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

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

The mean distance a free electron or hole moves before recombining with another hole or electron.

A device that converts high-pressure steam, produced in a boiler, into mechanical energy that can then be used to produce electricity by forcing blades in a cylinder to rotate and turn a generator shaft.

A measure of the ability of a light source to show colors, based on a color rendering index.

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

A plot of a wind energy conversion device's power output versus wind speed.

The air that is supplied to the combustion chamber of a furnace.

A unit for the quantity of electricity transported in 1 second by a current of 1 ampere.

A glazed structure, such as greenhouse or "sunspace."

A heating system in which steam or hot water for space heating or hot water is piped from a central boiler plant or electric power/heating plant to a cluster of buildings.

Energy that is capable or available for doing work; the time rate at which work is performed, measured in horsepower, Watts, or Btu per hour. Electric power is the product of electric current and electromotive force.

The monochromatic irradiance of a surface per unit bandwidth at a particular wavelength, usually expressed in Watts per square meter-nanometer bandwidth.

A type of window glazing films used to block the infrared (heat) portion of the solar spectrum but admit a higher portion of visible light.

A type of automatic thermostat (used on solar heating systems) that responds to temperature differences (between collectors and the storage components) so as to regulate the functioning of appliances (to switch transfer fluid pumps on and off).

The practice of installing blow-in, loose-fill insulation at a lower density than is recommended to meet a specified R-Value.

Strips of material used to separate multiple panes of glass within the windows.

In reference to solar photovoltaic devices, a material that is composed of a single crystal or a few large crystals.

A concrete pad that sits on gravel or crushed rock, well-compacted soil either level with the ground or above the ground.

A type of water heater in which heated water is stored within the tank. Hot water is released from the top of the tank when a hot water faucet is turned. This water is replaced with cold water that flows into the tank and down to just above the bottom pla ...