The number of degrees per day that the daily average temperature (the mean of the maximum and minimum recorded temperatures) is below a base temperature, usually 65 degrees Fahrenheit, unless otherwise specified; used to determine indoor space heating req ...

Standardized weights or volumes for heating fuels.

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

The rate of heat flow required to maintain a specific indoor temperature; usually measured in Btu per hour.

The coldest months of the year; months where average daily temperatures fall below 65 degrees Fahrenheit creating demand for indoor space heating.

The measure of seasonal or annual efficiency of a heat pump operating in the heating mode. It takes into account the variations in temperature that can occur within a season and is the average number of Btu of heat delivered for every watt-hour of electri ...

The amount of heat produced from the complete combustion of a unit of fuel. The higher (or gross) heating value is that when all products of combustion are cooled to the pre-combustion temperature, water vapor formed during combustion is condensed, and ne ...

All the components of the appliance used to condition interior air of a building.

The utilization of solar energy through photosynthesis.

A device used to simulate the angle of the sun for assessing shading potentials of building structures or landscape features.

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

Any process that uses solar radiation to produce useful heat.

Site planning that accounts for natural solar heating and cooling processes and their relationship to building shape, orientation, and siting.

An instrument for measuring solar radiation.

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

A solar energy concentrating technology that uses a linear receiver that tracks the focal area of a reflector or array of reflectors.

A measure of the number of cycles or wavelengths of electrical energy per second; U.S. electricity supply has a standard frequency of 60 hertz.

A region of electrical contact between two different materials.

A lamp that consists of a sealed arc tube inside a glass envelope, or outer jacket. The inner arc tube is filled with elements that emit light when ionized by electric current. A ballast is required to provide the proper starting voltage and to regulate c ...

A type of High-Intensity Discharge (HID) lamp that uses sodium under high pressure as the primary light-producing element. These high efficiency lights produce a golden white color and are used for interior industrial applications, such as in warehouses a ...