Green Building Terms

Active solar – A system using mechanical devices (pumps, fans, etc.) that transfers collected heat to the storage medium and/or the end-use. [4]
Adaptive Reuse – Renovation of a building or site to include elements that allow a particular use or uses to occupy a space that originally was intended for a different use. [4]
Advanced Framed Ceiling – Advanced framing assumes full and even depth of insulation extending to the outside edge of exterior walls. [2]
Advanced Framed Walls – Studs framed on 24 inch centers with double top plate and single bottom plate. Corners use two studs or other means of fully insulating corners, and one stud is used to support each header. Headers consist of double 2x material with R-10 insulation between the header and exterior sheathing. Interior partition wall/exterior wall intersections are fully insulated in the exterior wall.[2]
Agrifiber Board – A composite panel product derived from recovered agricultural waste fiber from sources including, but not limited to, cereal straw, sugarcane bagasse, sunflower husk, walnut shells, coconut husks, and agricultural prunings. The raw fibers are processed and mixed with resins to produce panel products with characteristics similar to those derived from wood fiber. [4]
Alternative Fuel Vehicles – Vehicles that use low-polluting, non-gasoline fuels such as electricity, hydrogen, propane or compressed natural gas, liquid natural gas, methanol, and ethanol. Efficient gas-electric hybrid vehicles are included in this group for LEED purposes. [4]
Architectural Coatings – Coverings such as paint and roof tar that are used on exteriors of buildings. [1]

Backyard Composting – Diversion of organic food waste and yard trimmings from the municipal waste stream by composting hem in one’s yard through controlled decomposition of organic matter by bacteria and fungi into a humus-like product. It is considered source reduction, not recycling, because the composted materials never enter the municipal waste stream. [1]
Bioswale – A technology that uses plants and soil and/or compost to retain and cleanse runoff from a site, roadway, or other source. [4]
Blackwater – Does not have a single definition that is accepted nationwide. Wastewater from toilets and urinals is, however, always considered blackwater. Wastewater from kitchen sinks (perhaps differentiated by the use of a garbage disposal), showers, or bathtubs may be considered blackwater by state or local codes. Project teams should comply with the blackwater definition as established by the authority having jurisdiction in their areas. [4]
Blown-in-Blanket-System (BIBS) or blown-in batt – an insulation system that blows dry white fiberglass insulation into walls, floors, attics and cathedral ceilings held in place with a fabric containment screen. The system offers a more uniform R-Value throughout the entire cavity and controls air infiltration better than standard batt installations.
Building Envelope – Elements of the building, including all external building materials, windows, and walls, that enclose the internal space. [1]
Built Green – An environmentally-friendly, non-profit, residential building program of the Master Builders Association of King and Snohomish Counties, developed in partnership with King County, Snohomish County, and other agencies in Washington State.

CSBA – Certified Sustainable Building Advisor
Certified Lumber – General shorthand term for lumber that has been certified sustainable harvest by an independent certification authority. See Forest Stewardship Council. [4]
Chain of Custody – A document that tracks the movement of a wood product from the forest to a vendor and is used to verify compliance with FSC guidelines. A “vendor” is defined as the company that supplies wood products to project contractors or subcontractors for on-site installation. [4]
Cistern – Small tank or storage facility used to store water for a home or farm; often used to store rainwater. [4]
Commissioning – Start-up of a building that includes testing and adjusting HVAC, electrical, plumbing, and other systems to assure proper functioning and adherence to design criteria. Commissioning also includes the instruction of building representatives in the use of the building systems. [1]
Compact Fluorescent Lamp (CFL) – Small fluorescent lamps used as more efficient alternatives to incandescent lighting. Also called PL, CFL, Twin-Tube, or BIAX lamps. [4]
Composting Toilet Systems – Dry plumbing fixtures that contain and treat human waste via microbiological processes. [4]
Construction IAQ Management Plan – A document specific to a building project that outlines measures to minimize contamination in the building during construction, and to flush the building of contaminants prior to occupancy. [4]
Cubic feet per minute (CFM) – The amount of air, in cubic feet, that flows through a given space in one minute. 1 CFM equals approximately 2 liters per second (l/s). [1]

