Glossary of HVAC Terms

Here’s a glossary of terms commonly used in the HVAC (Heating, Ventilation, and Air Conditioning) industry that will help you increase your knowledge of your HVAC system so you’re better equipped to ask questions and even diagnose problems yourself.

Air Handler: The indoor part of an HVAC system responsible for circulating conditioned air throughout a building.

BTU (British Thermal Unit): A unit of measurement for energy that is commonly used to describe the heating or cooling capacity of HVAC systems.

Compressor: A vital component in an air conditioning system that compresses refrigerant gas to increase its temperature and pressure.

Condenser Coil: Part of the outdoor unit in an air conditioning system where refrigerant releases heat and becomes a liquid.

Ductwork: A system of pipes or channels used to distribute air throughout a building, carrying heated or cooled air from the HVAC unit to various rooms.

Evaporator Coil: Located inside the air handler, this coil contains refrigerant that absorbs heat from the indoor air.

Furnace: A heating device that burns fuel (typically natural gas or oil) to heat air, which is then distributed through ducts.

HVAC: An acronym for Heating, Ventilation, and Air Conditioning, referring to systems that control temperature, humidity, and air quality in buildings.

Thermostat: A device that regulates the temperature by turning the HVAC system on or off based on the desired setpoint.

SEER (Seasonal Energy Efficiency Ratio): A measure of an air conditioner’s or heat pump’s cooling efficiency over a season. Higher SEER ratings indicate greater efficiency.

AFUE (Annual Fuel Utilization Efficiency): A measure of a furnace’s heating efficiency, typically expressed as a percentage.

Heat Pump: A system that can provide both heating and cooling by moving heat from one place to another, often used in regions with mild climates.

Zone Control: A system that divides a building into different zones, allowing temperature and airflow to be controlled independently in each area.

Humidifier: An accessory in an HVAC system that adds moisture to the indoor air to improve comfort and air quality.

MERV (Minimum Efficiency Reporting Value): A rating that measures the effectiveness of air filters in trapping airborne particles; higher ratings indicate better filtration.

Refrigerant: A substance used in air conditioning and refrigeration systems that changes from a gas to a liquid and back again to transfer heat.

Balancing: The process of adjusting airflow and temperature to ensure even distribution of heating or cooling throughout a building.

Load Calculation: A calculation used to determine the heating and cooling needs of a building, essential for sizing HVAC equipment correctly.

Ventilation: The process of introducing fresh outdoor air into a building to maintain air quality and remove stale or polluted air.

Return Air: The air drawn into the HVAC system from the building’s interior to be conditioned or filtered.

This glossary should help you better understand HVAC terminology and communicate effectively with HVAC professionals for your heating and cooling needs.