2,400+ Definitions

HVAC GLOSSARY

Every HVAC term, acronym, and industry phrase — defined in plain English.

All A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
ACCA
ACCA (Air Conditioning Contractors of America) is the primary US…
AFUE
AFUE (Annual Fuel Utilization Efficiency) is the standard measure of…
Air Balancing
Air balancing is the process of adjusting an HVAC system…
Air Distribution
Air distribution describes how conditioned air is delivered to and…
Air Handler
An air handler (also called an air handling unit or…
ASHRAE
ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) is…
Blower Door Test
A blower door test is a diagnostic procedure that measures…
Boiler
A boiler is a heating system that heats water (or…
BTU
A BTU (British Thermal Unit) is the standard unit of…
Combustion Analysis
Combustion analysis is the process of measuring the byproducts of…
Compressor
The compressor is the heart of any refrigeration or HVAC…
Condensate Drain
The condensate drain system removes water that drips off the…
Condenser
The condenser is the outdoor unit of a split air…
Cooling Load
Cooling load is the rate at which heat must be…
COP (Coefficient of Performance)
Coefficient of Performance (COP) measures the efficiency of a heat…
Dehumidifier
A dehumidifier removes excess moisture from indoor air, reducing relative…
Duct Leakage
Duct leakage occurs when conditioned air escapes from supply ducts…
Ductwork
Ductwork is the network of metal, fiberglass, or flexible conduit…
Economizer
An economizer is a control system that uses outdoor air…
EER
EER (Energy Efficiency Ratio) measures an air conditioner or heat…
ENERGY STAR
ENERGY STAR is a certification program run by the U.S.…
EPA 608 Certification
EPA Section 608 Certification is the federal certification required by…
ERV (Energy Recovery Ventilator)
An Energy Recovery Ventilator (ERV) provides controlled fresh air ventilation…
Evaporator Coil
The evaporator coil is the indoor heat exchange component of…
Filter Drier
A filter drier is a sealed component in the refrigerant…
Fresh Air Intake
A fresh air intake brings outdoor air into the HVAC…
Furnace
A furnace is a forced-air heating system that burns fuel…
Geothermal Heat Pump
A geothermal heat pump (GHP), also called a ground-source heat…
Heat Exchanger
The heat exchanger in a gas furnace is the component…
Heat Load
Heat load (also called heating load or heat loss) is…
Heat Pump
A heat pump is an HVAC system that moves heat…
HRV (Heat Recovery Ventilator)
A Heat Recovery Ventilator (HRV) provides controlled fresh air ventilation…
HSPF2
HSPF2 (Heating Seasonal Performance Factor 2) is the federal standard…
Humidifier (Whole-House)
A whole-house humidifier adds moisture to the air distributed through…
Indoor Air Quality (IAQ)
Indoor Air Quality (IAQ) refers to the air quality within…
Load Calculation
A load calculation determines how much heating and cooling capacity…
Manual D
ACCA Manual D is the industry standard for residential duct…
Manual J
Manual J is the ACCA (Air Conditioning Contractors of America)…
Manual S
ACCA Manual S — Equipment Selection — is the companion…
MERV Rating
MERV (Minimum Efficiency Reporting Value) is the standard rating system…
Mini Split
A mini-split (also called a ductless mini-split or ductless heat…
NATE Certification
NATE (North American Technician Excellence) is the leading independent certification…
NFPA 70 (Electrical Code)
NFPA 70, the National Electrical Code (NEC), governs all electrical…
Packaged Unit
A packaged unit (also called a packaged system or rooftop…
Psychrometrics
Psychrometrics is the science of the thermodynamic properties of moist…
R-410A
R-410A is a hydrofluorocarbon (HFC) refrigerant that became the standard…
R-454B
R-454B (brand name Opteon XL41, manufactured by Chemours) is the…
Refrigerant
Refrigerant is the working fluid in an HVAC or refrigeration…