The outer casing of a window that sits in a designated opening of a structure and holds the window panes in place.

The gaseous byproducts of the combustion of a fuel.

Fuels formed in the ground from the remains of dead plants and animals. It takes millions of years to form fossil fuels. Oil, natural gas, and coal are fossil fuels.

The water content of a substance (a solid fuel) as measured under specified conditions being the: Dry Basis, which equals the weight of the wet sample minus the weight of a (bone) dry sample divided by the weight of the dry sample times 100 (to get percen ...

A heat source, such as a space heater, used to provide more heat than that provided by a primary heating source.

A common utility monetary measure equal to one-thousandth of a dollar or a tenth of a cent.

A column of gas at standard conditions of temperature and pressure (32 degrees Fahrenheit and one atmosphere).

The storage of compressed air in a container for use to operate a prime mover for electricity generation.

A tubular material used to encase and protect one or more electrical conductors.

The height above the ground that a horizontal axis wind turbine's hub is located.

Electric power plant or utility capacity on line and running at low power in excess of actual load.

The quantity of heat required to change the temperature of one unit weight of a material by one degree.

A small groove scribed into the surface of a solar photovoltaic cell which is filled with metal for contacts.

A smokestack or flue for exhausting the products of combustion from a combustion appliance.

A solid-state electrical device that converts light directly into direct current electricity of voltage-current characteristics that are a function of the characteristics of the light source and the materials in and design of the device. Solar photovoltai ...

A high-intensity discharge lamp type that uses mercury and several halide additives as light-producing elements. These lights have the best Color Rendition Index (CRI) of the High-Intensity Discharge lamps. They can be used for commercial interior lightin ...

The temperature that a system is designed to maintain (inside) or operate against (outside) under the most extreme conditions.

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.

An electrical device that resists electric current flow.

The flow rate in these systems is 1/8 to 1/5 the rate of most solar water heating systems. The low-flow systems take advantage of stratification in the storage tank and theoretically allows for the use of smaller diameter piping to and from the collector ...