Daylight Sensing Control (DS) – A device that automatically regulates the power input to electric lighting near the glazing to maintain the desired workplace illumination, thus taking advantage of direct or indirect sunlight. [2]
Daylighting – The controlled admission of natural light into a space through glazing with the intent of reducing or eliminating electric lighting. By utilizing solar light, daylighting creates a stimulating and productive environment for building occupants. [4]
Degree-Day – A rough measure used to estimate the amount of heating required in a given area; is defined as the difference between the mean daily temperature and 65 degrees Fahrenheit. Degree-days are also calculated to estimate cooling requirements. [4]
Demand Hot Water System – Hot water heaters designed to provide instantaneous hot water, rather than storing preheated hot water in a tank. Such devices can serve an entire home, or be “point-of-use”, serving an individual water use. Benefits include elimination of “standby losses”, or energy wasted keeping stored water warm, and with point of use devices, reduction or elimination of water wasted waiting for water to get warm, as well as conductive losses as water travels through pipes. Electric demand systems tend to use a large amount of energy; gas-fired units with standing pilot lights lose much of their efficiency due to the ongoing pilot light. [4]
Drought Tolerance – The capacity of a landscape plant to function well in drought conditions. [4]
Durability – A factor that affects the life cycle performance of a material or assembly. All other factors being equal, the more durable item is environmentally preferable, as it means less frequent replacement. However, durability is rendered moot as a factor if the material is replaced for aesthetic reasons prior to it actually wearing out. [4]

Earth Air Heat Exchangers (EAHE) – relatively long conduits placed in the soil through which air passes and transfer heat either to or from the surrounding ground. These are utilized for either partial or full cooling and/or heating of facility ventilation air. [3]
Energy Analysis – Analysis of the energy use of a structure. [4]
Energy Modeling – Process to determine the energy use of a building based on software analysis. Also called building energy simulation. Common simulation software are DOE-2 and Energy Plus. [4]
Energy Recovery Ventilation (ERV) – the process of exchanging the energy contained in normally exhausted building or space air and using it to treat the incoming outdoor ventilation air in residential and commercial HVAC systems. The benefit of using energy recovery is the ability to meet the ASHRAE ventilation & energy standards, while improving indoor air quality, and reducing total HVAC equipment capacity. [3]
Energy Star – A U.S. government-backed program that helps businesses and individuals protect the environment through superior energy efficiency in buildings and appliances.
Engineered Lumber/Wood – Composite wood products made from lumber, fiber or veneer, and glue. Engineered wood products can be environmentally preferable to dimensional lumber, as they allow the use of waste wood and small diameter trees to produce structural building materials. Engineered wood products distribute the natural imperfections in wood fiber over the product, making them stronger than dimensional lumber. This allows for less material to be used in each piece, another environmental benefit. Potential environmental drawbacks with engineered wood include impacts on indoor environmental quality due to offgassing of chemicals present in binders and glues, and air and water pollution related to production. [4]

Fly Ash – Non-combustible residual particles expelled by flue gas. [1] A fine, glass-powder recovered from the gases of burning coal during the production of electricity. These micron-sized earth elements consist primarily of silica, alumina and iron. When mixed with lime and water the fly ash forms a cementitious compound with properties very similar to that of portland cement. Because of this similarity, fly ash can be used to replace a portion of cement in the concrete, providing some distinct quality advantages. The concrete is denser resulting in a tighter, smoother surface with less bleeding. Fly ash concrete offers a distinct architectural benefit with improved textural consistency and sharper detail. [4]
Formaldehyde – A colorless, pungent, and irritating gas, CH20, used chiefly as a disinfectant and preservative and in synthesizing other compounds like resins. [1]

Geothermal/Ground Source Heat Pump – These heat pumps are underground coils to transfer heat from the ground to the inside of a building. This type of heat pump can realize substantial energy savings over conventional heat pumps, by using the naturally more stable temperature of the earth as its heat source. [4]
Green Design – A design, usually architectural, conforming to environmentally sound principles of building, material and energy use. A green building, for example, might make use of solar panels, skylights and recycled building materials. [4]
Green Development – A sustainable approach to real estate development that incorporates such environmental issues as: efficient and appropriate use of land, energy, water, and other resources; protection of significant habitats, endangered species, archeological treasures and cultural resources; and integration of work, habitat and agriculture. Green development supports human and natural communities and cultural development while remaining economically viable for owners and tenants. [4]
Green Label – A certification program by the Carpet and Rug Institute for carpet and adhesives meeting specified criteria for release of volatile compounds. [4]
Green Roof – Contained green space on, or integrated with, a building roof. Green roofs maintain living plants in a growing medium on top of a membrane and drainage system. Green roofs are considered a sustainable building strategy in that they have the capacity to reduce stormwater runoff from a site, they modulate temperatures in and around the building, have thermal insulating properties, can provide habitat for wildlife and open space for humans, and other benefits. [4]
Greenwash – Disinformation disseminated by an organization so as to present an environmentally responsible public image. [4]
Ground-Coupled Heat Exchanger – (also known as Earth Tubes, earth cooling tubes or earth warming tubes) use the earth’s near constant subterranean temperature to warm or cool air for residential, agricultural or industrial uses. They are often a viable and economical alternative to conventional heating, cooling or heat pump systems since there are no compressors, chemicals or burners and only blowers are required to move the air. [3]

