Freshly cut, unseasoned, wood.

The process by which sunlight directly enters a building through the windows and is absorbed and stored in massive floors or walls.

A unit of illuminance; equal to one lumen per square foot.

see Solar Spectrum above.

The amount of conditioned air to be supplied by a cooling system; usually the maximum amount to be delivered based on a specified number of cooling degree days or design temperature.

Pounds/force per square inch absolute.

In reference to a wind energy conversion system, the wind speed profile in which wind speeds increase with the logarithmic of the height of the wind turbine above the ground.

A device in which organic material is biochemically decomposed (digested) by anaerobic bacteria to treat the material and/or to produce biogas.

The value or purchasing power of a dollar in a specified year carried forward or backward.

A source of power (electricity) that can displace power from another source so that source's power can be transmitted to more distant loads.

The ratio of actual power being used in a circuit, expressed in watts or kilowatts, to the power that is apparently being drawn from a power source, expressed in volt-amperes or kilovolt-amperes.

Steam available directly from a boiler under full pressure.

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

The space between a hanging ceiling and the floor above or roof; usually contains HVAC ducts, electrical wiring, fire suppression system piping, etc.

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

A unit of volume equal to 1 cubic foot at a pressure base of 14.73 pounds standard per square inch absolute and a temperature base of 60 degrees Fahrenheit.

A type of furnace in which fuel is burned and the heat is used to produce steam.

A fuel gas with a heating value between 90 and 200 Btu per cubic foot.

A solar energy system designed to provide heat to individual rooms in a building.