A complete lighting unit consisting of a lamp(s), housing, and connection to the power circuit.

A type of combustion heating system in which combustion air is drawn directly from outside and the products of combustion are vented directly outside. These features are beneficial in tight, energy-efficient homes because they will not depressurize a home ...

The direct, diffuse, and reflected solar radiation that strikes a surface.

The process of converting municipal solid waste to energy and/or recovering materials for recycling.

A system in which a working fluid is used over and over without introduction of new fluid, as in a hydronic heating system or mechanical refrigeration system.

A slightly sloped roof, usually with a tar and gravel cover. Most commercial buildings use this kind of roof.

A high-efficiency photovoltaic device containing two or more cell junctions, each of which is optimized for a particular part of the solar spectrum.

A particle of light that acts as an individual unit of energy.

The temperature of the air as measured by a standard thermometer.

A term for the process of transmitting electricity over transmission lines not owned by the supplier of the electricity to a retail customer of the supplier. With retail wheeling, an electricity consumer can secure their own supply of electricity from a b ...

A self-contained toilet that use the process of aerobic decomposition (composting) to break down feces into humus and odorless gases.

The relative extent that energy is required for a process.

Air that provides the necessary oxygen for complete, clean combustion and maximum heating value.

A measure of the moisture content of air; may be expressed as absolute, mixing ratio, saturation deficit, relative, or specific.

Any wholly or partially enclosed space in which combustion takes place.

A heat exchanger in a solar water heating system that has two distinct walls between the heat transfer fluid and the domestic water, to ensure that there is no mixing of the two.

A cooling device that uses mechanical energy to produce chilled water.

An energy band in a semiconductor in which electrons can move freely in a solid, producing a net transport of charge.

Water heated for residential washing, bathing, etc.

The number of cycles through which an alternating current passes per second; in the U.S. the standard for electricity generation is 60 cycles per second (60 Hertz).