with materials that are produced in an area near to where the construction is taking place. This reduces building costs and helps to boost local economies.

Individual Occupant Space
an area where an occupant performs distinct tasks. Individual occupant spaces may be within multioccupant spaces and should be treated separately where possible.

Indoor Air Quality (IAQ)
The classification and even measurement of the overall cleanliness of the air within a building or home. any measurable elements contribute to IAQ including ventilation, temperature and humidity, airborne contaminants, air filtration quality and outdoor air exchange are just some of the contributors to IAQ. Common indoor air-quality problems include mold spores; outgassing of noxious chemicals including volatile organic compounds by paints, finishes, adhesives, furniture and building materials; radon gas; and humidity levels that are too high or too low.  IAQ is the acronym for Indoor Air Quality. As buildings become tighter, indoor air quality suffers unless specific measures are taken to improve the exchange of fresh air without sacrificing heating/cooling economy.

Industrial Process Water
any water discharged from a factory setting. Before this water can be used for irrigation, its quality needs to be checked. Saline or corrosive water should not be used for irrigation.

Infill Site
a site where at least 75% of the land area, exclusive of rights-of-way, within ½ mile (800 meters) of the project boundary is previously developed. A street or other right-of-way does not constitute previously developed land; it is the status of property on the other side of right-of-way or the street that matters.

LEED ND only:
a site that meets any of the following four conditions:
a. At least 75% of its boundary borders parcels that individually are at least 50% previously developed, and that in aggregate are at least 75% previously developed
b. The site, in combination with bordering parcels, forms an aggregate parcel whose boundary is 75% bounded by parcels that individually are at least 50% previously developed, and that in aggregate are at least 75% previously developed
c. At least 75% of the land area, exclusive of rights-of-way, within ½ mile (800 meters) of the project boundary is previously developed
d. The lands within ½ mile (800 meters) of the project boundary have a preproject connectivity of at least 140 intersections per square mile (54 intersections per square kilometer)
The circulation network itself does not constitute previously developed land; it is the status of property on the other side of the segment of circulation network that matters. For conditions (a) and (b) above, any fraction of the perimeter that borders a water body is excluded from the calculation. “

This is the entrance of exterior unconditioned air to a building through various means into a building. Under the older codes, a dwelling generally had the equivalent of a four-foot diameter hole in infiltration leakage. While newer buildings greatly improve this leakage, other problems such as poor indoor air quality and transpiration of moisture to internal stud bays can occurs and must be remedied with such items as air-to-air exchangers and specialized waterproofing techniques.

Informal Transit
a transit service in which individuals travel together in a passenger car or small van that seats at least four people. It can include human-powered conveyances, which must accommodate at least two people. It must include an enclosed passenger seating area, fixed route service, fixed fare structure, regular operation, and the ability to pick up multiple riders.

IT annual energy
electricity consumption by information technology and telecom equipment which includes servers, networking, and storage equipment over the course of a year

Infrared (thermal) Emittance
a value between 0 and 1 (or 0% and 100%) that indicates the ability of a material to shed infrared radiation (heat). A cool roof should have a high thermal emittance. The wavelength range for radiant energy is roughly 5 to 40 micrometers. Most building materials (including glass) are opaque in this part of the spectrum and have an emittance of roughly 0.9, or 90%. Clean, bare metals, such as untarnished galvanized steel, have a low emittance and are the most important exceptions to the 0.9 rule. In contrast, aluminum roof coatings have intermediate emittance levels. (Adapted from Lawrence Berkeley National Laboratory)

Insulated Concrete Forms (ICF)
Expanded polystyrene foam (EPS), high density polyethylene (HDPE), polyvinylchloride (PVC) or polycarbonate (PC) is cast or injection molded in various panel shapes and form the permanent forming method for reinforced concrete walls. These highly insulated forms have various thermal resistance values (R values) ranging from about R-22 up to about R-40. In hot or cold climates, these forms can significantly reduce heating and cooling loads. The panels are usually pre-engineered and produce a fire resistive barrier up to 4-hour rated.

Insulated Glass Windows
An assembly consisting of two panes of glass separated by a space (spacer bar). The perimeter of the glass is sealed, allowing no movement of outside air into the space. The space, itself, can be filled with dehydrated air, or with an inert lesser-conductive gas. The type of glass, glass coatings, spacer and gas used in the space contribute to the overall insulating efficiency of the glass.

Insulation is any material used in a building to minimize the energy required to maintain comfortable indoor temperatures relative to outside temperatures. Insulation is the best way to reduce heating and cooling costs while maximizing indoor comfort. There are many different types of insulation; some of the most common are fiberglass and mineral wool batts, foam boards, spray foam, and cellulose.

In addition to minimizing energy use, insulation can also be used as a moisture barrier and soundproofing.

Insulation’s effectiveness is measured in “R values”, a number that describes how resistant the material is to heat flowing through it. Higher R values are always better. However, the cost to install varies greatly, depending upon whether the location is a foundation slab or wall; a framed floor, wall, or roof; or window.  Therefore, different types and amounts of insulation are typically installed in these different areas.

Insulation is generally used exclusively as part of a home’s thermal envelope, except for soundproofing which can be placed in interior walls and partitions.

Insulation – Blown
Fiberglass, cellulose, or wool insulation that is blown in. It is often easier and less expensive to install than batts of fiberglass insulation.

Insulation-Compatible Air-Tight Recessed Lighting (IC-AT)
Lighting that eliminates the heat-producing chimney effect of convention incandescent lighting.

Insulation – Foam in Place
A product that acts as an air barrier and provides insulation and air sealing in one step. Most foam insulation products have a higher R-value per inch than fiberglass batt insulation. Using foam insulation increases energy efficiency because smaller heating and cooling equipment is required.

Integral Labeling
an information conveyance system that cannot be easily removed. For furniture, such labeling may include radio frequency identification, engraving, embossing, or other permanent marking containing information on material origin, properties, and date of manufacture.

Integrated Pest Management
a method of pest management that protects human health and the surrounding environment, and improves economic returns through the most effective, least-risk option

Integrated Project Delivery
an approach that involves people, systems, and business structures (contractual and legal agreements) and practices. The process harnesses the talents and insights of all participants to improve results, increase value to the owner, reduce waste, and maximize efficiency through all phases of design, fabrication, and construction.

Intensive Vegetated Roof
a roof that, compared with an extensive vegetated roof, has greater soil volume, supports a wider variety of plants (including shrubs and trees), and allows a wider variety of uses (including human access). The depth of the growing medium is an important factor in determining habitat value. The native or adapted plants selected for the roof should support the site’s endemic wildlife populations. (Adapted from Green Roofs for Healthy Cities)

Interior Floor Finish
all the layers applied over a finished subfloor or stairs, including stair treads and risers, ramps, and other walking surfaces. Interior finish excludes building structural members, such as beams, trusses, studs, or subfloors, or similar items. Interior finish also excludes nonfull spread wet coatings or adhesives.

Interior Wall and Ceiling Finish
all the layers comprising the exposed interior surfaces of buildings, including fixed walls, fixed partitions, columns, exposed ceilings, and interior wainscoting, paneling, interior trim or other finish applied mechanically or for decoration, acoustical correction, surface fire resistance, or similar purposes

Intermodal Facility
a venue for the movement of goods in a single loading unit or road vehicle that uses successively two or more modes of transportation without the need to handle the goods themselves

International Energy Agency (IEA)
An organization committed to energy policies around the world. The goal is to ensure a cost-effective and dependable renewable energy system for a country’s citizens through their commitment to energy security, economic development and environmental protection.

Interstitial Space
an intermediate space located between floors with a walk-on deck, often used to run the majority of the utility distribution and terminal equipment, thus permitting convenient installation, maintenance, and future modifications

Invasive Plant / Vegetation
nonnative vegetation that has been introduced to an area and that aggressively adapts and reproduces. The plant’s vigor combined with a lack of natural enemies often leads to outbreak populations. (Adapted from U.S. Department of Agriculture). Defined by Executive Order 13112 as “an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health.” Not all non-native species are considered invasive. Invasive species differ by region, and can be identified through local and state agencies. A list of regional agencies is provided at

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Kilowatt Hour (kWH)
A Kilowatt hour or kWH is a unit of energy typically used to describe electrical energy used in a home or appliance. There are 1,000 watts in a kilowatt.

Kyoto Protocol
A United Nations agreement signed in Kyoto, Japan in the 1990s. The agreement set country-targets for reduction of carbon emissions and created a method for offsetting (trading) carbon emissions.

Ladder Blocking
A method of framing that is used where interior partition walls meet and are reinforced by exterior walls. This eliminates unnecessary framing at these intersections.

a device emitting light in a fixture, excluding lamp housing and ballasts. Light-emitting diodes packaged as traditional lamps also meet this definition.

Lamp Life
the useful span of operation of a source of artificial light, such as bulbs. Lamp life for fluorescent lights is determined by testing three hours on for every 20 minutes off. For high-density discharge lamps, the test is based on 11 hours on for every 20 minutes off. Lamp life depends on whether the start ballast is program or instant. This information is published in manufacturers’ information. Also known as rated average life.

