The indoor part of an air conditioner or heat pump that moves cooled or heated air throughout the ductwork of your home. An air handler is usually a furnace or a blower coil.

A device for filtering particles of dust, soot, etc., from the air passing through it, especially one protecting the air inlet of an internal combustion engine.

An industry trade association that develops standards for measuring and certifying product performance. For instance, ARI Standard 270 provides guidelines for establishing sound levels for outdoor air-conditioning equipment.

A measure of furnace heating efficiency. The higher the AFUE, the more efficient the furnace.

Microscopic living organisms suspended in the air that grow and multiply in warm, humid places.

A measurement of heat energy. One Btu is the amount of heat required to raise one pound of water by one degree Fahrenheit. The higher the Btu rating, the greater the heating capacity of the system.

British thermal units per hour.

A carbon footprint is historically defined as "the total sets of greenhouse gas emissions caused by an organization, event, product or individual.

An odorless, colorless, tasteless, poisonous and flammable gas produced when carbon burns with insufficient air.

System in which air is cooled at a central location and distributed to and from rooms by one or more fans and a series of ducts.