A type of heating system that provides heat from the resistance of an electrical current flowing through a conductor.

A device that removes airborne particles from breathable air. Negative ions are produced and give up their negative charge to the particles. These new negative particles are then attracted to the positive particles surrounding them. This accumulation proc ...

A building that is elongated in the east-west direction, with the majority of the windows on the south side. The area of the windows is generally limited to about 7% of the total floor area. A sun-tempered design has no added thermal mass beyond what is a ...

The amount of energy absorbed (or converted) by a solar collector (or photovoltaic cell or module) over a 15 minute period.

Insulation made from rockwool fibers, fiberglass, cellulose fiber, vermiculite or perlite minerals, and composed of loose fibers or granules can be applied by pouring directly from the bag or with a blower.

The amount of heated air, or heating capacity, to be supplied by a heating system; usually the maximum amount to be delivered based on a specified number of heating degree days or design outside temperature.

One pound of water in vapor phase; is NOT steam pressure, which is expressed as pounds per square inch (psi).

A type of furnace in which fuel is spread, automatically or mechanically, across the furnace grate.

A load management objective that moves loads from on-peak periods to off-peak periods.

A system of astronomical time in which the sun crosses the true north-south meridian at 12 noon, and which differs from local time according to longitude, time zone, and equation of time.

A frequently used room or area that is maintained at a more comfortable level than the rest of the house; also known as a "warm room."

A light control device that allows light levels to be manually adjusted. A dimmer can save energy by reducing the amount of power delivered to the light while consuming very little themselves.

The process of converting municipal solid waste to energy and/or recovering materials for recycling.

A device that that converts direct current electricity (from for example a solar photovoltaic module or array) to alternating current for use directly to operate appliances or to supply power to a electricity grid.

The device in an air conditioner or heat pump in which the refrigerant condenses from a gas to a liquid when it is depressurized or cooled.

The push or pull that alters the motion of a moving body or moves a stationairy body; the unit of force is the dyne or poundal; force is equal to mass time velocity divided by time.

Any material that can be burned to make energy.

The vacancy where an electron would normally exist in a solid; behaves like a positively charged particle.

To influence the demand on a power source.

A system in which a working fluid is used over and over without introduction of new fluid, as in a hydronic heating system or mechanical refrigeration system.