Land Trust
a private, nonprofit organization that, as all or part of its mission, actively works to conserve land by undertaking or assisting in conservation easement or land acquisition, or by its stewardship of such land or easements (Adapted from Land Trust Alliance)

Land-clearing debris and soil
materials that are natural (e.g., rock, soil, stone, vegetation). Materials that are man-made (e.g., concrete, brick, cement) are considered construction waste even if they were on site.

Landscape Water Requirement (LWR)
the amount of water that the site landscape area(s) requires for the site’s peak watering month

A toxic pollutant, typically found in older homes, that is a component of lead-based paint.

a label, defined by U.S. EPA regulations under the Safe Drinking Water Act, that allows small amounts of lead in solders, flux, pipes, pipe fittings, and well pumps

Lean Building
Maximum performance with minimum material usage- see advanced framing
technique use.

Least-Risk Pesticide
a registered pesticide in the Tier III (lowest toxicity) category, using the San Francisco Hazard Ranking system, or a pesticide that meets the requirements in the San Francisco Pesticide Hazard Screening Protocol and is sold as a self-contained bait or as a crack-and-crevice treatment used in areas inaccessible to building occupants. Rodenticides are never considered least-risk pesticides.

the acronym for Leadership in Energy and Environmental Design. The LEED program was developed by the U.S. Green Building Council (USGBC) as a green building rating system for rating new and existing commercial, institutional and high-rise residential buildings and even homes. It evaluates the overall environmental performance during the lifecycle of a building and provides a tangible methodology for analyzing the standards of a green building.

LEED is based on a 100-oint rating system with additional points available for Innovation in Design or Operations, Exemplary Performance, Pilot Credits and Regional Priority Credits. The available ratings are LEED Certified (40-49 points), LEED Silver (50-59 points), LEED Gold (60-79 points), LEED Platinum (80+ points).

LEED is administered by the USGBC, and the Green Business Certification Incorporated (GBCI) As of this writing, the current rating system standards are version four (v4) there are 5 different types of LEED certifications:
Building Design + Construction (LEED BD+C)
Interior Design + Construction (LEED ID+C)
Building Operations + Maintenance (LEED O+M)
Neighborhood Development (LEED ND)
LEED for Homes
USGBC is a 501c3 organization, more information can be found at

LEED for Homes
a building certification program that confirms the level of sustainability of a home’s construction. It involves four main steps: registering the project; verifying the milestones; reviewing it with a certified rater; and certification.

Level Spreader
A mechanism that manages storm water runoff by containing, filtering, and slowly releasing it back into a stream or water source. Consists of a forebay, channel, and buffer.

Lifecycle Assessment (LCA)
Reviews the environmental performance of a product or building over the course of its life, including financial costs, energy efficiency and maintenance requirements. The process includes an assessment of raw material production, manufacture, distribution and disposal. an evaluation of the environmental effects of a product from cradle to grave, as defined by ISO 14040–2006 and ISO 14044–2006

Life-Cycle Inventory
a database that defines the environmental effects (inputs and outputs) for each step in a material’s or assembly’s life cycle. The database is specific to countries and regions within countries.

Lifestyles of Health and Sustainability (LOHAS)
A marketplace promoting environmentally friendly products and services, social justice, personal development and sustainability for businesses and individuals.

Light-Emitting Diode Lamp (LED)
A technology that produces light by causing electrons to flow through the lamp and release energy in the form of light. LED lighting is very energy efficient using the least amount of power to generate desired units of light as compared to incandescent and fluorescent lighting technologies.

Light Fixture/Luminaire
A light system that is permanently fixed to the home, in the case of
fluorescent light fixtures, the fixture includes an integrated ballast. A compact fluorescent lamp (CFL) is not a light fixture.

Light Pollution
Light pollution comes from many sources, but generally from unshielded
lighting that allows light on a site to escape. Some lighting cannot be effectively reduced by shielding such as parking lot or street lights that reflect off of structures and bounce light away from the site. However, simple hooding of the “naked” light source directing the light to the ground or limiting its outward influence can significantly reduce light pollution.

Light Rail
transit service using two- or three-car trains in a right-of-way that is often separated from other traffic modes. Spacing between stations tends to be ½ mile or more, and maximum operating speeds are typically 40–55 mph (65–90 kmh). Light-rail corridors typically extend 10 or more miles (16 kilometers).

Light Trespass
obtrusive illumination that is unwanted because of quantitative, directional, or spectral attributes. Light trespass can cause annoyance, discomfort, distraction, or loss of visibility.

Living Building Challenge
Currently the world’s most stringent green building rating system operated by the International Living Future Institute. LBC go beyond other rating systems globally to require the attainment of 21 Imperatives including Net Positive Energy and Net Positive Water. Buildings, neighborhoods, renovations, or infrastructure (non-conditioned space) which meet this rigorous green building standard must achieve all corresponding imperatives. The program also recognizes project that gain Petal Certification for meeting a minimum of 4 of the imperatives. More information can be found at and by searching for the International Living Future Institute.

Load Shedding
an intentional action by a utility to reduce the load on the system. Load shedding is usually conducted during emergency periods, such as capacity shortages, system instability, or voltage control.

Load Controller
An outdoor computer installed next to your breaker panel and connected to the 220v appliances like A/C units, clothes dryers, water heaters, electric spa heaters, etc. It measures the usage of power in your home and controls peak demand energy usage by defaulting to a pre-set level. As demand increases, the load controller “sheds” (shuts off) lower priority appliances to maintain a user pre-set demand level.

Local Heat Island Effect
the incidence of higher air and surface temperatures caused by solar absorption and re-emission from roads, buildings and other structures.

Long-Term (secure) Bicycle Storage
bicycle parking that is easily accessible to residents and employees and covered to protect bicycles from rain and snow

Low Biocide
Paint that does not contain toxic additives, such as fungicide or pesticide.

Low-Cost Improvement
an operational improvement, such as a repair, upgrade, or staff training or retraining. In LEED, the project team determines the reasonable upper limit for low-cost improvements based on facility resources and operating budgets.

Low Emittance Doors/Windows
Building materials considered low emittance include window glass manufactured with metal-oxide coatings, housewrap materials, reflective insulation’s and other forms of radiant barriers. The Solar Heat Gain Coefficient (SHGC) ( can be used to measure how well a window blocks heat from sunlight.

Low Flow Toilet
A toilet that combines efficiency and high performance. Design advances enable these toilets to save water with no trade-off in flushing power. Such toilets often have the EPA’s WaterSense label.

Low Flow Fixture
A water consuming plumbing fixture with low consumption for example a faucet with a 0.5 gallon per minute (GPM) aerator installed to reduce the flow of water but not reduce water pressure a similar application would be a showerhead that consumes 2.0GPM or less.

Low-Impact Development (LID)
an approach to managing rainwater runoff that emphasizes on-site natural features to protect water quality, by replicating the natural land cover hydrologic regime of watersheds, and addressing runoff close to its source. Examples include better site design principles (e.g., minimizing land disturbance, preserving vegetation, minimizing impervious cover), and design practices (e.g., rain gardens, vegetated swales and buffers, permeable pavement, rainwater harvesting, soil amendments). These are engineered practices that may require specialized design assistance.

Low-pressure Drop Air Filters
High efficiency air filters with an extended surface, which allows for more filtration without an increase in horsepower.

Major Renovation
extensive alteration work in addition to work on the exterior shell of the building and/or primary structural components and/or the core and peripheral MEP and service systems and/or site work. Typically, the extent and nature of the work is such that the primary function space cannot be used for its intended purpose while the work is in progress and where a new certificate of occupancy is required before the work area can be reoccupied.

Makeup Water
water that is fed into a cooling tower system or evaporative condenser to replace water lost through evaporation, drift, bleed-off, or other causes

Manage (rainwater) On-Site
to capture and retain a specified volume of rainfall to mimic natural hydrologic function. Examples of rainwater management include strategies that involve evapotranspiration, infiltration, and capture and reuse.

Master Plan Boundary
the limits of a site master plan. The master plan boundary includes the project area and may include all associated buildings and sites outside of the LEED project boundary. The master plan boundary considers future sustainable use, expansion, and contraction.

Manufactured Locally
Generally this refers to products that are manufactured within a relatively short distance from the job site. Depending on the agency who is delineating the radius distance, the distance can vary yet is applicable to the Certification Standard being pursued. The primary intents are to be cognizant of long distance shipping and the energy expended and pollution created to move products from greater distances and further the support of local economies and regional economies within typically several hundred miles of the project site.

Mean Lumen Output
a measurement of a source’s emitted light derived from industry standards, taken with an instant-start ballast that has a ballast factor of 1.0 as measured at 40% of lamp life (except for T-5 lamps, which use a program-start ballast)

Medical Flexible (soft) Space
an area whose functions can be easily changed. For example, hospital administrative offices could be moved so that this soft space could be converted to a laboratory. In contrast, a lab with specialized equipment and infrastructure would be difficult to relocate.

Medical Furnishing
an item of furniture designed for use in health care. Examples include surgical tables; procedure, supply, and mobile technology carts; lifting and transfer aids; supply closet carts and shelving; and overbed tables.

MDF– Medium Density Fiberboard
An engineered panel product that can be used for such things as cabinets and wall panels while other MDF products can be shaped into moldings, ceiling tiles, flooring, interior doors and a variety of other uses. Exterior grades of MDF can be made into garage doors, sheds and other outdoor applications. A middle grade called “moisture resistant MDF” can be used externally but must be protected from water intrusion by sheltering.

