Biodiversity is the variety of life in all forms, levels, and combinations, including ecosystem diversity, species diversity, and genetic diversity.

Brownfield is real property whose use may be complicated by the presence or possible presence of a hazardous substance, pollutant, or contaminant.

Building Footprint is the area on a project site used by the building structure, defined by the perimeter of the building plan. Parking lots, landscapes, and other nonbuilding facilities are not included in the building footprint.

Carbon dioxide (CO2) levels are an indicator of ventilation effectiveness inside buildings. CO2 concentrations greater that 530 ppm above outdoor CO2 conditions generally indicate inadequate ventilation. Absolute concentrations of CO2 greater than 800 to 1000 ppm generally indicate poor air quality for breathing.

Cogeneration is the simultaneous production of electrical or mechanical energy (power) and useful thermal energy from the same fuel/energy source such as oil, coal, gas, biomass, or solar panels. Conventionally, heat is emitted through cooling towers or flue gas is lost, but cogeneration makes use of that heat.

Commissioning (Cx) is the process of verifying and documenting that a building and all of its systems and assemblies are planned, designed, installed, tested, operated, and maintained to meet the owner’s project requirements.

Commissioning Authority (CxA) is the individual designated to organize, lead and review the completion of the 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.

Commissioning Process is a systematic quality-focused effort to ensure that building systems are designed, specified, procured, installed, and functioning in accordance with the owner’s intent. The process uses planning, documentation, and verification of testing to review and oversee the activities of both designer and constructor.

Commissioning Team includes those people responsible for working together to carry out the commissioning process.

Curtain walls protect a building from air and water infiltration. A glass curtain wall allows daylight in while reducing infiltration. A glass curtain wall can be fitted with operable windows or vents.

Daylighting is letting natural light into a space through glazing with the intent of reducing or eliminating electric lighting. By using sunlight, daylighting creates a stimulating, less artificial, more productive environment for building occupants.

Ecosystem is a basic unit of nature that includes a community of organisms and their nonliving environment linked by biological, chemical, and physical processes.

Emissions reduction reporting is the calculating, tracking, and documenting of the greenhouse gas emissions that result directly from energy use and other operations of a building.

Emissivity is a ratio of radiation a surface gives off. Using products with low emissivity—for example white roofs rather than black roofs — reduces the heat island effect (see below) whereby urban landscapes become significantly warmer than surrounding rural landscapes.

Energy Star ® rated products meet the energy efficiency guidelines specified by the U.S. Environmental Protection Agency and the U.S. Department of Energy.

Fly ash is a solid byproduct of electric power generation often added to concrete and cement that improves durability, and reduces the need for other materials by making use of a byproduct.

Formaldehyde is a naturally occurring volatile organic compound (VOC, see below), but it is highly carcinogenic and an irritant in high concentrations causing headaches, dizziness, mental impairment, and other symptoms.

Fossil fuels (mainly coal, oil, and natural gas) are decayed fossils. The combustion of fossil fuels releases carbon dioxide into the atmosphere, contributing to the greenhouse effect and climate change.

FSC Certified wood is certified by the Forest Stewardship Council, a third-party certifier of environmentally, socially responsible, economically viable wood. Entire forests can be certified and wood can be chain-of-custody certified, which means the product is tracked from forest to consumer.

Fuel cells convert chemical energy into electricity and hot water without using a combusted fuel source

Geothermal energy systems, not to be confused with ground-source heat pumps (see below), produce energy in regions with specific geological conditions where heat escapes from the earth’s core at temperatures high enough to create steam that can be used to power a turbine. (Such conditions are uncommon in the eastern United States.)

The Gravity-Film Heat Exchanger (GFX) is a technology that uses the heat from hot water going down drains to preheat water in a hot water tank.

Graywater is untreated household wastewater (see below) that has not come into contact with toilet waste, including water from sinks, showers, dishwashers, and washing machines. Some local codes may count dishwasher and kitchen sink wastewater as blackwater.

Green is an adjective now commonly used to describe something or someone that is environmentally conscious or friendly, sustainable, or has positive environmental attributes, effects, or objectives.

Green power is a synonym for renewable energy or renewable energy credits.

Green –e is a program established by the Center of Resource Solutions to both promote green electricity products and provide consumers with a rigorous and nationally recognized methods to identify those products.

Greenwashing is the unjustified appropriation of environmental virtue by a company, an industry, a government, a politician or even a non-government organization to create a pro-environmental image, sell a product or a policy, or to try and rehabilitate their standing with the public and decision makers after being embroiled in controversy.