Heat Recovery Unit/Ventilator – An air-to-air heat exchanger with balanced exhaust and supply fans that meet all necessary ventilation needs without producing drafts or air pressure imbalance on a heating or cooling system. [4]
Heat Island Effect – A “dome” of elevated temperatures over an urban area caused by structural and pavement heat fluxes, and pollutant emissions. [1]
High Efficiency: General term for technologies and processes that require less energy, water, or other inputs to operate. A goal in sustainable building is to achieve high efficiency in resource use when compared to conventional practice. Setting specific targets in efficiency for systems (e.g., using only EPA Energy Star certified equipment, furnaces with an AFUE rating above 90%, etc.) and designs (e.g., watts per square foot targets for lighting) help put this general goal of efficiency into practice. [4]
HEPA – High efficiency particulate arrestance (filters). [1]
High-Heeled Truss – Roof truss design that allows space for insulation near the eaves. Conventional truss design limits the amount of insulation that can be applied in this area. [4]
Humidistat – A regulatory device, actuated by changes in humidity, used for automatic control of relative humidity. [2]

Impervious Surface – A surface that sheds the precipitation falling on it, rather than infiltrating. Impervious surfaces can lead to excessive stormwater runoff and limit the amount of stormwater that remains onsite or recharges local aquifers. [4]
Infiltration – The uncontrolled inward air leakage through cracks and interstices in any building element and around windows and doors of a building caused by the pressure effects of wind and/or the effect of differences in the indoor and outdoor air density. [2]
IAQ – Indoor air quality.
Insulated Concrete Form (ICF) – Expanded polystyrene forms that are left in place after the concrete is poured for a foundation or wall. The foam increases the thermal performance of the structure over non-insulated concrete. [4]
Insulation Baffle – A rigid material, resistant to wind driven moisture, the purpose of which is to allow air to flow freely into the attic or crawl space and to prevent insulation from blocking the ventilation of these spaces, or the loss of insulation. Example materials for this purpose are sheet metal or wax impregnated cardboard. [2]

LEED – Leadership in Energy and Environmental Design Green Building Rating System is the nationally accepted benchmark for the design, construction and operation of high performance, environmentally sustainable projects. LEED gives building owners and operators the tools they need to have an immediate and measurable impact on their buildings’ performance. LEED promotes a whole-building approach to sustainability by recognizing performance in five key areas of human and environmental health; sustainable site development, water savings, energy efficiency, materials selection and indoor environmental quality.
LEED AP – LEED Accredited Professional indicates an individual that has demonstrated a thorough understanding of green building practices and principles and the LEED Rating System. LEED Professional Accreditation distinguishes building professionals with the knowledge and skills to successfully steward the LEED certification process.
Linoleum – A resilient flooring product developed in the 1800s, manufactured from cork flour, linseed oil, oak dust, and jute. Linoleum’s durability, renewable inputs, anti-static properties, and easy-to-clean surface often make it classified as a “green” building material. [4]
Light Shelf – A horizontal shelf positioned (usually above eye level) to reflect daylight onto the ceiling and to shield direct flare from the sky. [5]
Local/Regional Materials – Building products manufactured and/or extracted within a defined radius of the building site. For example, the US Green Building Council defines local materials as those that are manufactured, processed and/or extracted within a 500-mile radius of the site. Use of regional materials is considered a sustainable building strategy due to the fact that these materials require less transport, reducing transportation-related environmental impacts. Additionally, regional materials support local economies, supporting the community goal of sustainable building. [4]
Low Emissivity (low-E) Windows – New window technology that lowers the amount of energy loss through windows by inhibiting the transmission of radiant heat while still allowing sufficient light to pass through. [1]
Low VOC – Building materials and finishes that exhibit low levels of “offgassing,” the process by which VOCs (Volatile Organic Compounds) are released from the material, impacting health and comfort indoors and producing smog outdoors. Low (or zero) VOC is an attribute to look for in an environmentally preferable building material or finish. See “Volatile Organic Compound (VOC)” for more information. [4]

