A measure of the electrical resistance of a material equal to the resistance of a circuit in which the potential difference of 1 volt produces a current of 1 ampere.

A unit of measurement for the ability of a material to retard the diffusion of water vapor at 73.4 F (23 C). A perm, short for permeance, is the number of grains of water vapor that pass through a square foot of material per hour at a differential vapor p ...

The amount of energy derived from an electrical source per unit quantity of electricity passing through the source.2. Electrical potential; voltage.

A construction element that inhibits termites from entering building foundations and walls.

A battery-powered electrically driven vehicle.

An air heater in which air is blown over electric resistance heating coils.

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

The ratio of a photovoltaic cell's actual power to its power if both current and voltage were at their maxima. A key characteristic in evaluating cell performance.

The sum of all the costs both recurring and nonrecurring, related to a product, structure, system, or service during its life span or specified time period.

A device consisting of two dissimilar conductors with their ends connected together. When the two junctions are at different temperatures, a small voltage is generated.

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

A curve that indicates the number of hours per year that specific wind speeds occur.

A layer of semiconductor material, such as copper indium diselenide or gallium arsenide, a few microns or less in thickness, used to make solar photovoltaic cells.

A mechanical/electrical device used to pull air out of an interior space; usually located in the highest location of a building, in the ceiling, and venting to the attic or directly to the outside.

A class of power generator that is not a regulated utility and that has generating plants for the purpose of supplying electric power required in the conduct of their industrial and commercial operations.

The transfer of heat through a material by the transfer of kinetic energy from particle to particle; the flow of heat between two materials of different temperatures that are in direct physical contact.

The effect of cooling by the radiation of heat from a building to the night sky.

The wind speed with 50 percent probability of occurring.

A heating system, such as a solar water heater or geothermal heatpump, in which the working fluid is heated and used directly; in an open-loop solar system, the domestic water is circulated in the collector loop.

A device used to control temperatures; used to control the operation of heating and cooling devices by turning the device on or off when a specified temperature is reached.