Megawatt Hour (MWH)
A megawatt hour or MWH is a unit of energy typically used to describe electrical energy used in a home over the course of a year or when talking about energy use or generation on an industrial scale. There are 1,000 kilowatts in a megawatt.

Methane (CH4)
A greenhouse gas. Livestock production is a major source of methane emissions.

The Minimum Efficiency Reporting Value is used to describe worst case performance of
air filters.

Metering Control
a regulator that limits the flow time of water, generally a manual-on and automatic-off device, most commonly installed on lavatory faucets and showers

Mixed Paper
white and colored paper, envelopes, forms, file folders, tablets, flyers, cereal boxes, wrapping paper, catalogs, magazines, phone books, and photos

Modular and Movable Casework
shelving and cabinetry designed to be easily installed, moved, or reconfigured. In a retail setting, items that are movable but semi-permanently attached using mechanical fastening systems for operational use are considered furniture and not base building elements (e.g., a table or display bolted to the floor, or shelving attached to a wall).


Moisture Barrier
In building homes, it is vital to keep all unwanted water (including excessive water vapor) from getting into the floors, walls, or roof   of the house. Other terms commonly used are “waterproofing” and “vapor barrier.”  Asphalt-coated kraft paper, plastic sheeting, various membranes, specialty paints, and foam boards are common moisture barriers.

The moisture barrier is installed in multiple exterior locations (under the slab, on foundation walls, framed walls, and roof) to control and divert rain, dew, humidity, etc., as well as to resist vapor diffusion to the interior. It is vital that the barrier is continuous, or else water or vapor will have an opportunity to get inside where it can lead to mold and cause building materials to rot and fail.

Vapor retarders are also important. In cold climates, they are installed to diminish the diffusion of interior-sourced moisture vapor into the exterior walls and roof.

If a rainwater catchment system is installed, some of this water can be used for landscape irrigation.

Mounting Height
the distance between ground level (or the workplane) and the center of the luminaire (light fixture); the height at which a luminaire is installed.

Movable Furniture and Partitions
items that can be moved by the users without the need of tools or assistance from special trades and facilities management

Multi-Pane Windows
A window with more than one pane of glass. Dual pane windows are fairly common, and triple-pane windows can sometimes be found in cold climates.

Multi-Tenant Complex
a site that was master-planned for the development of stores, restaurants and other businesses. Retailers may share some services and common areas.

NAED code
a unique five- or six-digit number used to identify specific lamps, used by the National Association of Electrical Distributors

National Association of Home Builders (NAHB)
A trade association that helps promote the policies that make housing a national priority. Since 1942, NAHB has been serving its members, the housing industry, and the public.

National Green Building Standard (NGBS)
The National Green Building Standard (also known as the ICC-700) is the ANSI-approved, above code rating system for residential green construction. It can be applied to new and existing single and multi-family projects as well as land developments. Certification to the National Green Building Standard is provided by the NAHB Research Center. Further information can be found at

National Fenestration Rating Council (NFRC)
National organization that sets standards for windows and doors.

National Institute for Occupational Safety and Health, is a federal agency that conducts research in order to prevent work-related injury and illness.

The use of building techniques and natural materials that are based on locally available and renewable resources, and that are harvested or used in ways that ensure resources are not depleted or permanently damaged.

Native Plants
Plants that have evolved within their own ecological habitats, and are not invasive within their own native ranges. Native plants provide food and shelter to indigenous wildlife, stabilize shorelines and fields, ect.., growing in balance with surrounding plant and animal species.

Native Species
a species that originates in, and is characteristic of, a particular region and ecosystem without direct or indirect human actions. Native species have evolved together with other species within the geography, hydrology, and climate of that region.

Natural Refrigerant
a compound that is not manmade and is used for cooling. Such substances generally have much lower potential for atmospheric damage than manufactured chemical refrigerants. Examples include water, carbon dioxide, and ammonia.

Natural Resources Conservation Service (NRCS)
a U.S.-based soil survey that shows the boundaries of different soil types and special soil features on the site

Natural Site Hydrology
The topographical conditions and natural land cover function of water occurrence, distribution, movement, and balance

A landscaping method that uses native plants to conserve and create natural habitats that provides nurturing environments for wildlife.

Net Metering
A measurement and billing methodology that allows building’s electric meters to earn net benefit when they contribute electricity back to the grid when they generate more electricity (via solar PV and other renewable energy technologies) than they use. When electric meters turn backward, the customer receives kilowatt for kilowatt credit for their excess electricity generated. Without net metering, a second meter usually is installed to measure the electricity that flows back to the provider; the utility company purchases the power at a below-retail rate.

Net Usable Program Area
the sum of all interior areas in the project available to house the project’s program. It does not include areas for building equipment, vertical circulation, or structural components.

Net Zero Ready Home
Net Zero Ready Home is not an “official” term used within the Green Building industry but it is commonly used by homeowners for either a Net Zero home or a Zero Energy Ready Home or a home that is both.

Net Zero Home
A Net Zero Home is a home that produces at least as much energy as it consumes. “Technically” such a home does not need to be energy efficient but typically it is, so that less energy need be produced to offset the energy used.

Nitrogen Runoff
The harmful release of nitrogen into waterways. It negatively impacts aquatic wildlife by decreasing oxygen-levels in the water. Livestock and fertilizers are main sources.

Nitrous Oxide (N2O)
A greenhouse gas. Also known as laughing gas.

No-Disturbance Zones
an area that has no alterations or construction byproducts located within it, and has been designated to be preserved during construction.

No-Low VOC/Paints, Sealants, Varnish
Products that do not off-gas volatile organic compounds (VOCs). Using products with very little if any VOCs provides for better air quality.

Non-Regularly Occupied Space
an area that people pass through or an area used for focused activities an average of less than one hour per person per day. The one-hour timeframe is continuous and should be based on the time a typical occupant uses the space. For spaces that are not used daily, the one-hour timeframe should be based on the time a typical occupant spends in the space when it is in use.

Nonpotable Water
water that does not meet drinking water standards

No-Low VOC/Paints, Sealants, Varnish
Products that do not off-gas volatile organic compounds (VOCs). Using products with very little if any VOCs provides for better air quality.

Nutrient Loading
See nitrogen runoff.

OC (On Center) The distance between the center point of wood (usually 2×4) or other studs  used to frame a home. Conventional homes typically place studs ’16” OC’.  Green building sometimes places larger wooden stud (usually 2×6) ’24” OC’. This increases the space for insulation and the amount of wall backed by insulation. It also reduces the number of points in an outside wall where heat can be transferred through studs provide a lower amount of insulation value. Occupant Control a system or switch that a person in the space can directly access and use. Examples include a task light, an open switch, and blinds. A temperature sensor, photo sensor, or centrally controlled system is not occupant controlled. Occupiable Space an enclosed space intended for human activities, excluding those spaces that are intended primarily for other purposes, such as storage rooms and equipment rooms, and that are occupied only occasionally and for short periods of time (ASHRAE 62.1–2010) Occupied Space enclosed space intended for human activities, excluding those spaces that are intended primarily for other purposes, such as storage rooms and equipment rooms, and that are only occupied occasionally and for short periods of time. Occupied spaces are further classified as regularly occupied or nonregularly occupied spaces based on the duration of the occupancy, individual or multioccupant based on the quantity of occupants, and densely or nondensely occupied spaces based on the concentration of occupants in the space. Off-the-Grid A self-sufficient system of generating power that does not require connection to utility electricity grids.

On Demand Water Circulation Pump A water-conservation device that rapidly moves water from a water heater to fixtures.


On Demand Water heater A device that heats water rapidly as it is dispensed from the faucet. Eliminates the need for a conventional tank water heater.

On-Site Wastewater Treatment the transport, storage, treatment, and disposal of wastewater generated on the project site Ongoing Consumable a product that has a low cost per unit and is regularly used and replaced in the course of business. Examples include paper, toner cartridges, binders, batteries, and desk accessories. Also known as ongoing purchases. Open-Grid Pavement System pavements that consist of loose substrates supported by a grid of a more structurally sound grid or webbing. Pervious concrete and porous asphalt are not considered open grid as they are considered bounded materials. Unbounded, loose substrates do not transfer and store heat like bound and compacted materials do. Openable Window Area the free unobstructed area through the opening Operations and Maintenance (O&M) Plan a plan that specifies major system operating parameters and limits, maintenance procedures and schedules, and documentation methods necessary to demonstrate proper operation and maintenance of an approved emissions control device or system Oriented Strand Board (OSB) a manufactured wood structural panel generally cut to the size of standard plywood sheets and in various thicknesses. It is made by chipping very specific species of wood from smaller growth trees and “orienting” the grain of these chips into a pattern that provides optimum strength in the panel. The chips are then saturated with glue and pressed into production sizes. Ornamental Luminaire a luminaire intended for illuminating portions of the circulation network that also serves an ornamental function, in addition to providing optics that effectively deliver street lighting, and has a decorative or historical period appearance Outdoor Air Ventilation Intake A mechanical ventilation component of the HVAC system that draws in fresh air rather than recirculating and filtering air within a building. Owner’s Project Requirements (OPR) a written document that details the ideas, concepts, and criteria determined by the owner to be important to the success of the project Ozone Depletion Destruction of the earth’s ozone layer by the photolytic breakdown of chlorine and/or bromine containing compounds (chlorofluorocarbons or CFC’s) which catalytically decomposes ozone molecules. Commonly used as refrigerants, CFC’s have been found to damage the stratospheric ozone layer, creating holes and allowing harmful ultraviolet radiation to leak through.