Material Safety Data Sheet (MSDS) – A compilation of information required under the OSHA Communication Standard on the identity of hazardous chemicals, health, and physical hazards, exposure limits, and precautions. Section 311 of SARA requires facilities to submit MSDSs under certain circumstances. [1]
Modular Building – Building technique using modular, or pre-constructed components. Building on a “module” also refers to the concept of using standardized dimensions that reduce the amount of construction waste. Building in four-foot increments is one strategy. [4]

NaSBAP – The National Sustainable Building Advisor Program started in 1999 as a joint program offered by Seattle City Light and Seattle Central Community College to holistically educate working professionals about sustainable design and building. It is also recognized by the US Green Building Council (USGBC) as an approved Education Provider. Professional accreditation as a Certified Sustainable Building Advisor is earned with completion of the course and exam.
Night Flushing – The process of removing hot air from a building during the cool evening hours, to cool elements with thermal mass within the building and flush stale air. [4]
Non-potable – Water that is unsafe or unpalatable to drink because it contains pollutants, contaminants, minerals, or infective agents. [1]

Occupancy Sensor – A device that detects occupants within an area, causing any combination of lighting, equipment or appliances to be turned on or shut off. [2]
Off-gassing – Release of volatile chemicals from a product or assembly. Many chemicals released from materials impact indoor air quality and occupant health and comfort. Offgassing can be reduced by specifying materials that are low- or no-VOC and by avoiding certain chemicals (e.g., urea formaldehyde) entirely. Controlling indoor moisture, and specifying pre-finished materials, can also reduce offgas potential. [4]
Operations Manual (O&M Manual) – Manual developed to assist building occupants in maintaining and operating a green building and its features. Many features’ effectiveness can be reduced or eliminated by the actions (or inaction) of occupants and maintenance crews. An operations manual usually includes product and system information and warranties, contact information, and other information required for effective operations and maintenance. [4]
Oriented Strand Board (OSB) – A high strength, structural wood panel formed by binding wood strands with resin in opposing orientations. OSB is environmentally beneficial in that it uses small dimension and waste wood for its fiber; however, resin type should be considered for human health impact, and the production process monitored for air pollutant emissions. [4]
Overhangs – Architectural elements on roofs and above windows that function to protect the structure from the elements or to assist in daylighting and control of unwanted solar gain. Sizing of overhangs should consider their purpose, especially related to solar control. [4]

Passive Solar – Strategies for using the sun’s energy to heat (or cool) a space, mass, or liquid. Passive solar strategies use no pumps or controls to function. A window, oriented for solar gain and coupled with massing for thermal storage (e.g., a Trombe wall) is an example of a passive solar technique. [4]
Photocell – A device that measures the amount of incident light present in a space. [5]
Photovoltaics (PV) – the field of technology and research related to the application of solar cells for energy by converting solar energy (sunlight, including ultra violet radiation) directly into electricity. Installations may be ground-mounted or built into the roof or walls of a building, known as Building Integrated Photovoltaics or BIPV for short. [3]
Polyethylene Terepthalate (PETE or PET) – Thermoplastic material used in plastic soft drink and rigid containers. [1] Can b used in the production of recycled content carpet.

R-value – Quantitative measure of resistance to heat flow or conductivity, the reciprocal of U-factor. The units for R-value are ft2 ̊F hr/Btu (English) or m2 ̊K hr/W (SI or metric). While many in the building community consider R-value to be the primary or paramount indicator of energy efficiency, it only deals conduction, one of three modes of heat flow, (the other two being convection and radiation). As an example of the context in to which R-value should be placed, 25% to 40% of a typical home’s energy use can be attributed to air infiltration. [7]
Radiant Slab Floor – A slab floor assembly on grade or below, containing heated pipes, ducts, or electric heating cables that constitute a floor or portion thereof for complete or partial heating of the structure. [2]
Rain garden – a planted depression that allows rainwater runoff from impervious urban areas like roofs, driveways, walkways, and compacted lawn areas the opportunity to be absorbed. [3]
Rainscreen – a building enclosure rain control strategy that accepts that some water will penetrate the outer surface (the cladding, which “screens” rain) and removes this water back to the exterior by gravity drainage over a drainage plane, through a drainage gap, and exiting via flashing and weep holes. In essence it is a drained system, however, some use the term only for systems that have larger drainage gaps (e.g., 1/2″) or just for systems that are also ventilated (a ventilated drained approach) or just for systems that attempt to pressure-equalize. [7]

