Every industry has its own terminology, and if you don’t understand those terms, it’s almost like trying to decipher a foreign language. The HVAC industry is no different, and if you’re trying to describe a problem or listen to a technician, it can be confusing. To clear things up a little, we will explain the meanings of some basic HVAC terminology in this article in alphabetical order for easy reference:

AC: Alternating current where the polarity is continually reversed.

AFUE: American Fuel Utilization Efficiency, which is a measurement used to determine the efficiency of a furnace. Essentially this is an equation that compares the heating input (fuel consumed) to the heating output.

Air Conditioner: A device used to alter the temperature, humidity, and air quality inside a home or business. Cheaper units typically alter the temperature and dehumidify a little. More elaborate units can improve the indoor air quality (IAQ) and dehumidify the entire home to a high standard.

Airflow Volume: The volume of air that is circulated in a certain space which is measure in cubic feet per minute (cfm).

Air Handler: The indoor unit of an air conditioning system that includes the fan and condenser/evaporator coil. The condenser coil is used in winter, and the evaporator coil is used during the warmer summer months.

BTU: British Thermal Unit, a unit of measurement for the amount of heat required to lower or raise the temperature of a pound of water by 1ºF.

BTU/h: The amount of BTUs used in a single hour.

Burner: A device used to combust air and gas (or other fuel) via a burner orifice.

Capacity: The total output of a heating or cooling unit measure in BTU/h.

Charging: Typically used in the phrase “charging the system,” this refers to the addition of refrigerant or coolant to make the air conditioner work efficiently.

Compressor: A pump that puts the refrigerant under pressure to remove heat from the home.

Condensate Pan: A drainage pan where the condensate (water) collected from the air in the home is deposited and then drained into a connected drain line.

Condenser Coil: The outdoor unit of an air conditioner, which removes the excess heat from the circulating refrigerant to make the home feel cooler.

Condenser Fan: A fan that moves the air across the condenser coil to speed up the removal of heat from the refrigerant.

DC: Direct current, which shifts in one direction regularly.

Damper: A device that opens and closes plates inside the ductwork to direct air to specified zones to control the airflow efficiently.

Degree-Day: A number calculated by deducting the outdoor average temperature from 65ºF. This calculation helps to find the amount of heating or cooling to make the internal space feel comfortable.

Dehumidifier: A dedicated unit that removes the humidity from the indoor air.

Downflow Furnace: A furnace that has a top mounted intake that leads to an air discharge located at the bottom part of the furnace.

Ductwork: This is the network of ducts that deliver the treated air from the HVAC system throughout the building.

Indoor Coil: Also known as an evaporator coil, this component absorbs heat from the air to change the refrigerant from a liquid into a vapor. This is an essential part of the process to remove heat from the space and make it feel cooler.

Expansion Valve: A valve that measures the level of refrigerant present in the system using pressure or temperature control.

Flue: A specialized vent that removes unwanted combustion byproducts from the furnace to keep the building safe to use.

Furnace: The most common heating unit found in buildings, the furnace creates combustion to generate heat and then circulates this with a fan.

Heating Coil: A component that’s a source of heat that is found in the heating system.

Heat Pump: A pump that, despite its name, actually assists the heating and cooling processes. It transfers heat between a pair of reservoirs to make the system more efficient.

HSPF: Heating Seasonal Performance Factor, which is a term that defines the efficiency of a residential heat pump.

Humidifier: A unit that increases the humidity in the building by adding moisture.

Humidistat: A device that accurately measurer the level of humidity in a space. This can be a standalone unit, or it may be part of a system to turn the humidifier on as required automatically.

Package Unit: A smaller heating and cooling system that can be bundled together in one outdoor unit.

Radiant Floor: An under floor heating system that circulates fluids.

Reciprocating Compressor: A compressor unit that uses a piston to put the refrigerant under pressure.

Refrigerant: A fluid used in air conditioners, refrigerators, and heat pumps to remove heat from an interior space.

Associations and Organizations

Here are some common associations and organizations that are connected to the HVAC industry:

ACCA: Air Conditioning Contractors of America, a non-profit that represents HVAC contractors.

AGA: America Gas Association Inc., a group that represents over 200 natural gas delivery companies.

AHRI: Air Conditioning, Heating, and Refrigeration Institute, an HVACR and water heating trade association.

ASHRAE: American Society of Heating, Refrigeration and Air Conditioning Engineers, a society dedicated to improving air quality, energy efficiency, and sustainability in the HVAC industry.

Energy Star: A voluntary EPA program to improve energy efficiency.

NATE: North American Technician Excellence, a non-profit certification group for HVAC professionals.

In Conclusion

As you can see, the HVAC industry has a lot of acronyms, associations, and organizations, and it can be hard to remember them all. Of course, when you’re speaking with an HVAC technician, you won’t need every term listed here. But, understand while some of this terminology may be helpful, if you’re not sure, don’t be afraid to ask questions. A local HVAC technician will be happy to explain something in detail, and this will help you to make informed decisions about your HVAC system.

If your HVAC system needs some attention, contact your local heating and cooling specialist for expert help and advice today.