Panelized Construction
Prefabricated building structural and exterior finished component elements

Passive House / Passivhaus
A Passive House (PH) is a home that requires very little energy for heating and cooling.
PH certification can be obtained through PHIUS, the Passive House Institute of the United States (PHIUS). There is a separate and somewhat different PH certification offered in the US by the international Passive House Institute (PHI).
To meet PHIUS PH standards, a home must meet the climate-adjusted and cost-optimized energy-use requirements of the program. PHIUS standards are more similar to Passivhaus than other domestic Passive House standards.

Passivhaus is the German term for passive house and the term used in Europe. Passivhaus standards are higher than some Passive House standards in the United States.

Passive Design
Building design that uses natural processes such as radiation, convection, absorption, conduction and thermal mass to support functions that aid in heating and cooling.

Passive Cooling/Heating
A building structure designed to increase ventilation and retention of heating/cooling within its building components.

Passive Solar (building)
A building / facility designed to collect, store and distribute the sun’s energy in winter (for heating) and to block summer sun (for cooling) to greatly reduce additional heating and air-conditioning needs. Passive solar design can be incorporated into any architectural style in any climate, but it requires careful site planning and selection of construction materials and building features.

Passive System
a passive system is one that requires no mechanical energy input in order to function. An example would be sun beams (solar energy) that enters through the windows which is stored in a thermal mass, such as concrete, water, or any heavy building material, then is re-radiated would be considered a passive heating.
Natural air circulation and daylighting are other examples of passive systems. The opposite of a passive system is an active system.

Peak Demand
the maximum electricity load demand at a specific measurable period of time

Peak Watering Month
the month with the greatest deficit between evapotranspiration and rainfall. This is the month when the plants in the site’s region potentially require the most supplemental water typically July a mid-summer month. (Sustainable Sites Initiative)

Fluorocarbons, sometimes referred to as perfluorocarbons or PFCs, are, strictly speaking, organofluorine compounds with the formula CxFy, i.e. they contain only carbon and fluorine, though the terminology is not strictly followed.

A method of community planning designed to create stable, productive communities. Permaculture uses land in a way that integrates human dwellings, plants, animals, soil and water, and it considers and works with the patterns found in nature.

Permanent Interior Obstruction
a structure that cannot be moved by the user without tools or assistance from special trades and facilities management. Examples include lab hoods, fixed partitions, demountable opaque full- or partial-height partitions, some displays, and equipment.

Permanent Peak Load Shifting
the transfer of energy consumption to off-peak hours, when demand for power is lower and energy is therefore less expensive

Permeable Pavement / Pervious Paving
Permeable Pavement is a paving material that allows the penetration of water, thus significantly reducing sheet flow runoff from storm water, whereas Pervious Paving is a paving solution that allows water to penetrate to the soil below, assisting in mitigating stormwater issues while concurrently recharging the groundwater stored resources at the site further reducing the need for irrigation water. There are a variety of permeable pavement methods including spaced pavers with soil infill and newer specialized asphalt and concrete applications that actually allow rainwater to pass through the surface and help to keep the water table from being depleted.

Persistent Bioaccumulative Toxic Chemical
a substance that poses a long-term risk to both humans and the environment because it remains in the environment for long periods, increases in concentration as it moves up the food chain, and can travel far from the source of contamination. Often these substances can become more potent and harmful to ecosystems the longer they persist. See U.S. EPA’s website on persistent bioaccumulative toxic chemicals,

Photovoltaic Panel (solar)
panels that are typically roof or ground mounted that collect solar energy and through the use of special solar voltaic cells, converts the energy to direct current electricity. A special controller called an inverter then converts this electricity to alternating current, making it usable in most residential and commercial applications. Electricity made in this fashion can be stored in batteries for later use, consumed as it is made to help offset the overall electrical use of a building, or placed into the commercial electrical grid for use in other locations. These panels only work when there is light, but can effectively produce electricity even on cloudy days.

Place of Respite (medical)
an area that connects healthcare patients, visitors, and staff to health benefits of the natural environment. (Adapted from Green Guide for Health Care Places of Respite Technical Brief)

Plug Load (or receptacle load)
the electrical current drawn by all equipment that is connected to the electrical system via a wall outlet(s).

Post-Consumer Recycled Content
generated by households or commercial, industrial and institutional facilities in their role as end users of a product that can no longer be used for its intended purpose that have been recovered after use for use in another product. Can aid in LEED Credit attainment if incorporated into finished materials to reduce virgin material content. This is distinguished from by-products of the manufacturing process that are recycled (pre-consumer recycling)

Post-Consumer Waste
Material(s) generated by households or by commercial, industrial and institutional facilities in their role as end-users of the product which can no longer be used for its intended purpose. This includes returns of materials from the distribution chain. Examples of this include construction and demolition debris materials collected through curbside and drop-off recycling programs, broken pallets (if from a pallet refurbishing company, not a pallet making company), discarded products (e.g. furniture, cabinetry and decking) and urban maintenance waste (leaves, grass, clippings and tree trimmings).

Potable Water
water that meets or exceeds U.S. Environmental Protection Agency drinking water quality standards (or a local equivalent outside the U.S.) and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems.

Power Distribution Unit Output
the electrical power from a device that allocates power to and serves information technology (IT) equipment. Power distribution unit (PDU) output does not include efficiency losses of any transformation that occurs within the PDU, but it can include downstream non-IT ancillary devices installed in IT racks, such as fans. If the PDU system supports non-IT equipment (e.g., computer room air-conditioning units, computer room air handlers, in-row coolers), this equipment must be metered and subtracted from the PDU output reading. The metering approach should be consistent with the metering required for the power usage efficiency (PUE) category (e.g., continuous consumption metering for PUE categories 1, 2, and 3).

Power Utilization Effectiveness (PUE)
a measure of how efficiently a data center uses its power; specifically, how much power is used by computing equipment rather than for cooling and other overhead

Powered Floor Maintenance Equipment
electric and battery-powered floor buffers and burnishers. It does not include equipment used in wet applications

Power Vented Exhaust
A design that uses active exhaust to pull combustion out of the home, combustion equipment with power venting can use indoor air as the combustion supply air.

Pre-Consumer Content
Previously referred to as Post-Industrial Content, this is material diverted from the waste stream during the manufacturing process. Excluded is reutilization of materials such as rework, regrind or scrap generated in a process that generated and capable of being reclaimed within the same process that generated it. Examples include planer shavings, plytrim, sawdust, chips, bagasse, sunflower seed hulls, walnut shells, culls, trimmed materials, print over-runs, over-issue publications and obsolete inventories. Can aid in LEED Credit attainment if incorporated into finished materials to reduce virgin material content.

Preferred Parking
the parking spots closest to the main entrance of a building (exclusive of spaces designated for handicapped persons). For employee parking, it refers to the spots that are closest to the entrance used by employees.

Premature Obsolescence
the wearing out or disuse of components or materials whose service life exceeds their design life. For example, a material with a potential life of 30 years is intentionally designed to last only 15 years, such that its remaining 15 years of service is potentially wasted. In contrast, components whose service life is the same as their expected use are utilized to their maximum potential.

Pressed Earthen Block
Pressed (or compressed) earthen block, similar to adobe, is made from a mixture of soil and aggregate with no chemical additives. Often machine manufactured at the construction site. Because there is relatively no quality control routine compared to other types of manufactured block, its use may be limited, especially in high seismic zones. Careful engineering will be required to use this material in structural applications.

Pressure Meter
A device for gauging the difference in air pressure between two spaces such as a garage and a crawl space.

Previously Developed
altered by paving, construction, and/or land use that would typically have required regulatory permitting to have been initiated (alterations may exist now or in the past). Land that is not previously developed and landscapes altered by current or historical clearing or filling, agricultural or forestry use, or preserved natural area use are considered undeveloped land. The date of previous development permit issuance constitutes the date of previous development, but permit issuance in itself does not constitute previous development.

Previously Developed Site
a site that, prior to the project, consisted of at least 75% previously developed land

Previously Disturbed
areas that have been graded, compacted, cleared, previously developed, or disturbed in any way. These are areas that do not qualify as ‘greenfield.’

Prime Farmland
land that has the best combination of physical and chemical characteristics for producing food, feed, forage, fiber, and oilseed crops and that is available for these uses, as determined by the U.S. Department of Agriculture’s Natural Resources Conservation Service (a U.S.-based methodology that sets criteria for highly productive soil). For a complete description of what qualifies as prime farmland, see U.S. Code of Federal Regulations, Title 7, Volume 6, Parts 400 to 699, Section 657.5.

Private Meter or submeter (water)
a device that measures water flow and is installed downstream from the public water supply meter or as part of an on-site water system maintained by the building management team

Process Energy
power resources consumed in support of a manufacturing, industrial, or commercial process other than conditioning spaces and maintaining comfort and amenities for building occupants of a building. It may include refrigeration equipment, cooking and food preparation, clothes washing, and other major support appliances. (ASHRAE)

Process Load (or unregulated load)
the load on a building resulting from the consumption or release of process energy (ASHRAE)

Process Water
water that is used for industrial processes and building systems, such as cooling towers, boilers, and chillers. It can also refer to water used in operational processes, such as dishwashing, clothes washing, and ice making.

