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

A wood or gas burning appliance that is primarily used to provide ambiance to a room. Conventional, masonry fireplaces without energy saving features, often take more heat from a space than they put into it.

A building energy auditing technique for locating areas of low insulation in a building envelope by means of a thermographic scanner.

A passive solar heating system in which the sun warms a heat storage element, and the heat is distributed to the interior space by convection, conduction, and radiation.

A mainly flat surface for transmitting radiant energy.

A seal used to prevent the leakage of fluids, and also maintain the pressure in an enclosure.

Individual rooms or zones in a building where temperature is controlled separately from other rooms or zones.

A salt, sodium sulfate decahydrate, that melts at 90 degrees Fahrenheit; a component of eutetic salts that can be used for storing heat.

An elementary particle of an atom with a negative electrical charge and a mass of 1/1837 of a proton; electrons surround the positively charged nucleus of an atom and determine the chemical properties of an atom.

The price paid for goods or services at the time of a transaction; a price that has not been adjusted to account for inflation.

An instrument for measuring solar radiation.

A solar energy conversion device that has a bowl shaped dish covered with a highly reflective surface that tracks the sun and concentrates sunlight on a fixed absorber, thereby achieving high temperatures, for process heating or to operate a heat (Stirlin ...

The minimum temperature at which combustion of a solid or fluid can occur.

A heating system that uses only outside air for combustion and vents combustion gases directly to the outdoors. These systems are less likely to backdraft and to negatively affect indoor air quality.

The process of cooling by which a heat absorbing media absorbs heat from one source and radiates the heat away.

The amount of heat that a material can absorb and store.

Any device (or plant) that follows the sun's apparent movement across the sky.

A valve used to mix heated water with cold in a heating system to provide a desired water temperature for end use.

Solar collector thermal performance ratings based on collector efficiencies, usually expressed in Btu per hour for solar collectors under standard test or operating conditions for solar radiation intensity, inlet working fluid temperatures, and ambient te ...

In alternating current, the current goes from zero potential or voltage to a maximum in one direction, back to zero, and then to a maximum potential or voltage in the other direction. The number of complete cycles per second determines the current frequen ...