A heat source, such as a space heater, used to provide more heat than that provided by a primary heating source.

The measure of closeness in shape between a waveform and it's fundamental component.

A small groove scribed into the surface of a solar photovoltaic cell which is filled with metal for contacts.

A popular term for highly insulating window with a heat loss so low it performs better than an insulated wall in winter, since the sunlight that it admits is greater than its heat loss over a 24 hour period.

The storage of compressed air in a container for use to operate a prime mover for electricity generation.

The physical material upon which a photovoltaic cell is applied.

The amount of energy an energy storage device or system can store.

The amount of fuel necessary to generate one kilowatt-hour of electricity.

A common utility monetary measure equal to one-thousandth of a dollar or a tenth of a cent.

The average amount of solar radiation that reaches the earth's upper atmosphere on a surface perpendicular to the sun's rays; equal to 1353 Watts per square meter or 492 Btu per square foot.

A measure of the probability that a system demand will exceed capacity during a given period; often expressed as the estimated number of days over a long period, frequently 10 years or the life of the system.

A smokestack or flue for exhausting the products of combustion from a combustion appliance.

ICS solar systems are also called "batch" or "breadbox" water heaters. They combine the collector and storage tank in one unit. The sun shining into the collector strikes the storage tank directly, heating the water. The large thermal mass of the water, p ...

A computer software program that simulates energy consumption of commercial buildings; used for design and auditing purposes.

A type of High-Intensity Discharge (HID) lamp that uses sodium under high pressure as the primary light-producing element. These high efficiency lights produce a golden white color and are used for interior industrial applications, such as in warehouses a ...

A unit of mass equal to 1,000 kilograms or 2,204.6 pounds.

As defined by the Comprehensive National Energy Act of 1992 (or the Energy Policy Act; EPAct): any organic matter from a plant which is planted for the exclusive purpose of being used to produce energy." This does not include wood or agricultural wastes o ...

The nominal voltage for which a conductor or electrical appliance is designed; the reference voltage for identification and not necessarily the precise voltage at which it operates.

The two times of the year when the sun crosses the equator and night and day are of equal length; usually occurs on March 21st (spring equinox) and September 23 (fall equinox).

Methyl Tertiary Butyl Ether (MTBE) is an ether compound used as a gasoline blending component to raise the oxygen content of gasoline. MTBE is made by combining isobutylene (from various refining and chemical processes) and methanol (usually made from nat ...