2,400+ Definitions

HVAC GLOSSARY

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

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Fluorescent Leak Dye
Fluorescent leak dye is a visible tracer chemical added to…
Flush Mount Solar
Flush mount solar describes panels installed parallel to roof surfaces…
Flushing
Flushing is the process of circulating a cleaning agent or…
Flux Residue Removal
The post-brazing process of cleaning flux from joints using hot…
Foaming Coil Cleaner
Foaming coil cleaner is a specialized chemical product that expands…
Food Service HVAC
Food service HVAC systems manage temperature, humidity, and air quality…
Forced Air Furnace
A forced air furnace is a heating system that uses…
Forced Draft
A combustion air arrangement in which a blower pushes air…
Forced Draft Cooling Tower
A forced draft cooling tower uses a fan mounted at…
Formaldehyde
Formaldehyde is a colorless, pungent gas released from building materials,…
Formaldehyde Sources
Formaldehyde Sources are building materials and furnishings that emit formaldehyde…
Fossil Fuel Switchover Point
The specific outdoor temperature at which a dual-fuel system’s controls…
Four Pipe System
A four-pipe system is a hydronic HVAC distribution configuration that…
Four Way Reversing Valve
A four-way reversing valve is an electromechanical component used in…
Four-Pipe System
A hydronic distribution arrangement that maintains dedicated supply and return…
fractionation
The separation of refrigerant blend components in the liquid and…
Framing Factor
The fraction of a wall or roof assembly cross-section occupied…
Free Cooling
Free cooling leverages outdoor air or water sources to remove…
Free Cooling (Waterside)
A mode of chiller plant operation in which cool ambient…
Free Cooling Coil
A free cooling coil transfers heat directly from a building…
Free Cooling Mode
Free Cooling Mode uses available outdoor air or water resources…
Freeze Up
Freeze up occurs when ice accumulates on the evaporator coil,…
Freezer
A freezer is a refrigeration appliance or system that maintains…
Freon History
Freon is the trademark name for chlorofluorocarbon (CFC) refrigerants developed…
Fresh Air Intake
A fresh air intake brings outdoor air into the HVAC…
Friction Rate
Friction rate is the pressure loss per 100 feet of…
Frost Control Mode
An operational strategy used in HRVs and ERVs during very…
Frost-Free Evaporator
An evaporator coil designed and operated with periodic automatic defrost…
Full Load Amps
Full Load Amperage (FLA) is the continuous electrical current a…
Fume Hood
A fume hood is a laboratory ventilation device that captures…
Functional Test
A functional test is a procedure verifying individual HVAC components…
Furnace
A furnace is a forced-air heating system that burns fuel…
Furnace Installation
Furnace installation involves mounting a gas or electric heating unit…
Furniture Off Gassing
Furniture off gassing is the release of volatile organic compounds…
Fuse
A fuse is an overcurrent protection device that contains a…