Forces that lift water or pull it through porous materials, such as concrete. The tendency of a material to wick water due to the surface tension of the water molecules.

Amount of carbon dioxide and other greenhouse gases that a person, community, industry, or other entity contributes to the atmosphere through energy use, transportation, and other means.

Carbon credits purchased to offset the purchaser’s carbon dioxide emissions.

Surface, typically on a roof, where rainwater is caught and directed into a rainwater harvesting system.

An unvented attic with insulation installed between the rafters or above the roof sheathing. Moving the insulation from the attic floor to the roof plane turns the attic into conditioned or semi-conditioned space; this is especially beneficial in homes with attic ductwork. The term “cathedralized attic” usually refers to an attic that does not include finished space.

Wall assembly constructed of two wythes of masonry bonded with wall ties and separated by an air cavity, which is sometimes filled with insulation.

A safety test in which the potential for backdrafting of combustion appliances is assessed by turning on all exhaust fans in a home and then visual assessing appliance combustion exhaust performance or using pressure testing to assess the extent of depressurization in the location of the combustion appliance.

Thermal insulation made from recycled newspaper or other wastepaper; often treated with borates for fire and insect protection.

Compact fluorescent lamp. Fluorescent lightbulb in which the tube is folded or twisted into a spiral to concentrate the light output. CFLs are typically three to four times as efficient as incandescent lightbulbs, and last eight to ten times as long. CFLs combine the efficiency of fluorescent light with the convenience of an Edison or screw-in base, and new types have been developed that better mimic the light quality of incandescents. Not all CFLs can be dimmed, and frequent on-off cycling can shorten their life. Concerns have been raised over the mercury content of CFLs, and though they have been deemed safe, proper recycling and disposal is encouraged.

Meeting at the beginning of an integrative design process that sets the stage for cooperation and collaboration among all participants, including the design team, engineers, contractors, clients, and any others involved in the project. Early involvement of the entire project team is fundamental to the successful use of a systems approach to green building.

Materials used on the roof and walls to enclose a house, providing protection against weather.

Concrete masonry unit. Precast concrete block used to build walls. CMUs have hollow cores that can be filled with concrete onsite for additional reinforcement. The use of stronger, more lightweight types of concrete such as autoclaved aerated concrete (AAC) is becoming increasingly popular in CMU manufacture.

Energy-efficiency measurement of heating, cooling, and refrigeration appliances. COP is the ratio of useful energy output (heating or cooling) to the amount of energy put in, e.g., a heat pump with a COP of 10 puts out 10 times more energy than it uses. A higher COP indicates a more efficient device . COP is equal to the energy efficiency ratio (EER) divided by 3.415.

Development pattern in which multiple (typically 8 to 30) privately owned houses or housing units are clustered together with some commonly owned spaces, such as a common workshop, greenhouse, etc. Automobiles are typically kept to the perimeter of the community, creating a protected area within where children can play. Usually, residents are closely involved in all aspects of the development, from site selection to financing and design.

Process of testing a home after a construction or renovation project to ensure that all of the home's systems are operating correctly and at maximum efficiency.

Lumber, typically decking, made from plastic (often high-density polyethylene) and wood fiber or other agricultural by-products. Composite lumber often contains recycled content. Also called composite decking.

Insulated, air-sealed part of a building that is actively heated and/or cooled for occupant comfort.

Movement of heat through a material as kinetic energy is transferred from molecule to molecule; the handle of an iron skillet on the stove gets hot due to heat conduction. R-value is a measure of resistance to conductive heat flow.

Term used to describe the recycling of waste materials and manufactured products into new products rather than permanently disposing of them (see cradle to grave). The concept and its societal implications was the focus of the 2002 book Cradle to Cradle: Remaking the Way We Make Things by chemist Michael Braungart and architect William McDonough.