HVAC Terms and Definitions

HVAC Terms

AFUE – Annual Fuel Utilization Efficiency, a rating that reflects the efficiency of a gas furnace in converting fuel to energy. A rating of 80 means that approximately 80 percent of the fuel is utilized to provide warmth to your home, while the remaining 10 percent escapes as exhaust. BTU – British Thermal Unit. In scientific terms, it represents the amount of energy required to raise one pound of water one degree Fahrenheit. One BTU is the equivalent of the heat given off by a single wooden kitchen match. For your home, it represents the measure of heat given off when fuel is burned for heating or the measure of heat extracted from your home for cooling. Capacity – The output or producing capability of a piece of cooling or heating equipment. Cooling and heating capacity are normally referred to in BTUs. Compressor – The heart of an air conditioning or heat pump system. It is part of the outdoor unit that pumps refrigerant. The compressor maintains adequate pressure to cause refrigerant to flow in sufficient quantities in order to meet the cooling requirements of the system. Condenser Coil or Outdoor Coil – Located in the outdoor unit, the coil dissipates heat from the refrigerant, changing the refrigerant from vapor to liquid. Damper – Found in ductwork, this movable plate opens and closes to control airflow. Dampers are used effectively in zoning to regulate airflow to certain rooms. Ductwork – Pipes or channels that carry air throughout your home. Evaporator Coil – The coil that is inside your house in a split system. In the evaporator, refrigerant evaporates and absorbs heat from air passed over the coil. Heat Exchanger – A device for the transfer of heat energy from the source to the conveying medium. Humidifier – A device that injects water vapor into heated air as the air is expelled from the furnace. Humidity – The amount of moisture in the air. Air conditioners remove moisture for added comfort. HVAC – Heating, ventilation and air conditioning. Packaged System – A piece of air conditioning and heating equipment in which all components are located in one cabinet. Used occasionally in residential applications, the packaged unit is installed either beside or on top of the home. Refrigerant – A substance that produces a refrigerating effect while expanding or vaporizing. SEER – Seasonal Energy Efficiency Ratio, a rating that measures the cooling efficiency of a heat pump or air conditioner. The higher the number, the more efficient the unit. Split System – Refers to a comfort system configuration consisting of components in two locations. Common examples include an outside unit, such as an air conditioner, and an indoor unit, such as a furnace and coil. Thermostat – A temperature control device, typically found on a wall inside the home. It consists of a series of sensors and relays that monitor and control the functions of a heating and cooling system. Programmable thermostats allow you to program different levels of comfort for different times of the day.  
AV Heating and Cooling
11620 East US Highway 24 Sugar CreekMO64054 USA 
 • 816-796-0300