Ground-source heat pumps (GSHP), often mistakenly called geothermal heat pumps, should not to be confused with geothermal energy systems (see above). A GSHP circulates liquid through an underground loop, bringing warmer or cooler temperatures to a building depending on the season. Because it uses the constant temperature (45-50 degrees Fahrenheit) of the earth at 5-6 feet below ground, heating and cooling costs are reduced. A GSHP uses electricity for the pump, but the system is 300-400% efficient, and the payback period is generally 3-5 years. These can be installed anywhere.

Gypsum is a mineral used in drywall. Mining of gypsum disrupts habitats, uses energy and causes pollution. Synthetic gypsum is made with fly ash (see above), a byproduct of manufacturing and energy generating processes, which reduces the need for mined material. Recycled gypsum drywall is made with reclaimed drywall and waste from drywall manufacturing.

Heat island effect occurs when warmer temperatures are experienced in urban landscapes compared to adjacent rural areas as a result of solar energy retention on constructed surfaces. Principal surfaces that contribute to the heat island effect include streets, sidewalks, parking lots and buildings. Trees, green roofs (see above), reflective coloring, vegetated landscaping, and bodies of water mitigate the heat island effect.

Hybrid vehicles use a gasoline engine to power an electric generator. The generator, together with storage batteries, powers electric motors that drive the vehicle’s wheels. Hybrid vehicles use less gasoline and produce less pollution compared to conventional vehicles of similar size.

Impervious surfaces are mainly constructed surfaces that are impenetrable by water and contribute to storm water runoff and the heat island effect. Pervious or porous surfaces allow some water infiltration, thereby reducing runoff.

LEED stands for Leadership in Energy and Environmental Design, a rating system designed by the U.S. Green Building Council.

LEED CI: LEED for Commercial Interiors is a benchmark for the tenant improvement market that gives the power to make sustainable choices to tenants and designers.

LEED CS: LEED for Core & Shell aids designers, builders, developers and new building owners in implementing sustainable design for new core and shell construction.

LEED for Healthcare promotes sustainable planning, design and construction for high-performance healthcare facilities.

LEED for Homes promotes the design and construction of high-performance green homes.

LEED for Neighborhood Development integrates the principles of smart growth, urbanism and green building into the first national program for neighborhood design.

LEED for Retail recognizes the unique nature of retail design and construction projects and addresses the specific needs of retail spaces.

LEED for Schools recognizes the unique nature of the design and construction of K-12 schools and addresses the specific needs of school spaces.

LEED NC: LEED for New Construction and Major Renovations is designed to guide and distinguish high-performance commercial and institutional projects.

LEED OM: LEED for Existing Buildings: Operations & Maintenance provides a benchmark for building owners and operators to measure operations, improvements and maintenance.

LEED Rating Systems

Louvers are frames with horizontal and vertical slats that allow light and air in while keeping out direct sunlight, rain, and noise.

Low-E glazing on windows is a low-emitting coating made of metal or metallic oxide layers that prevent heat and ultra-violet rays from passing through the glass. Low-E glazing prevents heat gain in the summer and heat loss in the winter.

Low-flow fixtures are plumbing fixtures that use less water than average fixtures. Low-flow toilets use no more than 1.6 gallons per flush compared to the traditional 3.5 gallons per flush.

Low-iron windows provide 5% higher visible light transmittance than ordinary clear glass windows.

Medium-Density Fiberboard, (MDF), an engineered wood product made of softwood fibers, wax, and resin and formed into panels with the use of heat and pressure.

Microturbines are small rotary engines (usually fueled by natural gas) that provide on-site electricity generation.

Minimum Efficiency Reporting Value, (MERV), is a rating from 1 to 16 that measures a filter’s efficiency. A higher MERV means the air filter is more efficient at removing particles.

Native plants have adapted to a specific area over a defined time period and are not invasive. In the US, the term often refers to plants growing in a region prior to the arrival of European settlers.

Non-potable water is not fit for consumption without treatment that meets or exceeds EPA drinking water standards. Graywater and rainwater are non-potable waters that can be used in toilets, for washing cars, etc. and the use of either reduces the demand for potable water, conserving this vital resource.

Occupancy sensors are devices that shut off lights automatically when rooms are unoccupied.

On-site wastewater treatment uses localized treatment systems to transport, store, treat and dispose of wastewater volumes generated on the project site.

Open-grid paving systems are a form of pervious paving that allows space for vegetation; the vegetations’ evapotranspiration reduces the heat island effect caused by pavement.

Pervious or porous surfaces allow water infiltration, which reduces runoff (see below). One example is an open-grid paving system, which allows space for vegetation – the vegetations’ evapotranspiration reduces the heat island effect (see above) caused by pavement.

