An incorporated right, liberty, privilege, or use of another entity's property, distinct from ownership, without profit or compensation; a right-of-way.

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

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

A device that tracks the movement of the sun; used to orient solar concentrating systems.

A device for converting a solid fuel to a gaseous fuel.

A wood or gas burning heating appliance that fits into the opening or protrudes on to the hearth of a conventional fireplace.

A thin sheet of material (metal) of a heat exchanger that conducts heat to a fluid.

A unit of rate of water evaporation equal to the evaporation per hour of 34.5 pounds of water at a temperature of 212 degrees Fahrenheit into steam at 212 degrees F.

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

The physically connected generation, transmission, and distribution facilities and components operated as a unit.

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

The total diffuse and direct insolation on a horizontal surface, averaged over a specified period of time.

A long, underground metal or plastic pipe through which air is drawn. As air travels through the pipe it gives up some of its heat to the soil, and enters the house as cooler air.

The ability of a building construction assembly (partition, wall, floor, etc.) to resist the passage of fire. The rating is expressed in hours.

The rate of heat production by a steady current in any part of an electrical circuit that is proportional to the resistance and to the square of the current, or, the internal energy of an ideal gas depends only on its temperature.

A water heater that heats water before it is directly distributed for end use as required; a demand water heater.

A form of thermal energy resulting from combustion, chemical reaction, friction, or movement of electricity. As a thermodynamic condition, heat, at a constant pressure, is equal to internal or intrinsic energy plus pressure times volume.

A device for converting continuous circular motion into reciprocating rectilinear motion.

The path followed by electrons from a generation source, through an electrical system, and returning to the source.

The quantity of heat produced to change a unit weight of a liquid to vapor with no change in temperature.