The process of modifying a building's structure.

An electrochemical device that converts chemical energy directly into electricity.

A type of anaerobic digester that has a mechanical mixing system and where temperature and volume are controlled to maximize the anaerobic digestion process for biological waste treatment, methane production, and odor control.

Large, flat boxes with glass covers and dark-colored metal plates inside that absorb and transfer solar energy to a heat transfer fluid.

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.

A device used to maintain a specified humidity in a conditioned space.

A thermostat that can be set to automatically lower temperatures in an unoccupied house and raise them again before the occupant returns.

A unit of mass equal to 1,000 kilograms or 2,204.6 pounds.

A term used to describe short and long-term affects on the Earth's climate as a result of human activities such as fossil fuel combustion and vegetation clearing and burning.

A hydropower facility that stores water in a reservoir during high-inflow periods to augment water during low-inflow periods. Storage projects allow the flow releases and power production to be more flexible and dependable. Many hydropower project operati ...

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

The amount of fuel necessary to generate one kilowatt-hour of electricity.

A self-contained toilet that use the process of aerobic decomposition (composting) to break down feces into humus and odorless gases.

Water heated for residential washing, bathing, etc.

The losses that result from inherent resistance in electrical conductors and transformation inefficiencies in distribution transformers in a transmission and distribution network.

The sum of sensible heat and latent heat in a substance above a base temperature, typically 32 degrees Fahrenheit.

An amount to be paid for energy periodically by a customer without regard to demand or energy consumption.

The component of a central air conditioner that is designed to remove heat absorbed by the refrigerant and transfer it outside the conditioned space.

Any material that can be burned to make energy.

An empirical measure of the quantity of light. It is based upon the spectral sensitivity of the photosensors in the human eye under high (daytime) light levels. Photometrically it is the luminous flux emitted with a solid angle (1 steradian) by a point so ...