A gas that does not react with other substances; e.g. argon or krypton; sealed between two sheets of glazing to decrease the U-value (increase the R-Value) of windows.

A gas or liquid used to move heat energy from one place to another; a refrigerant.

A valve used to mix heated water with cold in a heating system to provide a desired water temperature for end use.

A hydrocarbon gas obtained from underground sources, often in association with petroleum and coal deposits. It generally contains a high percentage of methane, varying amounts of ethane, and inert gases; used as a heating fuel.

A pole used to assist in raising a tower.

A mainly flat surface for transmitting radiant energy.

Any device (or plant) that follows the sun's apparent movement across the sky.

A seal used to prevent the leakage of fluids, and also maintain the pressure in an enclosure.

These lights use an electrically heated filament to produce light in a vacuum or inert gas-filled bulb.

A type of water heater that has no storage tank thus eliminating storage tank standby losses. Cold water travels through a pipe into the unit, and either a gas burner or an electric element heats the water only when needed.

A building energy auditing technique for locating areas of low insulation in a building envelope by means of a thermographic scanner.

The ratio of the percentage change in the quantity of a good or service demanded to the percentage change in the price.

A salt, sodium sulfate decahydrate, that melts at 90 degrees Fahrenheit; a component of eutetic salts that can be used for storing heat.

A type of water heater that circulates water through a heat exchanger in a boiler. The heated water then flows into an insulated storage tank.

A house built using passive solar design techniques.

Individual rooms or zones in a building where temperature is controlled separately from other rooms or zones.

A measure of the amount of energy lost during the generation, transmission, and distribution of electricity.

The ratio of the minimum amount of work or energy required to perform a task to the amount actually used.

This is a national organization dedicated to representing the interests of cooperative electric utilities and the consumers they serve. Members come from the 46 states that have an electric distribution cooperative.

The minimum temperature at which combustion of a solid or fluid can occur.