Product (permanently installed building product)
an item that arrives on the project site either as a finished element ready for installation or as a component to another item assembled on-site. The product unit is defined by the functional requirement for use in the project; this includes the physical components and services needed to serve the intended function of the permanently installed building product. In addition, similar product within a specification, each contributes as a separate product.

Programmable Thermostat
A thermostat that allows homeowners to set the temperature at different levels at different times of day. For example, in winter, it could be set to be colder while occupants sleep and warmer as occupants awaken.

Project Electrical Load
The project load includes electric power delivered to metered customers, buildings, or loads within the project boundary, including the electric power required to centrally produce other energy delivered to customers, buildings, or loads within the project boundary such as chiller loads. This does not include parasitic loads such as transmission and distribution losses or reactive power compensation.

Public Transit Stop
A neighborhood or business area location where public transportation such as a bus can be accessed. To be effective, public transit stops need to be conveniently located so people do not have to walk long distances (generally less than 1/4 mile), weather protected in severe climates and inter-connected to either transit hubs or continuation lines.

Public Water Supply
a system for the provision to the public of water for human consumption through pipes or other constructed conveyances. To be considered public, such system must have at least 15 service connections or regularly serve at least 25 individuals. (Adapted from U.S. Environmental Protection Agency)

PV (Photovoltaic) See Solar Photovoltaic

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Radiant Barrier
A barrier, installed on the underside of roof sheathing in warm or hot climates to reflect some of the sun’s radiant heat energy so it does not enter the attic. Radiant barriers can also help prevent winter heat loss.

Radiant Floors – Hydronic
A popular and cost-effective choice that pumps heated water from a boiler through tubing underneath the floor. In some systems, the temperature in each room is controlled by regulating the flow of hot water through each tubing loop. This is done by a system of zoning valves or pumps and thermostats.

Radiant Heated Floors
A way to heat spaces using radiant energy that is emitted from a heat source. There are three types of radiant floor heat: radiant air floors (air is the heat-carrying medium); electric radiant floors; and hot water (hydronic) radiant floors.

Radiant Barrier Sheathing
Usually a foil faced plywood manufactured with proprietary methods that is used as the roof sheathing under the roofing material itself. The reflective surface of the material reflects heat away from the roof back through the shingles without significantly increasing the thermal load on the material, usually only 2 to 5 degrees. Other methods are rolled materials that are applied after the regular plywood or OSB sheathing is applied. Both materials can reduce attic and subsequent living area cooling loads significantly. Some manufacturers claim up to 97% effectiveness.

A radioactive gas that naturally vents from the ground. It can be dangerous if certain
areas of the home like basements are not properly sealed and ventilated. Areas with potentially elevated indoor radon levels can be found at

Rain/Freeze Sensors
Sensors prevent automatic sprinkler systems from watering during rain or cold weather.

Rain Garden
A shallow, constructed depression that is planted with deep-rooted native plants and grasses. It is located in the landscaping to receive runoff from hard surfaces, such as a roof, a sidewalk and a driveway. Rain gardens slow the rush of water from these hard surfaces and hold the water for a short period of time, allowing the water to naturally filter into the ground. Rain gardens help control storm water runoff.

Rain Water Catchment
Systems that harvest water during periods of rain. The water the can be saved and used during droughts.

Rainwater Harvesting
the capture, diversion, and storage of rain for future beneficial use. Typically, a rain barrel or cistern stores the water; other components include the catchment surface and conveyance system. The harvested rainwater can be used for irrigation.

Rammed Earth
Typically this is a soil-cement mixture that is rammed into forms to created walls that are generally 18 to 24 inches thick. The screened soil is usually engineered to assure the correct clay to sand ratio and is mixed with about 3% cement and sprinkled with water to provide cohesion and is compacted in 5 or 6 inch lifts to a relative density of around 120 to 130 pounds per cubic foot. Often concrete tie beams are incorporated to help stabilize the lateral strength of the material. The material is relatively labor intensive and the cost of a rammed earth house can be significant.

Raw Material
the basic substance from which products are made, such as concrete, glass, gypsum, masonry, metals, recycled materials (e.g., plastics and metals), oil (petroleum, polylactic acid), stone, agrifiber, bamboo, and wood

Reclaimed Lumber
Exactly as the term implies, this is lumber that is reclaimed by “deconstruction” of a building or structure. This lumber can be used for non-structural applications such as paneling and flooring and if re-graded can be use in structural applications. Major advantages include usually higher quality surface characteristics (it often came from tight grained old growth lumber), less cost than new lumber and reduction in landfill wastes (although it can easily be mulched). Major disadvantages are that it is fairly labor intensive to “clean up”, is often very hard to nail after many years of drying and may need to be predrilled, increasing installation cost.

Reclaimed Material
Also referred to as salvaged, reclaimed or reused material consists of building components (wood) that has been recovered from demolition site, but is used in its original state (i.e. not recycled).

The collection, processing, marketing and use of materials that were diverted or recovered from the solid waste stream.

Recycled Content Aggregate
Often concrete salvaged from demolition projects can be crushed and reused. Some can be introduced as a percentage of the aggregate in new concrete, while some can be used for roadbed underlayment. The actual use of the product is limited only to the imagination and structural requirements of the project. Use of the material also reduces the amount of new aggregate that must be mined from quarries and the associated environmental concerns associated with the operation.

Recycled Content Material
defined in accordance with the International Organization of Standards document ISO 14021 – Environmental labels and declarations – Self-declared environmental claims (Type II environmental labeling). As the name implies, many products can be manufactured using “post consumer” materials such as plastic, fiber, wood, glass and so on. Deconstruction of various structures can also produce a variety of “raw” materials to create new products from, everything from tiles to carpeting to composite flooring materials and beyond. Recycled content materials help to reduce the need for new raw materials and the accumulation and manufacturing processes involved.

Recycled Content Steel Studs
Most new light gauge metal studs are manufactured from a combination of new and recycled steel. About 66% of the total make up is recycled content.
Considering that the production of new steel is one of the highest embodied energy
manufacturing processes, the use of recycled steel not only redirects a continuously reusable resource, but significantly can reduce the impact on other environmental concerns. The use of light gauge metal studs on interior infill and demising walls lessens the amount of wood studs needed for construction; however more specialized skills are needed to install the material properly.

Reference Evapotranspiration Rate
the amount of water lost from a specific vegetated surface with no moisture limitation. Turf grass with height of 120 mm is the reference vegetation.

Reference Soil
a soil native to the project site, as described in Natural Resources Conservation Service soil surveys (or a local equivalent survey outside the United States), or undisturbed native soils within the project’s region that have native vegetation, topography, and soil textures similar to the project site. For project sites with no existing soil, reference soils are defined as undisturbed native soils within the project’s region that support appropriate native plant species similar to those intended for the new project.

The working fluids of refrigeration cycles that absorb heat from a reservoir at low temperatures and reject heat at higher temperatures.

Refurbished Material
an item that has completed its life cycle and is prepared for reuse without substantial alteration of its form. Refurbishing involves renovating, repairing, restoring, or generally improving the appearance, performance, quality, functionality, or value of a product.

Regularly Occupied Space
an area where one or more individuals normally spend time (more than one hour per person per day on average) seated or standing as they work, study, or perform other focused activities inside a building. The one-hour timeframe is continuous and should be based on the time a typical occupant uses the space. For spaces that are not used daily, the one-hour timeframe should be based on the time a typical occupant spends in the space when it is in use.

Regularly Used Exterior Entrance
a frequently used means of gaining access to a building. Examples include the main building entrance as well as any building entryways attached to parking structures, underground parking garages, underground pathways, or outside spaces. Atypical entrances, emergency exits, atriums, connections between concourses, and interior spaces are not included.

Regulated Load
any building end use that has either a mandatory or a prescriptive requirement in ANSI/ASHRAE/IES Standard 90.1–2010

Remanufactured Product

an item that has been repaired or adjusted and returned to service. A remanufactured product can be expected to perform as if it were new.

Renewable energy comes from sources which are essentially undiminished when used, or naturally replenished within a human timeframe (years or generations, rather than millions of years): wind, solar, hydro and geothermal are all examples of renewable energy. Fossil fuels (coal, oil, gas) are not renewable.
Renewable can also refer to building materials. Bamboo and pine for example can be grown, harvested and regrown in relatively short periods of time. They are “farmed” sources of wood. Certain types of wood (old growth type trees) take much longer to grow and harvesting can result in it becoming extinct as a species.

Renewable Energy
Renewable energy comes from sources which are essentially undiminished when used, or naturally replenished within a human timeframe (years or generations, rather than millions of years): wind, solar, hydro and geothermal are all examples of renewable energy. Fossil fuels (coal, oil, gas) are not renewable.

Renewable Energy Credit (REC)
a tradable commodity representing proof that a unit of electricity was generated from a renewable resource. RECs are sold separately from electricity itself and thus allow the purchase of green power by a user of conventionally generated electricity.

