Glossary for HVAC Terms


The heating, ventilation and air conditioning industry is a complicated one with many different certifications and licenses that one must gain before performing repair work or maintenance as a contractor. Similarly, as a homeowner, there are many things that you need to know before embarking on the installation of heating and air conditioning units, including how to select the top quality products, and what to look for when hiring contractors to do the work. This is where a glossary of HVAC terms comes in handy, so that you can confidently get your installations done, choose the right products and understand the various processes that are involved.

Useful HVAC Definition and Terms

There are a number of services and products in the ventilation, heating and air conditioning industry that you might not recognize or understand, so to help you make the best choices, here is a glossary of HVAC terms that are used regularly.


  • Advanced Reciprocating Compressor: A type of refrigerant compressor that provides a more efficient form of cooling.
  • Air Handler: The part of your heating and air conditioner unit that forces the air through the ducts in your home.
  • Annual Fuel Utilization Efficiency AFUE: The indication of how much your furnace’s heat is being converted into energy, in terms of percentage.
  • British Thermal Unit BTU: A unit used to measure the heat given off or extracted from your home, when fuel is combusted.
  • Carbon Monoxide: A dangerous, odorless and colorless gas.
  • Compressor: Controls the pressure of the refrigerant necessary for releasing heat and taking in heat, therefore cooling and heating your home.
  • Condenser Coil: The coil condenses the gas form of the refrigerant back into a liquid so that heat can be expelled. It is part of the outside of a split system heat pump or air conditioner.
  • Continuous Fan Switch: This feature allows the fan on an oil furnace to blow non-stop to improve the efficiency of the system and maintain consistent temperatures.
  • Damper: This valve is used in the duct work of the HVAC systems to control the airflow. It is also used to control which rooms in your home get warm or cool air in zoning.
  • Downflow: This furnace pulls cool air from above and moves the warm air to the bottom.
  • Ductwork: This important part of a home heating and cooling system is used to transfer air to the vents in your home from the air handler.
  • Electronic Air Cleaner EAC: A device that filters air contaminants and large particles indoors, after which it pulls out magnetized particles such as bacteria and viruses and deposits them to a collector plate.
  • Energy Efficiency Ratings EER: This rating is determined by dividing the BTU output of a product by the product’s wattage.
  • Energy Saver Switch: The switch turns the AC’s fan and compressor off and on in order to reduce energy use.
  • Energy Star: This governmental backed program helps protect the environment by giving ratings to energy efficient products.
  • Evaporator Coil: This indoor coil is part of the split-system heat pump or air con unit that dehumidifies and cools the air, by absorbing the heat and converting the liquid refrigerant into gas so it can warm the air inside.
  • Fan Coil: This is an internal part of the heat pump system used instead of an evaporator coil and furnace to heat or cool a home.
  • Heat Exchanger: This part of the furnace transfers heat to any air nearby, which is then distributed through your home.
  • Heating Seasonal Performance Factor HSPF: This is how the heating efficiency of heat pumps is measured, with the higher numbers being better.
  • Humidistat: This control allows you to maintain humidity at a fixed point manually.
  • North American Technician Excellence NATE: Company in charge of certification of HVAC contractors and licensing.

Common Product Definitions and Descriptions

You will find these popular, common air conditioning units, heating products, and other state-of-the-art systems by various top manufacturers including Bryant, and Carrier with an HVAC definition of each type.


  • AeroQuiet: This efficient system offers special sound deadening features in the top, fan system and within the cabinet for reduced noise
  • Beckett Burner: A type of burner in your oil furnace manufactured by Beckett according to exact Bryant specifications.
  • Check-Flo-Rater: A special metering device that effectively controls the flow of refrigerant.
  • DuraGuard: This is a Bryant innovation which increases the durability of units and protects them from harsh conditions.
  • Evolution Control: This product allows you to set a 7 day program for humidity, temperature, and air quality.
  • Greenspeed Intelligence: This Carrier product maximizes the performance of HVAC units through adaptable speed technology.
  • Perfect Humidity: This is the proprietary humidity management developed by Bryant.
  • QuieTech: This product reduces noise while it produces heat.
  • Serpentuff: This Carrier/Bryant heat exchanger product features patented polypropylene laminate, which can extract nearly all the heat from your system.
  • Thermidistat: This device controls the temperature inside and outside the home to effectively maintain the humidity levels set by the homeowner.
  • Thermostatic Expansion Valve TXV: This device measures the flow of liquid refrigerant that goes into the evaporator so that is precisely matches the rate being boiled off.
  • Zone Perfect Plus: Works together with properly matched HVAC products to enhance energy efficiency by about 30%.

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