Photovoltaic systems (also known as solar panels) use sunlight to create electricity. Solar hot water systems, however, use sunlight to heat water directly.

Potable water is water suitable for drinking and supplied from wells or municipal water systems.

Rainwater is water accumulated from precipitation.

Rainwater catchment systems or cisterns catch and store rainwater for uses such as irrigation, plumping, or cooling towers, thereby reducing stormwater runoff.

Rapidly renewable materials and products are materials considered to be agricultural products, both fiber and animal, that take 10 years or less to grow or raise, and are harvested in an ongoing and sustainable fashion. Examples include bamboo, cork, wool, cotton, agrifiber, linoleum, wheatboard, and strawboard.

Reclaimed water is wastewater that has been treated and purified for reuse.

Recommissioning applies to buildings that were previously commissioned as part of new construction or buildings covered by existing building commissioning.

Recyclable materials can be easily recycled and reused in the future.

Recycled materials are made of previously used resources or products (as opposed to virgin materials).

Renewable energy, or green power, comes from natural resources that can be naturally (and relatively quickly) replenished, such as sunlight, wind, rain, tides, biomass, biofuels, geothermal, and ground source heat.

Renewable Energy Credits/Certificates, (RECs), are tradable commodities representing renewable energy. RECs are purchased in addition to grid electricity to offset non-renewable energy used with renewable sources. RECs fund renewable energy sources and contribute renewable energy to the national grid, thereby reducing fossil fuel based energy production. Rocs purchased to achieve LEED points must be certified Green-e (a third-party certifier) or meet equivalent standards. Green power is another term often used for Rocs.

Runoff is a term used to describe when soil is infiltrated to full capacity with excess water, from rain, snowmelt, or other sources. This is a major component of the water cycle. When runoff flows along the ground, it can pick up soil contaminants such as petroleum, pesticides (in particular herbicides and insecticides), or fertilizers that pollute water sources.

Sedum is a genus of plants of the family Crassulaceae. These hardy, succulent plants are preferable to grass on green roofs because they absorb and retain water, reducing runoff and the need for watering.

Sky glow is caused by stray light from unshielded light sources and light reflecting off surfaces that then enter the atmosphere and illuminate and reflect off dust, debris, and water vapor. Sky glow can substantially limit observation of the night sky, compromise astronomical research, and adversely affect nocturnal environments.

Slag is a by-product of smelting ore to purify metals, often used in concrete and to improve durability. Using slag both makes use of a byproduct and reduces the need for other materials in cement.

Solar panels can refer to either photovoltaic systems (see above), which produce electricity from sunlight, or solar hot water systems, which heat water directly with sunlight. In a solar hot water system, water or antifreeze is circulated through a closed loop system and preheats a tank of water.

Stormwater is water that accumulates during precipitation rather than soaking into the ground.

Stormwater detention systems regulate and control runoff by slowing the rate of discharge to reduce impacts downstream. Stormwater retention systems store water indefinitely, until it is lost through percolation, evaporation, or is taken up by plants.

Stormwater runoff is a cause of pollution; water running off of impervious surfaces (see above) accumulates pollutants (such as gasoline, fertilizers, pesticides, etc.) and brings them into water bodies. Stormwater runoff also erodes soil and waterways. Pervious surfaces (see above), stormwater detention systems (see below), or rainwater catchment systems (see above) reduce stormwater runoff.

Thermal energy storage technologies are used for storing energy in a thermal reservoir for later use. For cooling, ice is produced at night to provide daytime cooling, thereby reducing peak daytime electricity demands. For heating, solar collectors are most commonly used to gather heat, which is then stored for later use.

Under-floor displacement air ventilation systems diffuse air from the floor rather than the ceiling. This system saves ten percent more energy than a traditional ceiling-based system, reduces ductwork lengths and sizes, and allows for individual vent control.

Volatile Organic Compounds, (VOCs), are often found in carpets, paints, sealants, etc. VOCs contribute to indoor air pollution and are a health hazard.

Wastewater is water that has been used so that it is no longer potable. Wastewater can be classified as graywater or blackwater. Rainwater and stormwater are other types of non-potable water. See definitions.

Waterless urinals use no water, but instead replace the water flush with a specially designed trap that contains a layer of buoyant liquid that floats above the urine layer, blocking sewer gas and urine odors from the room.

Wave and Tidal Power Systems capture energy from waves and the diurnal flux of tidal power. The captured energy is commonly used for desalination, water pumping, and electricity generation.

Wind power is a form of renewable energy generated by wind spinning turbines.