The unoccupied, and usually unfinished and unconditioned space between the floor, foundation walls, and the slab or ground of a building.

The highest wind speed at which a wind turbine stops producing power.

A measure of the moisture content of air; may be expressed as absolute, mixing ratio, saturation deficit, relative, or specific.

The amount of money required to secure a specified cash flow at a future date at a specified return.

This type of heat pump is known as an air-to air system.

The relative extent that energy is required for a process.

Materials with high thermal energy storage capacity contained in or part of a building's walls, floors, or freestanding elements.

The physical process by which a liquid or solid is transformed into the gaseous state. For this process a mechanical device uses the outside air's heat to evaporate water that is held by pads inside the cooler. The heat is drawn out of the air through thi ...

A utility owned by stockholders or other investors; sometimes referred to as a private utility, in contrast to a public utility that is owned by a government agency or cooperative.

A building heating, ventilation, and/or air conditioning system that distributes conditioned air to individual zones or rooms.

Waste water from a household source other than a toilet. This water can be used for landscape irrigation depending upon the source of the greywater.

The ratio of actual power being used in a circuit, expressed in watts or kilowatts, to the power that is apparently being drawn from a power source, expressed in volt-amperes or kilovolt-amperes.

A device or material with a high resistance to electricity flow.

One millionth of a meter (10-6 m).

A concrete pad that sits on gravel or crushed rock, well-compacted soil either level with the ground or above the ground.

A curve that displays load values on the horizontal axis in descending order of magnitude against the percent of time (on the vertical axis) that the load values are exceeded.

In reference to solar thermal collectors, the condition where the heat transfer fluid is flowing through the collector loop under normal operating conditions.

A nationally recognized energy rating program that gives builders, mortgage lenders, secondary lending markets, homeowners, sellers, and buyers a precise evaluation of energy losing deficiency's in homes. Builders can use this system to gauge the energy q ...

Infrared or radiant heat.

Any liquid petroleum product burned for the generation of heat in a furnace or firebox, or for the generation of power in an engine. Domestic (residential) heating fuels are classed as Nos. 1, 2, 3; Industrial fuels as Nos. 4, 5, and 6.