Renewable resources
Resources that are naturally replaced in a relatively short time: sun, wind, water, heat from the earth and biomass (plant-derived organic matter such as crop wastes, aquatic plants, bamboo and animal waste). Wood also is renewable, but it takes much longer to replace.

Resilient Home
A resilient home is one that has the capacity to maintain comfortable living conditions in the event of extreme situations: catastrophic weather, natural disasters, and extended utility service interruption.

Resilience can be understood in terms of energy production, water usage, and waste management.

Return Air Flow
The differing air pressure throughout a home can potentially cause problems with the building envelope, thus it is important to ensure that pressure is equalized throughout the home by allowing for vents (usually return of transfer grills) to “return” air.

materials: the reemployment of materials in the same or a related capacity as their original application, thus extending the lifetime of materials that would otherwise be discarded. Reuse includes the recovery and reemployment of materials recovered from existing building or construction sites. Also known as salvage.
water: the practice of using water that has already been used. The terms reclaimed water, reused water, and recycled water are used interchangeably in the water industry.

Reused Area
the total area of the building structure, core, and envelope that existed in the prior condition and remains in the completed design

Revenue-Grade Meter
a measurement tool designed to meet strict accuracy standards required by code or law. Utility meters are often called revenue grade because their measurement directly results in a charge to the customer.

A measure of thermal resistance (the number of watts that will be lost per square meter at a given temperature difference). The inverse of the U value (i.e. R=1/U).

Safe and Durable Roofing Materials
This can have a variety of definitions depending on one’s point of view but essentially these are roofing systems designed to last a significantly longer time to delay having to remove them and sending them to the landfill. Modern fiberglass roofing materials now carry warranties between 20 and 40 years. Of course slate, concrete and fired clay tiles can last significantly longer. Additionally, a safe roof generally refers to a fire safe roof and with modern roofing systems, various degrees of fire resistance ranging from class C to class A define the fire retardance of a roof. As a result of the firestorms of recent years, in which literally hundreds of homes were destroyed by flying brands from untreated wooded shingles and shakes, the State Fire Marshal has mandated that all roofs in California shall be at least Class B or better in fire retardance.

Salvaged Material
a construction component recovered from existing buildings or construction sites and reused. Common salvaged materials include structural beams and posts, flooring, doors, cabinetry, brick, and decorative items.

Sealed Combustion Fireplace / Woodstove
A sealed combustion fireplace or woodstove that gets its combustion air from outside of the home and exhausts 100 percent of the combustion by-products to the outside. This eliminates the likelihood of “backdrafting,” a situation in which combustion gases are pulled back into the home and cause health problems.

Sealed Crawl Space
A crawl space under a home that has been properly air sealed to conserve energy.

Sealed Ducting
A way to save energy and avoid moisture damage by repairing improperly installed ducts or by sealing the seams in ductwork.

Most air conditioners use electricity to produce cooling. The efficiency at which they
produce cooling is referred to as a SEER or EER number. SEER stands for Seasonal Energy
Efficiency Ratio, and is a ratio of the amount of cooling produced (BTU) divided by the amount of electricity (watts) used. The higher the SEER, the greater the efficiency.

Sequestration (carbon)
The process by which carbon dioxide is removed from the atmosphere by plants.

Service Life
the assumed length of time that a building, product, or assembly will be operational for the purposes of a life-cycle assessment

Shared Multi-occupant Space
a place of congregation, or where occupants pursue overlapping or collaborative tasks

Shell Space
an area designed to be fitted out for future expansion. Shell space is enclosed by the building envelope but otherwise left unfinished.

SHGC (Solar Heat Gain Coefficient)
A measure of how well a window blocks heat from sun as a fraction of the sun that enters the window. A lower SHGC is usually preferable.

Short-Term Bicycle Storage
non-enclosed bicycle parking typically used by visitors for a period of two hours or less.

Sick Building Syndrome
Acute health effects and physical discomfort apparently linked to time spent in a room or building. Also called “building-related illness,” this term is used when illnesses are attributed directly to airborne building contaminants. Symptoms may include headache; eye, nose or throat irritation; cough; dry or itchy skin; dizziness and nausea; difficulty concentrating; fatigue; and sensitivity to odors. Gases and vapors absorbed onto surfaces such as carpet, drywall, etc, and can later be re-emitted is a major contributor.

Simple Box Energy Modeling Analysis
(also known as “building-massing model energy analysis”) a simple base-case energy analysis that informs the team about the building’s likely distribution of energy consumption and is used to evaluate potential project energy strategies. A simple box analysis uses a basic, schematic building form.

Site Assessment
an evaluation of an area’s aboveground and subsurface characteristics, including its structures, geology, and hydrology. Site assessments typically help determine whether contamination has occurred and the extent and concentration of any release of pollutants. Remediation decisions rely on information generated during site assessments.

Site Master Plan
an overall design or development concept for the project and associated (or potentially associated) buildings and sites. The plan considers future sustainable use, expansion, and contraction. The site master plan is typically illustrated, with building plans (if applicable), site drawings of planned phased development, and narrative descriptions.

Site Preservation
Minimizing the disruption of a building on its surrounding environment (reusing existing structures on a site, rather than building upon unused land; or avoiding building on top of environmentally fragile land that could interfere with natural ecosystems).

Smart House
Electronic controls and sensors that regulate heating, cooling, ventilation, lighting, and appliance operation for energy conservation purposes.

Natural elements of a landscape such as a plant materials and the soil. Softscapes can include hard elements, such as rocks and stone.

Solar Garden/Community Renewable Energy System
shared solar array or other renewable energy system with grid-connected subscribers who receive credit for the use of renewables using virtual net metering (Adapted from

Solar Heat
Active solar space-heating systems consist of collectors that collect and absorb solar radiation combined with electric fans or pumps to transfer and distribute that solar heat. Active systems also generally have an energy-storage system to provide heat when the sun is not shining. The two basic types of active solar space-heating systems use either liquid or air as the heat-transfer medium in their solar energy collectors.

Solar Photovoltaics (PV)
These convert sunlight directly into electricity by using materials made from semiconductor materials. This material does not create any pollution, noise, or other environmental impact. Component cells which converts solar energy are typically amalgamated and assembled into a “solar panel” to attain a delivery voltage desired. The efficiency of these panels has increased greatly since they were first manufactured 40+ years ago. The manufacturing costs have gone down dramatically as well. This has made electricity from photovoltaic panels close to, equal to, or lower than some other common sources of energy. Solar PVs are also non-polluting, an example of clean energy.

Solar Pool Heater
A pool filtration system pumps that pumps pool water through a solar collector so that the collected heat is transferred directly to the pool water. Solar pool-heating collectors operate just slightly warmer than the surrounding air temperature and typically use inexpensive, unglazed, low-temperature collectors made from specially formulated plastic materials. Glazed (glass-covered) solar collectors are not typically used in pool-heating applications, except for indoor pools, hot tubs, or spas in colder climates. In some cases, unglazed copper or copper-aluminum solar collectors are used.

Solar Reflectance (SR)
the fraction of solar energy that is reflected by a surface on a scale of 0 to 1. Black paint has a solar reflectance of 0; white paint (titanium dioxide) has a solar reflectance of 1. The standard technique for its determination uses spectrophotometric measurements, with an integrating sphere to determine the reflectance at each wavelength. Determine the SR of a material by using the Cool Roof Rating Council Standard (CRRC-1).

Solar Reflectance Index (SRI)
a measure of the constructed surface’s ability to stay cool in the sun by reflecting solar radiation and emitting thermal radiation. It is defined such that a standard black surface (initial solar reflectance 0.05, initial thermal emittance 0.90) has an initial SRI of 0, and a standard white surface (initial solar reflectance 0.80, initial thermal emittance 0.90) has an initial SRI of 100. To calculate the SRI for a given material, obtain its solar reflectance and thermal emittance via the Cool Roof Rating Council Standard (CRRC-1). SRI is calculated according to ASTM E 1980. Calculation of the aged SRI is based on the aged tested values of solar reflectance and thermal emittance.

Solar Thermal
Solar thermal is simply solar energy in the form of heat. Solar thermal systems trap heat from the sun and heat or preheat water to heat the home or for hot water to be used in the home.
Solar thermal systems used on larger scales can be used to heat water, fluids, and other materials to very high temperatures which then can be used to generate steam and create electrical power.

Solar Rough-In
A method of installing plumbing and/or electrical systems that would allow a later addition of a solar photovoltaic or a solar hot water system.

Solar Water Heater
Heat from the sun that is absorbed using a Solar Thermal Collector and then transferred by pumps to a storage unit, which contains a heat exchanger to heat the domestic hot water within the collection tank.

Solar Window Screens
A mesh screen that is used to block insects as well as light and heat from the sun.
Solar Water Heating: Generally, this is a method of heating domestic water by allowing ground or rooftop mounted panels to collect solar rays as the water flows slowly through a series of small tubes. The heat transfer is then stored either in a potable drinking water vessel (your water heater) or introduced into a closed loop transport system to provide environmental space heating.

Sound-Level Coverage
a set of uniformity criteria that ensure consistent intelligibility and directionality of audible frequencies for all occupants within a space

Source Reduction
a decrease in the amount of unnecessary material brought into a building in order to produce less waste. For example, purchasing products with less packaging is a source reduction strategy.

