Glossary of Green Terms

We know the whole Green Home concept can at times be confusing.  Terms like “Carbon Footprint”, “BPA”, “LEED“, and “FSC” are all new and it can be hard to keep up.  Below, are some of the common terms used both on our site and in broader discussions about sustainability.  Always refer back to this glossary page if you have questions.  You can even bookmark this green glossary for easy access.

Don’t see the term here that you care about?  E-mail our Director of Sustainability at and we’ll get it added to our glossary of green terms.

acrylic: a synthetic textile, resin, or paint derived from acrylic acid.

aldehydes: a group of highly reactive chemical compounds used in making resins and dyes. Volatile organic compounds (VOCs). One of the better-known members of this group is formaldehyde.

biodegradable: capable of being decomposed by the action of living organisms.

biodiversity: the degree of variation of  lifeforms within a given ecosystem, biome, or entire planet. Biodiversity is a measure of the health of an ecosystem.

bisphenol-a (BPA): an industrial chemical best known for making polycarbonate plastic and epoxy resins. Found in hard plastic water bottles and baby bottles, in coatings inside metal food and drink cans, and in paints, adhesives, dental sealants, computers, and other products. BPA is an estrogen-mimicking chemical that, in tests on animals, has been shown to interfere with the reproductive system.

British thermal unit (Btu): the amount of heat required to raise the temperature of 1 pound of liquid 1 ºF. A single gallon of propane contains 91,600 Btu. A cord of wood contains 12 million to 33 million Btu, depending on the type of wood.

brominated flame retardants: chemicals added to plastics, textiles, furniture foam and padding, and other products to prevent them from catching fire. BFRs, as they are also known, are long-lived poisons that build up in fat. In animal studies, they have been linked to hormonal and neurological disorders.

buckwheat: a plant cultivated for its triangular grains, which are protected by a hull. This crop is generally grown without herbicides and pesticides.

building paper: also called building felt or housewrap; used in the construction of frame houses to block drafts and moisture. Building paper is applied in layers over a house’s walls and sheathing, with the top courses overlapping the bottom courses so that water drains off the wall.

carbon footprint: the impact a particular activity has on the environment in terms of the amount of climate-changing carbon dioxide and other greenhouse gases it produces. A person’s carbon footprint is the amount of greenhouse gases that his or her way of life produces overall.

caulk: filling or sealing compound used to make a home or building material more airtight or watertight.

cellulose: the structural component of the primary cell wall of green plants.

carbon dioxide (CO2 ): a colorless, odorless gas formed by respiration, decomposition of organic matter and combustion. CO2 is a greenhouse gas that traps heat in the atmosphere. Since the 1700s, deforestation and the burning of fossil fuels have boosted the amount of atmospheric CO2 by 35%, increasing temperatures worldwide.

carbon offseta reduction in emissions of carbon dioxide or greenhouse gases made in order to compensate for or to offset an emission made elsewhere.

clean-tech: a diverse range of products that harness renewable materials and energy sources, dramatically reduce the use of natural resources, and cut or eliminate emissions and waste. The three main clean technology sectors are solar photovoltaics, wind power, and biofuels, and Silicon Valley is considered the base of clean-tech in the U.S.

composite wood: also called “engineered wood”; made of strands, particles, fibers, or veneers of wood bound with adhesives. Products include particle board, plywood, and medium-density fiberboard (MDF).

condenser coils: in a refrigerator or air conditioner, the tubes that carry refrigerant, which must be kept clean to work properly. On most refrigerators, condenser coils are accessible by removing the kick plate on the bottom. “No-clean” models have coils mounted on the back.

cord: a unit of wood that has been cut for burning; 128 square feet, or a stack 4′ x 4′ x 8′.

cotton: a soft, fluffy plant fiber that can be bad or good environmentally, depending upon which type you buy: 1) conventional cotton has been sprayed with pesticides and may have been processed with toxic chemicals or have toxic finishes; 2) green cotton has been sprayed with pesticides, but is not processed or finished with any chemicals; 3) organic cotton is grown without pesticides and from plants that are not genetically modified. A “100% organic” label backed by the Organic Trade Association or the Global Organic Textile Standard gives you the additional assurance that it was not processed or finished with any toxic chemicals.

dioxins: long-lasting highly toxic hydrocarbons; byproducts of various industrial processes, including paper and pesticide manufacturing and waste incineration. Dioxins are the most potent carcinogens known to science and also may affect human development and reproduction.

double-hung windows: a traditional window style with two glass-holding frames that slide past each other vertically.

down: birds’ soft, fluffy inner feathers. Goose down is softer and more long-lasting than duck down, but it’s also more expensive. Eiderdown, from the eider duck, is the softest, lightest, warmest, and most expensive down in the world.

dry rot: a crumbling and drying of wood that is caused by a fungus; turns wood into powder.

