Any material that has a limited capacity for conducting an electric current. Certain semiconductors, including silicon, gallium arsenide, copper indium diselenide, and cadmium telluride, are uniquely suited to the photovoltaic conversion process.

A device that uses electronic components to regulate the voltage of fluorescent lamps.

A way of joining photovoltaic cells or modules by connecting positive leads together and negative leads together; such a configuration increases the current, but not the voltage.

A configuration of an electrical circuit in which the positive lead is connected to the negative lead of another energy producing, conducting, or consuming device. The voltages of each device are additive, whereas the current is not.

For valves and fittings, implies that they are suitable for working pressures between 125 to 175 pounds per square inch.

A heat exchanger in which heat is recovered from the products of combustion.

The rate of energy transfer equivalent to one ampere under an electrical pressure of one volt. One watt equals 1/746 horsepower, or one joule per second. It is the product of Voltage and Current (amperage).

The replacement of a non-functional or ineffective lamp with a new, more efficient lamp.

The maximum energy demand or load in a specified time period.

A mainly flat surface for transmitting radiant energy.

A structure or media that absorbs heat.

The generation of an electric current, when two conductors of different metals are joined at their ends to form a circuit, with the two junctions kept at different temperatures.

The area of glass that fits in the window frame.

The power output of a device under specific or nominal operating conditions.

The fine liquid or solid particles contained in combustion gases. The quantity and size of particulates emitted by cars, power and industrial plants, wood stoves, etc are regulated by the U.S. Environmental Protection Agency.

The loss of heat as the water circulates through a water heater tank and inlet and outlet pipes.

A popular term used to describe the increase in average global temperatures due to the greenhouse effect.

A solar energy concentrating technology that uses a linear receiver that tracks the focal area of a reflector or array of reflectors.

A construction material made by compressing earth in a form; used traditionally in many areas of the world and widely throughout North Africa and the Middle East.

A wheel that is designed to use the weight and/or force of moving water to turn it, primarily to operate machinery or grind grain.