2,400+ Definitions
HVAC GLOSSARY
Every HVAC term, acronym, and industry phrase — defined in plain English.
Outside Air Damper
An outside air damper is a motorized or gravity-operated device…
Overall U-Factor
The area-weighted average thermal transmittance of an entire fenestration unit…
Overcharge
An overcharge occurs when excess refrigerant is added to a…
Oxy-Acetylene Torch
A high-temperature cutting and welding torch that burns a mixture…
Oxygen Barrier Tubing
PEX or other flexible tubing with an added layer, typically…
Ozone Generator
Ozone generators produce ozone gas (O₃) that oxidizes odors, VOCs,…