Energy Star: a U.S. government program run by the EPA and the Department of Energy that promotes energy efficiency. The program measures how much energy it takes to run various appliances and other products, and gives an Energy Star label to those in the top tier of energy efficiency. The program estimates that a typical U.S. household, which spends about $2,000 on energy each year, could save $700 annually by purchasing products with Energy Star labels.

EPA: the U.S. Environmental Protection Agency.

engineered wood: a broad category of structural and nonstructural building materials made from wood bound with adhesives. Includes framing studs, beams, and roof and floor joists, as well as composite wood such as particle board, plywood, and medium-density fiberboard.

epoxy: a tough resin that cures when mixed with a hardener. Most epoxy resins are produced from a reaction between from a reaction between epichlorohydrin and the estrogen-mimicking chemical BPA. used in adhesives, coatings, and laminates. Gives off toxic fumes as it dries.

EV: electric vehicles; cars that run on electric-powered batteries.

flame retardants: materials that inhibit the ignition and spread of fire. Flame retardants can be minerals, synthetic chemicals, or other materials. Chemical flame retardants are used in carpets, mattresses, clothing, furniture, furniture padding, plastics, and other products.

flashing: a thin layer of impermeable material (often sheet metal) used in construction to prevent water penetration and provide drainage. Often used between a roof and a wall or over exterior door and window openings.

formaldehyde: a noxious gas used to manufacture many building materials and household products, including adhesives in engineered wood and in the processing of wrinkle-resistant fabrics. It can cause allergic reactions and irritate respiratory systems and has been classified as a “known carcinogen” by the World Health Organization.

Forest Stewardship Council (FSC): a nonprofit organization whose mission is “to promote environmentally appropriate, socially beneficial, and economically viable management of the world’s forests.” The Council develops forest management standards and works with certification organizations that inspect and certify forestry operations. Lumber and other wood products from FSC-certified operations are supposed to be grown and logged in accordance with FSC’s principles, and carry the FSC ecolabel. 

global warming gases: also called “greenhouse gases”(GHGs); include carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons. In the atmosphere, these gases all trap solar radiation and raise temperatures on the Earth’s surface-a phenomenon called “the greenhouse effect.”

greenhouse gases (GHGs): include carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons. In the atmosphere, these gases all trap solar radiation and raise temperatures on the Earth’s surface-a phenomenon called “the greenhouse effect.”

Green Seal: an independent nonprofit that sets voluntary environmental and health standards for products and helps consumers learn about products that meet those standards.

GreenCheck®: A program offered by Sierra Club Green Home to help site users (i.e., consumers) find providers who maintain that they are green businesses. The GreenCheck® indicates that the business asserts a legitimate and meaningful effort to offer a product or service that is more sustainable than what is commonly sold. Though the GreenCheck® vetting process asks about green credentials, it is not a certification or accreditation process. SCGH relies on users to review businesses and tell SCGH if any do not merit continued inclusion in the Green Directory on

hardboard: a type of composite-wood construction material made from wood chips compressed into sheets and bound with a synthetic resin.

heat-island effect: the tendency of urban and suburban areas to be warmer than adjacent rural areas. In the United States, such built environments are 2 to 10°F warmer-a function of less vegetation, reduced airflow, and large areas of roofs, asphalt, concrete, and paved surfaces that absorb the sun’s heat.

hemp: a durable plant fiber that is generally grown and processed without pesticides or synthetic chemicals.

HVAC: Heating, ventilating, and air conditioning

hydrogen fuel cell: a device that makes hydrogen and oxygen into water, creating electricity in the process. An electrochemical energy conversion device.

lauan: a wood from any of some 70 species of Southeast Asian trees in the genus Shorea; also know as Philippine mahogany. Its color can be yellowish, gray, brown, or red.

latex, natural: the milky sap produced by the rubber tree, a tropical species; a renewable product-when sap is taken from the tree it responds by producing more.

lead: a toxic metal that can harm virtually every system in the body, and is particularly dangerous to the developing brain and nervous systems of young children. Children under the age of six are the most vulnerable.

LEDs: light-emitting diodes; semiconductors that produce light when electricity passes through them. LEDs are considerably more energy efficient than incandescent lights.

LEED: Leadership in Energy and Environmental Design-a program of the U.S. Green Building Council, which sets standards for environmentally sustainable construction and certifies buildings that meet these standards.

MDF (medium density fiberboard): a type of engineered wood similar to particle board but stronger, denser and more moisture resistant; typically used for cabinets, furniture, and moldings.

modal: A sturdy, absorbent fabric made from beechwood chips; feels silky.

mold: fungi that reproduce by spores and can break down organic matter. Common in moist areas. Can cause health problems and allergic reactions. Some 40% of U.S. households have a problem with mold in their homes.