Southern Exposure
In northern latitudes, a home exposed to the south can take advantage of collecting the sun’s energy either for production of electricity (photovoltaic), heating water, or as part of a passive solar design. The approach collects the sun’s energy in winter and offers natural lighting during the summer.

Spatial Daylight Autonomy (sDA)
a metric describing annual sufficiency of ambient daylight levels in interior environments. It is defined as the percentage of an analysis area (the area where calculations are performed, typically across an entire space) that meets a minimum daylight illuminance level for a specified fraction of the operating hours per year (i.e., the Daylight Autonomy value following Reinhart & Walkenhorst, 2001). The illluminance level and time fraction are included as subscripts, as in sDA300,50%. The sDA value is expressed as a percentage of area.

Speech Privacy
a condition in which speech is unintelligible to casual listeners (ANSI T1.523–2001)

Speech Spectra
the distribution of acoustic energy as a function of frequency for human speech

Spray Foam Insulation
Insulation that is sprayed into place and then expands to fill cavities. It acts as both an insulator and a sealant and is an alternative to the standard insulation bats. The two types of spray foam are open-cell (isocyanurate) and closed cell (polyurethane). Closed cell foams typically have a higher R-value than open-cell foam.

Storm Doors
A door that provides a pocket of air between the main door and the exterior door to improve insulation. Storm doors also protect the main door from wind, rain and ice.

Storm Windows
Single pane windows often installed on the interior of the main windows of home to improve insulation. When window replacement is cost prohibitive, adding storm windows can be an alternative for saving energy.

Straw Bale (construction)
a construction methodology developed to use special tightly bound straw bales as either bearing or infill walls in a variety of structures including homes. The straw bale system was an offshoot of the Nebraska straw house where their construction over a hundred years ago solved the basic problem of no lumber. The bales provide a substantial increase in insulation value but their installation can be rather labor intensive. The State of California has set down very specific criteria for construction of straw bale houses in the Health and Safety Code. All straw bale structures built in the city must meet Seismic Design Category D engineering requirements.

a transit service with small, individual rail cars. Spacing between stations is uniformly short and ranges from every block to ¼ mile, and operating speeds are primarily 10–30 mph (15–50 kmh). Streetcar routes typically extend 2–5 miles (3-8 kilometers).

Structural Bamboo
Bamboo as a construction material has many uses. Because the material is very hard it has recently found a niche as flooring material. However, the material is also very strong and with new methods of handling the material, structural uses of bamboo are finding their way into the construction industry. They can be derived into trusses, supporting poles and simple beams. However most building departments are not familiar with the capacity of the material and builders will have to supply significant engineering and detailing to satisfy plan check requirements.

Structural Components
elements carrying either vertical or horizontal loads (e.g., walls, roofs, and floors) that are considered structurally sound and nonhazardous

Structural Insulated Panel (SIP)
SIP is an acronym that stands for “structural insulated panel.”  SIPs are a sort of building material sandwich: an insulating foam center between two structural boards, often made out of OSB (a plywood-type product made from wood scraps.
These panels are often highly energy efficient. They eliminate heat leakage through framing materials and are relatively easy to make air-tight. They can also reduce construction time compared to  framed wall construction. They are suitable for use in high performance homes.

Sulfur Hexafluoride
A greenhouse gas.

In building, sustainable often refers to materials and processes that are resource-efficient. It can also refer to materials and processes that only used renewable resources. This means that they are environmentally responsible to build and cost-effective to operate.
Although definitions of sustainability can vary widely (see also “green”), a sustainable material or process is generally understood as one that exists in productive symbiosis with its environment.
Sustainable processes can also be understood as passive systems and renewable energy.

Awnings or window treatments which effectively block the sun’s heat.

Sustainable Deck Materials
Most of us are familiar with the wooden deck. However, new materials on the market are making a dramatic impact in the form of recycled content decking and railing systems. Usually manufactured with recycled plastics, wood chips and binders, the materials hold up well to hostile environments and generally outlast even naturally durable woods such as redwood and cedar. The intent is to select materials that are sustainable or easily replaced with limited effect on the ecology. These new materials are easily worked similar to wood, however are considerably more expensive. The trade off is the longevity of the material. While there are variations to the support structure under these materials, treated wood is still the primary structural system.

Sustainable Development
Development that sustains human needs and improves quality of life while making efficient and environmentally responsible use of natural, human and economic resources

Sustainable Flooring
Bamboo, cork or flooring that is made from reclaimed or rapidly renewable sources.

Systems Manual
provides the information needed to understand, operate, and maintain the systems and assemblies within a building. It expands the scope of the traditional operating and maintenance documentation and is compiled of multiple documents developed during the commissioning process, such as the owner’s project requirements, operation and maintenance manuals, and sequences of operation.

Tankless Water Heater
A system that delivers hot water at a preset temperature when needed, but without requiring the storage of water. The approach reduces or eliminates energy standby losses. Tankless water heaters can be used for supplementary heat, such as a booster to a solar hot water system, or to meet all hot water needs. Tankless water heaters have an electric, gas, or propane heating device that is activated by the flow of water.

Technical Advisory Sub-Committee
The TASCs rule on LEED Credit Interpretation Requests (CIRSs) and Innovative Design Requests (IDRs).

Technical Release (TR) 55
an approach to hydrology in which watersheds are modeled to calculate storm runoff volume, peak rate of discharge, hydrographs, and storage volumes, developed by the former USDA Soil Conservation Service

Thermal Bridge
Areas in a building envelope that have a high heat conductance lowering the average R value; conductive elements, such as a metal channel, allow heat energy to bypass a less conductive element, such as insulation.

Thermal Bridging
Many building materials are not good insulators (concrete, steel, wood) and act as paths for unwanted, high levels of heat flow, bypassing insulation and thereby wasting energy.  When such a material is not used carefully in the thermal envelope of a building, it creates a thermal bridge. BPC utilizes numerous new construction strategies to eliminate thermal bridges through the exterior floor, walls, and roof of a home.

Thermal Buffer
A gap between a space and its exterior used to reduce the heating/cooling load.

Thermal By-pass
An opening between spaces that air can move through, thereby violating air tightness.

Thermal Emittance
the ratio of the radiant heat flux emitted by a specimen to that emitted by a blackbody radiator at the same temperature (adapted from Cool Roof Rating Council)

Thermal Envelope
The thermal enclosure created by the building exterior and insulation. Improving the thermal envelope is one of the most important aspects to creating an energy
efficient buildings.

Thermal Flywheel
A space that collects heat then releases it in a continuous pattern.

Three-Year Aged SRI
or SRI value a solar reflectance or solar reflectance index rating that is measured after three years of weather exposure

Tight Construction
The elimination of gaps and holes in a building’s exterior through proper air sealing and ventilation. It reduces waste and makes a home more energy efficient.

Time-of-Use Pricing
a utility provider initiative in which customers pay higher fees to use utilities during peak demand time periods and lower fees during off-peak time periods

Title 24
Title 24 is contained in the California Code of Regulations (CCR) and is the embodiment of most of the construction and energy conservation requirements for the state. All cities and counties are mandated to enforce the requirements of Title 24.

The uppermost layer of soil with high levels of nutrients and organic matter. Healthy topsoil is essential for the survival of trees and plants.

Toxic (substance)
Any material or waste product, which can cause injury if inhaled, swallowed, or absorbed through the skin.

Tree/Plant Preservation Plan
A formal assessment of the lot and a development of a landscaping plan that seeks to preserve the most trees and native plants. This is important to do as one of the first steps in the design process to ensure the developed area takes into account the preservation plan.

Treated Wood
-CCA – Chromated Copper Arsenate. As the name implies the chemicals used to treat wood to prevent attacks by wood destroying organisms such as boring insects, fungi and dry rot contains arsenic, a rather nasty poison. Since December 31, 2003, the distribution of -CCA has been severely limited and is generally not available to the average homeowner anymore once existing stocks are depleted. It can still be manufactured for very specific commercial applications such as underwater saltwater pilings and cross member materials, but not for the decking, above water bracing or railings.
-ACQ -Alkaline Copper Quaternary (or Quat). This method of treatment uses copper as the primary active ingredient. While the material is effective for direct contact and above ground protection, it is highly corrosive to fasteners and fittings and special precautions must be taken in the selection (usually hot dipped galvanized or stainless steel) and the handling of the material.
-CA-Copper Azole. Like ACQ, the primary active ingredient is copper. While not quite as corrosive as ACQ, the material does have a tendency to migrate into the soil. Again special care in selection of fasteners and handling is required.
-DOT-Disodium Octaborate Tetrahydrate. DOT or simply borate or boron preserved wood is the least corrosive of the treatments. The material is intended for interior or protected use only and must be protected from direct water exposure which can leach the material out of the wood. Protected in dry conditions, the borates will migrate into the wood even deeper than the initial pressure injection application over time. The material is very effective against many wood pests including the voracious Formosan termite.

Trombe Wall
Also referred to as a “solar wall”, a Trombe wall consists of an 8-to-16-inch-thick masonry wall on the south side of a house. A single or double layer of glass is mounted about 1 inch or less in front of the wall’s surface. Solar heat is absorbed by the wall’s dark-colored outside surface and stored in the wall’s mass, where it radiates into the living space.

