Ratio of useful energy output of a device to the energy input, averaged over an entire heating season.

A solar thermal collector that has an absorber that does not have a glazed covering. Solar swimming pool heater systems usually use unglazed collectors because they circulate relatively large volumes of water through the collector and capture nearly 80 pe ...

The housing around a motor that supports the active parts and protects them. They come in different varieties (open, protected) depending on the degree of protection required.

A type of heat pump that uses sealed horizontal or vertical pipes, buried in the ground, as heat exchangers through which a fluid is circulated to transfer heat.

A light source composed of a metal base, a glass tube filled with an inert gas or a vapor, and base pins to attach to a fixture.

Generation of energy at the location where all or most of it will be used.

To heat a gaseous mixture to the temperature at which combustion takes place.

Those elements of building used to control the interior climate.

A large number of thermocouples connected in series.

The unit of illuminance equivalent to 1lumen per square meter.

The pressure of the steam or water in a boiler as measured; usually expressed in pounds per square inch gauge (psig).

The unit of magnetic field intensity equal to 1 dyne per unit pole.

As defined in the Energy Security Act (P.L. 96-294; 1980) as "any organic matter, including sewage, sewage sludge, and industrial or commercial waste, and mixtures of such matter and inorganic refuse from any publicly or privately operated municipal waste ...

An architectural design (also known as the double envelope house), sometimes called a "house-within-a-house," that employs a double envelope with a continuous airspace of at least 6 to 12 inches on the north wall, south wall, roof, and floor, achieved by ...

The rate of heat production by a steady current in any part of an electrical circuit that is proportional to the resistance and to the square of the current, or, the internal energy of an ideal gas depends only on its temperature.

A charge for the maximum rate at which energy is used during peak hours of a billing period. That part of a utility service charged for on the basis of the possible demand as distinguished from the energy actually consumed.

A heat absorbing reaction or a reaction that requires heat.

The prescribed level of pollutants allowed in outside or indoor air as established by legislation.

A device that converts heat or sunlight directly to electricity, invented by Standford Ovshinsky, that has a unique glass composition that changes from an electrically non-conducting state to a semiconducting state.

A compound used to make certain types of solar photovoltaic cells.