MSDS (material data safety sheet): provides information for workers and safety personnel about potentially hazardous substances. Includes such information as melting point, boiling point, toxicity, reactivity, and health effects. In the United States, the Occupational Safety and Health Administration requires that an MSDS be available for potentially harmful substances in the workplace.

old-growth forests: also called “ancient” or “virgin” forests; an expanse of native trees that have not been logged for hundreds of years. Contains multiple vertical layers of vegetation with a wide variety of species and ages, as well as excellent habitat for some rare wildlife species.

oriented strand board (OSB): a type of engineered wood consisting of strips of wood arranged in crisscrossing layers bound with an adhesive and made into panels. Often used as subflooring or wall or roof sheathing.

ozone layer, ozone-depleting substances: Located in the stratosphere, “the ozone layer” is composed of molecules of ozone (O3) that shield the Earth from ultraviolet radiation. Chlorofluorocarbons, once widely used as aerosol propellants and refrigerants, are one of several “ozone-depleting substances” that have thinned the ozone layer near the Earth’s poles.

passive solar heating: a building design strategy that takes maximum advantage of the sun’s natural ability to provide warmth, with features that include south-facing windows, well-insulated walls and ceilings, and thermal storage in materials such as concrete, ceramic tile, rock, and water.

PCBs: Since they were first introduced to U.S. industries in 1929, polychlorinated biphenyls were widely used as coolants and lubricants in electrical equipment. It was later found that these chlorinated organic compounds could harm the brain, nervous, and hormone systems. The United States banned manufacture of PCBs in 1977, but they remain in the environment and in the food chain. Some environmental experts believe that at least 75% of PCBs are yet to be released to the environment. People are sometimes adding PCBs to their system when they eat fatty foods.

PBDE: Polybrominated diphenyl ethers, a class of flame-retardant chemicals that have shown up in human breast milk and in the fatty tissues of arctic mammals. According to the EPA, there is evidence that PBDEs may cause “liver toxicity, thyroid toxicity, and neurodevelopment toxicity.” Exactly how PBDEs are getting into our bodies isn’t yet known, but scientists suspect that as PBDE-treated products age, the chemical may break down and adhere to household dust.

PEVA (polyethylene vinyl acetate): a chlorine-free substitute for plastics made of PVC (polyvinyl chloride, often simply called “vinyl”) that is considered less harmful.

perfluorocarbons, perfluorochemicals (PFCs): These “fluorinated” chemicals repel both oil and water, and so are widely used in water, stain, and grease repellants for food wrap, carpet, furniture, and clothing. They don’t break down easily, however, and have been detected in the bodies of adults, newborns, and wildlife all around the world. Research on their effects is in its infancy. “The present state of knowledge on perfluorocarbons might be compared to the situation with PCBs in the 1960s,” says a June 2004 article on the Environmental Working Group website, “when their environmental persistence-and its consequences-was just beginning to be realized.” Fluorine belongs to the halogen family of elements along with chlorine and bromine, and is similarly fraught with health issues.

perfluorooctanic acid (PFOA): a fluorinated chemical thought to be a carcinogen that is turning up in the bloodstream of humans and animals. PFOA and related perfluorochemicals have been used for decades to make a variety of nonstick and water-repellant products, including Teflon and other nonstick cookware, stain treatments for carpets, waterproof clothing, greaseproof liners of food packaging, and some personal care products. In 2006, manufacturers reached a voluntary agreement with the U.S. EPA to eliminate almost all use of PFOA by 2015, although the use of other fluorinated chemicals[link to perfluorocarbons] will continue.

photovoltaic (PV):  is a method of generating electrical power by converting solar radiation into direct current electricity. PVC refers to photovoltaic cells in solar panels or modules.

phthalates: used in vinyl products to make them softer and more flexible; also in cosmetics, fragrances, food wraps, and other products. In baby boys, exposure to phthalates can likely increase the risk of birth defects and hormone changes. In men, they likely increase the risk of reproductive problems and hormone changes. The U.S. government regulates industrial discharges of phthalates, but they are unregulated in food products, cosmetics, and consumer and medical products.

picoCurie, pCi: one trillionth of a curie, a unit of radioactivity.

ppm: parts per million

polycarbonate plastic: a hard plastic used to make water bottles, baby bottles, and other products. This plastic contains the chemical bisphenol-a (BPA), an estrogen-mimicking chemical that, in tests on animals, has been shown to interfere with the reproductive system. Some BPA leaches into water at room temperature. Researchers at the University of Cincinnati College of Medicine report that putting boiling water in a polycarbonate container increased the migration rate by as much as 55 times. Other studies indicate that older containers leach BPA at a faster rate than newer containers. Thermo Fisher Scientific, the maker of the popular Nalgene brand of polycarbonate bottles, decided to stop using polycarbonate plastic in its bottles in 2008.

