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.

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.

This designates the resistance of a material to heat conduction. The greater the R-value the larger the number.

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 ...

A wood-burning appliance for space and/or water heating and/or cooking.

A device used to measure total incident solar radiation (direct beam, diffuse, and reflected radiation) per unit time per unit area.

The transmission of electricity through power lines.

Materials with various qualities that are applied to glass windows before installation. These coatings reduce radiant heat transfer through the window and also reflects outside heat and a portion of the incoming solar energy, thus reducing heat gain. The ...

An electricity powered device that extracts available heat from one area (the heat source) and transfers it to another (the heat sink) to either heat or cool an interior space or to extract heat energy from a fluid.

These lights use an electrically heated filament to produce light in a vacuum or inert gas-filled bulb.

One thousand kilowatt-hours or 1 million watt-hours.

A gas or liquid used to move heat energy from one place to another; a refrigerant.

The ratio of fuel energy input as heat per unit of net work output; a measure of a power plant thermal efficiency, generally expressed as Btu per net kilowatt-hour.

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 ...

The change in direction of a ray of light when it passes through one media to another with differing optical densities.

The maximum instantaneous wind speed (or velocity) that occurs within a specific period of time or interval.

One thousand kilowatts, or 1 million watts; standard measure of electric power plant generating capacity.

The ability to send or wheel electric power to a customer over a transmission and distribution system that is not owned by the generator (seller) of the power.

In a given electrical circuit, the amount of current in amperes (i) is equal to the pressure in volts (V) divided by the resistance, in ohms (R).

The unit price of a good or service estimated from some base year in order to provide a consistent means of comparison.