An air conditioning system that has two ducts, one is heated and the other is cooled, so that air of the correct temperature is provided by mixing varying amounts of air from each duct.

The measure of overall efficiency for a variety of appliances. For water heaters, the energy factor is based on three factors: 1) the recovery efficiency, or how efficiently the heat from the energy source is transferred to the water; 2) standby losses, o ...

A solar energy system that produces electricity with a PV module, and collects thermal energy from the module for heating. There are no commercially available systems available (as of 11/97).

Energy derived from resources that are regenerative or for all practical purposes can not be depleted. Types of renewable energy resources include moving water (hydro, tidal and wave power), thermal gradients in ocean water, biomass, geothermal energy, so ...

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

A combustion heating appliance in which heat is captured from the burning of a fuel for distribution, comprised mainly of a combustion chamber and heat exchanger.

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 type of hydroelectric facility that uses the river flow with very little alteration and little or no impoundment of the water.

The ratio of power produced by a wind energy conversion device to the power in a reference area of the free windstream.

An exterior door that protects the primary door.

A free and mobile conduction electron or hole in a semiconductor.

A class of energy producer that produces both heat and electricity from a single fuel.

A thermostat that can be set to automatically lower temperatures in an unoccupied house and raise them again before the occupant returns.

In reference to a wind turbine, a condition when the rotor stops turning.

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

A tubular material used to encase and protect one or more electrical conductors.

A device that reduces heat loss at night and during cloudy periods and heat gain during the day in warm weather. A movable insulator could be an insulative shade, shutter panel, or curtain.

A term used to describe short and long-term affects on the Earth's climate as a result of human activities such as fossil fuel combustion and vegetation clearing and burning.

The process of modifying a building's structure.

A solar energy collection device consisting of containers of water located on a roof that absorb solar energy during the day so that the heat can be used at night or that cools a building by evaporation at night.