polyester: most often refers to a synthetic fabric made from polyethylene terephthalate (PET), the same material used to make single-use plastic drink bottles. Sometimes such bottles are recycled to make polyester fabric.

polyethylene (PE): widely used in packaging and other products. While less harmful than other plastics, it is still a degradative material to our health and ecosystem.

polyurethane: a resin that can be rigid or flexible, used in durable coatings, adhesives, and foams. When used as an adhesive in wood, it’s less toxic than urea formaldehyde.

polyvinyl chloride (PVC): also known as “vinyl.” A plastic widely used in construction materials, including siding, pipes and plumbing fixtures, insulation for wires and cables, and carpets, and in many other products. When made soft and flexible by the addition of plasticizers, vinyl is often used for shower curtains, raincoats, lunch box linings, and baby teethers. According to the Healthy Building Network, “PVC is the worst plastic from an environmental standpoint.” Its manufacturing process creates dioxins, the most potent carcinogen known to science. Its plasticizers are usually hormone-disrupting phthalates. And it releases more dioxin when it burns.

portland cement: a construction material made from limestone and clay that hardens under water. With sand and gravel added, it becomes “concrete.”

post-consumer waste: in the recycling business, material that has already been used and discarded by consumers, as opposed to manufacturing waste. Using products with “post-consumer” recycled content actually keeps waste out of landfills and incinerators, unlike “post-industrial” recycled content, most of which would get recycled anyway.

power washing: cleaning with a machine that delivers a high-pressure water spray.

pre-consumer waste: waste generated in the manufacturing process, as opposed to “post-consumer waste”-waste from products that consumers have used and discarded. Also called “post-industrial” waste.

quat: a copper-based wood preservative sanctioned by the EPA, used as a less-toxic alternative to chromated copper arsenate, which was banned for most residential uses in 2003.

radiant floor heating: a heating system that warms the floor, which radiates heat to the whole house.

radon: a radioactive gas produced by decaying uranium in soil; when it accumulates in homes, it can be hazardous to human health.

renewable materials: materials that can be replaced as fast as they are used up, such as sunlight or well-managed timber supplies.

silk: a strong, flexible filament from the cocoon of the silkworm. A natural material that is unlikely to cause an allergic response.

storm windows: a secondary window added to the outside of the regular window, usually in winter, to protect against wind and cold.

styrene: a synthetic chemical used in the manufacture of plastics, rubber, and resin; a volatile organic compound (VOC) that affects the central nervous system and is a potential carcinogen, according to the International Agency for Research on Cancer.

sustainable: using a resource in a way that neither depletes nor permanently damages it; capable of being sustained.

terrazzo: a mix of marble, other stone, or recycled glass in a matrix of concrete or epoxy. Used for countertops and floors.

toluene: a colorless flammable liquid made from petroleum or coal tar; used as a solvent for adhesives and lacquers; a volatile organic compound (VOC) that is a potential carcinogen.

upcycle: to convert discarded, used, or waste materials into something of a higher quality or value; hence “upcycling” instead of merely “recycling.”

watt: a unit of electric power or work.

vinyl: shorthand for polyvinyl chloride or PVC. A plastic widely used in construction materials, including siding, pipes and plumbing fixtures, insulation for wires and cables, and carpets, and in many other products. When made soft and flexible by the addition of plasticizers, vinyl is often used for shower curtains, raincoats, lunch box linings, and baby teethers. According to the Healthy Building Network, “PVC is the worst plastic from an environmental standpoint.” Its manufacturing process creates dioxins, the most potent carcinogen known to science. Its plasticizers are usually hormone-disrupting phthalates. And it releases more dioxin when it burns.

Volatile Organic Compounds (VOCs): a huge class of carbon-based chemicals that vaporize at room temperature, releasing gases into the air. They include formaldehyde, propane, butane, toluene, and acetone. Homes often contain hundreds of products that release minute quantities of these gases-paints, adhesives, carpet, plastics, cleaning products, and personal care products-but there are less toxic alternatives.

wet cleaning: a non-toxic, environmentally safe alternative to dry cleaning.

wool: the shorn coat of various animals. Wool fibers are curly and therefore naturally resilient; wool doesn’t mat down and won’t clump or shift. It’s also breathable, non-allergenic, and naturally resistant to mold, dust mites, and bacteria.


  1. J.Muller October 1, 2010
  2. chimney inspections November 28, 2011
  3. Lyda October 24, 2012
  4. keith January 9, 2013

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