Glossary of Terms

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Capacity: The ability of a heating or cooling system to heat or cool a given amount of space. For heating, this is usually expressed in BTU’s or tons. For cooling, it is usually expressed in tons.

Central Air Conditioning or HVAC system: Mechanical system in which air is treated at a central location and is distributed to and from rooms by one or more fans and a series of ducts.

CFM: Stands for Cubic Feet per Minute. A measurement of airflow that indicates how many cubic feet of air pass by a stationary point in one minute. The higher the number, the more air is being forced through a system.

Closed-Loop geothermal heat pump system: A geothermal heat pump system that uses a loop of buried polyethylene or plastic pipe as a heat exchanger. Loops can be horizontal or vertical. Loops can be buried in ground or in bodies of water.

COP (Coefficient of Performance): The ratio of heating or cooling provided by a heat pump to the energy consumed by the system under designed operating conditions. In other words, the ratio of output to input. The higher the COP, the more efficient the system.

Compressor: Part of a heat pump or air conditioner unit that controls the pressure applied to the refrigerant, necessary for taking in heat to warm your home or getting rid of heat to cool your home.

Condenser: A heat exchanger in which hot, pressurized (gaseous) refrigerant is condensed by transferring heat to cooler surrounding air, water, or earth.

Condenser Coil: Part of the outdoor portion of a split-system air conditioner or heat pump that either releases or collects heat, depending on the time of year.

Cycling Losses: Start-up and shut-down energy losses. Oversizing a heating or cooling system increases cycling losses.

Damper: A type of “valve” used in duct work that opens or closes to control airflow. Used in zoning to control the amount of warm or cool air in entering certain areas in a home or business.

DB: Decibels (db) are a unit of measuring the intensity of noise.

Dehumidifer: An indoor air quality device that removes humidity from indoor air. Often used in basements or crawl spaces. Some types of dehumidifier units are designed to be installed with air conditioning systems to provide additional moisture removal.