A drag-type wind machine that can react to wind from any direction.

A power line for supplying electricity within a specified area.

Those elements of building used to control the interior climate.

Gasoline fuel additives such as ethanol, ETBE, or MTBE that add extra oxygen to gasoline to reduce carbon monoxide pollution produced by vehicles.

A total life cycle cost divided into equal amounts.

To heat a gaseous mixture to the temperature at which combustion takes place.

A device mounted in the vent connector that closes the vent when the heating unit is not firing. This traps heat inside the heating system and house rather than letting it draft up and out the vent system.

A facility or piece of equipment that produces electricity.

The prescribed level of pollutants allowed in outside or indoor air as established by legislation.

A tube in which combustion gases from a combustion appliance are vented out of the appliance to the outdoors.

The unit of illuminance equivalent to 1lumen per square meter.

A light source composed of a metal base, a glass tube filled with an inert gas or a vapor, and base pins to attach to a fixture.

The pressure of the steam or water in a boiler as measured; usually expressed in pounds per square inch gauge (psig).

A building energy auditing technique used to determine and/or locate air leaks in a building shell or envelope.

A charge for the maximum rate at which energy is used during peak hours of a billing period. That part of a utility service charged for on the basis of the possible demand as distinguished from the energy actually consumed.

The heat absorbed or released when a substance undergoes a change in temperature.

Turbines in which the rotor speed increases and decreases with changing wind speed, producing electricity with a variable frequency.

A type of insulation, composed of small diameter pink, yellow, or white glass fibers, formed into blankets or batts, or used in loose-fill and blown-in applications.

A unit of electrical capacitance; the capacitance of a capacitor between the plates of which there appears a difference of 1 Volt when it is charged by one coulomb of electricity.

A type of (geothermal) heat pump that uses well (ground) or surface water as a heat source. Water has a more stable seasonal temperature than air thus making for a more efficient heat source.