The amount of visible light that passes through the glazing material of a window, expressed as a percentage.

The process in which a solid fuel is converted into a gas; also known as pyrolitic distillation or pyrolysis. Production of a clean fuel gas makes a wide variety of power options available.

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 federal agency established in 1933 to develop the Tennessee river valley region of the southeastern U.S., and which is now nation's largest power producer.

The wind speed with 50 percent probability of occurring.

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

The unit price and quantity to which it applies as specified in a rate schedule or contract.

A measure of air purity that is equal to one complete air change (in an interior space).

The maximum load that a device is capable of carrying.

The cutting of a grid pattern of grooves in a semiconductor material, generally for the purpose of making interconnections.

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.

Waste material from households and businesses in a community that is not regulated as hazardous.

Solid fuels made from primarily wood sawdust that is compacted under high pressure to form small (about the size of rabbit feed) pellets for use in a pellet stove.

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

Any gaseous, liquid, or solid fuel used for indoor space heating.

A device for converting mechanical energy to electrical energy.

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

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 heat storage system that uses a heat storage medium, and where the additional or removal of heat results in a change in temperature.