TXV (Thermostatic Expansion Valve) – (also TEV):
A TXV installed on an air conditioning system can dramatically improve the efficiency of the unit. When cooling demand is high, the valve opens up and lets more coolant pass through the indoor coils. When demand is low, the valve closes to reduce the refrigerant flow. AC units not equipped with TXV’s have either a fixed orifice or capillary tube system. Because they are not very efficient, they are generally not sold in California, since they cannot meet the CA Energy Commission requirements.

USDA Organic
the U.S. Department of Agriculture’s certification for products that contain at least 95% ingredients (excluding water and salt) produced without synthetic chemicals, antibiotics, or hormones. Any remaining ingredients must consist of USDA-approved nonagricultural substances or agricultural products that are not commercially available in organic form.

US Department of Energy (DOE)
While to DOE has many areas of responsibility, relative to Green Homes, the DOE has a program called Zero Energy Ready Homes with set standards for homes, that with a modest solar array (added when the home is built or after) are capable of being Net Zero Homes, essentially producing as much clean energy as it may pull from the power grid.

US Green Building Council (USGBC)
A 501c3 non-profit organization dedicated to sustainable building design and construction. USGBC is the developer of the LEED building rating system whose mission is to accelerate the adoption of green building practices, technologies, and standards.

U Value (U-Factor)
A measure of how well heat is transferred by the entire window – the frame, sash and glass – either into or out of the building. U-value is the opposite of R-value.
The lower the U-factor number, the better the window will keep heat inside a home on a cold day.

Undercover Parking
vehicle storage that is underground, under deck, under roof, or under a building. This strategy reduces Heat Island Effect, keeps automobile interior temperatures cooler in summer and can contribute to associated credits within the LEED Green Building Rating Systems.

Uninterruptible Power Supply (UPS)
a battery back-up unit that provides electrical energy to critical components of a building for example the information technology (IT) equipment functioning during a power outage. UPS output does not include efficiency losses from the unit itself but does include losses from downstream electrical distribution components, such as power distribution units, and it may include non-IT ancillary devices installed in IT racks, such as fans. If the UPS system supports non-IT equipment (e.g., computer room air-conditioning units, computer room air handlers, in-row coolers), this usage must be metered and subtracted from the UPS output reading. The metering approach should be consistent with the metering required for the power usage efficiency (PUE) category (e.g., continuous consumption metering for PUE categories 1, 2 and 3).

Universal Waste
hazardous items that are easily purchased and commonly used. Examples include batteries, pesticides, mercury-containing equipment, and light bulbs. See

Unoccupied Space
an area designed for equipment, machinery, or storage rather than for human activities. An equipment area is considered unoccupied only if retrieval of equipment is occasional.

Upstream Equipment
a heating or cooling system or control associated with the district energy system (DES) but not part of the thermal connection or interface with the DES. Upstream equipment includes the thermal energy conversion plant and all the transmission and distribution equipment associated with transporting the thermal energy to the project building or site.

Urban Infill
Redevelopment of sites, in the core of metropolitan areas, for commercial and residential purposes.

Urban Heat Islands
Dark-colored surfaces absorb heat from the sun more than light-colored surfaces. In urban areas, a combination of dark surfaces and a lack of shade intensify this effect. One solution is the use of lighter-colored materials in building construction. The use of well-placed vegetation to increase shade or green roof systems can also minimize these effects and increase energy efficiency.

Vertical Illuminance
illuminance levels calculated at a point on a vertical surface, or that occur on a vertical plane

Vegetated Roof
A roof partially or fully covered by vegetation. By creating roofs with a vegetated layer, the roof can counter-act the heat island effect as well as provide additional insulation. (See Green Roof)

Vision Glazing
the glass portion of an exterior window that permits views to the exterior or interior. Vision glazing must allow a clear image of the exterior and must not be obstructed by frits, fibers, patterned glazing, or added tints that distort color balance.

Volatile Organic Compound (VOC)
Many of the products that we buy are made with materials that off-gas VOC’s usually in the form of formaldehyde gas, a by-product of hydrocarbon based materials. Building materials such as particle board, plywood, adhesives, paints, varnishes, carpet, drapes and furniture are often made with formaldehyde products. Other sources include some you may not think of like tobacco, burning gas, perfume, cleaning agents, hairspray and even copy and printing machines. Degrees of exposure to VOC’s can cause everything from mild symptoms like irritated eyes, ears and throat to more severe reactions like wheezing and lung, memory and anxiety problems. By using low-VOC products, exposures are reduced and indoor air quality is improved.

Walk-Off Mats
Interior mats designed to reduce dust and debris. Walk off mats should be placed at the entrances and allow for a few strides on the may to be most effective.

Walking Distance
the distance that a pedestrian must travel between origins and destinations without obstruction, in a safe and comfortable environment on a continuous network of sidewalks, all weather-surface footpaths, crosswalks, or equivalent pedestrian facilities. The walking distance must be drawn from an entrance that is accessible to all building users.

Waste Diversion
a management activity that disposes of waste through methods other than incineration or landfilling. Examples include reuse and recycling.

the conversion of nonrecyclable waste materials into usable heat, electricity, or fuel through a variety of processes, including combustion, gasification, pyrolization, anaerobic digestion, and landfill gas (LFG) recovery

water that has been used for a purpose and conveyed by building plumbing systems toward a point of treatment and disposal. Wastewater from buildings can be classified as graywater, blackwater, or process wastewater.

Water Body
the surface water of a stream (first-order and higher, including intermittent streams), arroyo, river, canal, lake, estuary, bay, or ocean. It does not include irrigation ditches.

Water Budget
a project-specific method of calculating the amount of water required by the building and associated grounds. The budget takes into account indoor, outdoor, process, and makeup water demands and any on site supply including estimated rainfall. Water budgets must be associated with a specified amount of time, such as a week, month, or year and a quantity of water such as kGal, or liters.

Water Efficiency (products)
components, such as low-flow water fixtures, that use less water than traditional products, while still sustaining the same performance.

Water Footprint
An estimation of the amount of water used.

Waterless Urinal
a plumbing fixture having a water flush with a trap that contains a layer of buoyant liquid that floats above the urine, blocking sewer gas and odors

Watershed Protection
An environmental movement that monitors our daily actions and their effects toward the conservation, development, utilization and proper disposal of water in order to maintain safe and effective drainage for the various water systems surrounding us.

A unit of measurement used for energy. Often it is used as the unit of measurement to describe how much electricity is used by an appliance.

an area that is inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances does support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas, but exclude irrigation ditches unless delineated as part of an adjacent wetland.

Whole-Building Design
The integration of a building’s systems to maximize environmental and financial functioning by considering energy systems, building materials, design methods, site preservation, and indoor air quality so that a structure can run at its maximum efficiency.

Whole House Fan
Essentially a large fan that draws hot air out of a building and replaces it with cooler exterior air as opposed to attic fans that only remove the hot air from the attic. Compared to an air conditioner that can draw up to 6000 watts, whole house fans use about the same amount of electricity as a couple of light bulbs, or around 120 watts for smaller units up to about 700 watts for larger units. New homes of especially tight construction may need to have barometric vents installed a distance away from the exhaust intake to prevent negative pressure problems in the house that could have an adverse effect on fuel burning appliances (or simply open a couple of screened windows). A good whole house fan can reduce the interior temperature of a house by 10 to 15 degrees within about 20 minutes as well as create a “sensible” feeling that the moving air is cooler.

Wind Power
Power supplied by an onsite wind turbine.

Wind Turbine
A mechanical system that “captures” wind to generate electrical power. Most commonly wind turbines are generally a very tall, slender device that looks like a huge fan with skinny blades that converts wind into usable electricity in locations where sufficient wind speed is reliably found. Wind turbines are generally less cost effective compared to other renewable energy options. Their greatest efficiency and power output comes at larger scales so they are usually built and maintained by utilities or other large companies. In an ideal installation surplus electricity is stored in a battery system for future use, or provided to the utility grid.

plant-based materials that are eligible for certification under the Forest Stewardship Council. Examples include bamboo and palm (monocots) as well as hardwoods (angiosperms) and softwoods (gymnosperms)

a landscaping design methodology that utilizes locally based species which requires less maintenance by exemplifying good planning, efficient irrigation processes, soil improvement, easily foliage conservation, and good maintenance.

Yard Tractor a vehicle used primarily to facilitate the movement of truck trailers and other types of large shipping containers from one area of a site to another. It does not include forklift trucks. Also known as terminal tractor, yard truck, utility tractor rig, yard goat, or yard hustler.
Zero-Energy Homes Houses that do not use any energy from the utility grid because they have been designed to produce as much energy as they consume. The home’s design marries optimal energy efficiency to renewable energy resources, such as solar electricity, to maximize the effectiveness of both. Zero Energy Ready Home This is a term (and certification program) used by the DOE (Department of Energy) that refers to newly constructed homes or whole house remodels that are so energy efficient that the energy required for space heating, hot water, and other household needs could be entirely satisfied by renewable energy sources. Prior to being known as a Zero Energy Ready Home, the certification program was called DOE Challenge Homes. Zero Lot Line Project a plot whose building footprint typically aligns or nearly aligns with the site limits Zoned Air-Conditioning Systems with separate thermostat controls in different parts of a structure that allow for independent temperature control of each area. Zoned Heating Heating systems with separate thermostat controls in different parts of a structure to allow for independent temperature control in each area.