A unit that equals 20 long hundredweight or 2,240 pounds. Used mainly in England.

A construction element used to cover the exterior of wall framing and roof trusses.

A national trade association of solar energy equipment manufacturers, retailers, suppliers, installers, and consultants.

A high R-value insulation product usually made from urethane that can be injected into wall cavities, or sprayed onto roofs or floors, where it expands and sets quickly.

A popular term for energy produced from renewable energy resources.

A measure of the unavailable or unusable energy in a system; energy that cannot be converted to another form.

A term used to describe solar thermal, central receiver, power systems, where an array of reflectors focus sunlight onto a central receiver and absorber mounted on a tower.

A power plant that uses two thermodynamic cycles to achieve higher overall system efficiency; e.g.: the heat from a gas-fired combustion turbine is used to generate steam for heating or to operate a steam turbine to generate additional electricity.

The quantity of heat that a cooling appliance is capable of removing from a room in one hour.

To price and sell greenpower/electricity higher than that produced from fossil or nuclear power plants, supposedly because some buyers are willing to pay a premium for greenpower.

Steam available directly from a boiler under full pressure.

A measure of light quality. The maximum CRI value of 100 is given to natural daylight and incandescent lighting. The closer a lamp's CRI rating is to 100, the better its ability to show true colors to the human eye.

The ratio of average energy demand (load) to maximum demand (peak load) during a specific period.

A type of insulation that is molded or expanded to produce coarse, closed cells containing air. The rigid cellular structure provides thermal and acoustical insulation, strength with low weight, and coverage with few heat loss paths. Often used to insulat ...

A method used to estimate building heating loads by assuming that heat loss and gain is proportional to the equivalent heat-loss coefficient for the building envelope.

The net south-facing glazing area projected on a vertical plane. Also, the solid area covered at any instant by a wind turbine's blades from the perspective of the direction of the windstream (as opposed to the swept area).

A measure of the quality of a light source by expressing the color appearance correlated with a black body.

Salt mixtures with potential applications as solar thermal energy storage materials.

Those gases, such as water vapor, carbon dioxide, tropospheric ozone, methane, and low level ozone that are transparent to solar radiation, but opaque to long wave radiation, and which contribute to the greenhouse effect.

A coating applied to the surface of the glazing of a window to reduce heat transfer through the window.