Sick Building Syndrome (SBS) – Term that refers to a set of symptoms that affect some number of building occupants during the time they spend in the building and diminish or go away during periods when they leave the building. Cannot be traced to specific pollutants or sources within the building. [1]
Solar thermal energy (STE) – a technology for harnessing solar energy for thermal energy (heat). Solar thermal collectors are defined by the USA Energy Information Administration as low-, medium-, or high-temperature collectors. Low temperature collectors are flat plates generally used to heat swimming pools. Medium-temperature collectors are also usually flat plates but are used for creating hot water for residential and commercial use. High temperature collectors concentrate sunlight using mirrors or lenses and are generally used for electric power production. STE is different from photovoltaics, which convert solar energy directly into electricity. [3]
Structural Insulated Panels (SIPS) – high performance building panels used in floors, walls, and roofs for residential and light commercial buildings. The panels are typically made by sandwiching a core of rigid foam plastic insulation between two structural skins of oriented strand board (OSB).
Sustainable Forestry – the practice of managing forest resources to meet the long-term forest product needs of humans while maintaining the biodiversity of forested landscapes. The primary goal is to restore, enhance and sustain a full range of forest values—economic, social and ecological. [6]

Thermal By-Pass – An area where the envelope surrounding the conditioned space is breached, or where an ineffective application compromises the performance of a thermal or infiltration barrier, increasing the structure’s energy consumption by exposing finished surfaces to ambient conditions and additional heat transfer. [2]
Thermal mass (also called heat capacity) – is the capacity of a mateial to store heat. Thermal mass provides ‘inertia’ against temperature fluctuations. When outside temperatures are fluctuating throughout the day, a large thermal mass within the insulated portion of the house can serve to ‘flatten out’ the daily temperature fluctuations, since the thermal mass will absorb heat when the surroundings are hotter than the mass, and give heat back when the surroundings are cooler. Thermal mass is effective in improving building comfort in any place that experiences daily temperature fluctuations—both in winter as well as in summer. When used well and combined with passive solar design, thermal mass can play an important role in major reductions to energy use in active heating and cooling systems. Thermal mass is ideally placed within the building and situated where it still can be exposed to winter sunlight (via windows) but insulated from heat loss. [3]
Trombe Wall – a sun-facing wall built from material that can act as a thermal mass (such as stone, metal, concrete, adobe or water tanks), combined with an air space, insulated glazing and vents to form a large solar thermal collector. [3]

USGBC – US Green Building Council
Urea-Formaldehyde Foam Insulation – A material once used to conserve energy by sealing crawl spaces, attics, etc.; no longer used because emissions were found to be a health hazard. [1]

Vapor Retarder – A layer of low moisture transmissivity material (not more than 1.0 perm dry cup) placed over the warm side (in winter) of insulation, over the exterior of below grade walls, and under floors as ground cover to limit the transport of water and water vapor through exterior walls, ceilings and floors. Vapor retarding paint, listed for this application, also meets this definition. [2]
Volatile Organic Compounds (VOCs) – Compounds that vaporize (become a gas) at room temperature. Common sources which may emit VOCs into indoor air include housekeeping and maintenance products, and building and furnishing materials. In sufficient quantities, VOCs can cause eye, nose, and throat irritations, headaches, dizziness, visual disorders, memory impairment; some are known to cause cancer in animals; some are suspected of causing, or are known to cause, cancer in humans. At present, not much is known about what health effects occur at the levels of VOCs typically found in public and commercial buildings. [1]

Weatherization – The process of reducing the leaks of heat from or into a building. It may involve caulking, weatherstripping, adding insulation, and other similar improvements to the building shell. [4]

Xeriscaping and Xerogardening – refers to landscaping and gardening in ways that reduce or eliminate the need for supplemental irrigation. [3]

Zeo-energy building – a building that produces at least as much energy as it consumes.


1. US Environmental Protection Agency.,
2. Washington State Energy Code.
3. Wikipedia.
4. City of Seattle DPD.…
5. Lighting Design Lab.
6. USGBC LEED NC 2.2 Reference Guide
7. Building Science.