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
R Value
R Value measures the thermal resistance of insulation materials, indicating…
R-11
R-11, also known as Trichlorofluoromethane, is a chlorofluorocarbon (CFC) refrigerant…
R-12
R-12, also known as dichlorodifluoromethane, is a chlorofluorocarbon (CFC) refrigerant…
R-123
R-123, chemically known as 2,2-dichloro-1,1,1-trifluoroethane (CHCl₂CF₃), is a hydrochlorofluorocarbon (HCFC)…
R-1234yf
R-1234yf is a hydrofluoroolefin (HFO) refrigerant with an exceptionally low…
R-1234ze
R-1234ze is a hydrofluoroolefin (HFO) refrigerant with a GWP of…
R-124
R-124, also known as chlorotetrafluoroethane (chemical formula C₂HClF₄), is a…
R-125
R-125, also known as pentafluoroethane, is a hydrofluorocarbon (HFC) refrigerant…
R-1336mzz
R-1336mzz is a hydrofluoroolefin (HFO) refrigerant with the chemical formula…
R-134a
R-134a is a hydrofluorocarbon (HFC) refrigerant with zero ozone depletion…
R-152a
R-152a (1,1-Difluoroethane) is a hydrofluorocarbon (HFC) refrigerant with the chemical…
R-22
R-22, also known as chlorodifluoromethane, is a chlorofluorocarbon (CFC) refrigerant…
R-245fa
R-245fa (1,1,1,3,3-pentafluoropropane) is a hydrofluorocarbon (HFC) refrigerant with the chemical…
R-290
R-290 is a refrigerant-grade propane (C₃H₈) with a minimum purity…
R-32
R-32 is a hydrofluorocarbon (HFC) refrigerant with zero ozone depletion…
R-404A
R-404A is a hydrofluorocarbon (HFC) blend refrigerant composed of three…
R-407A
R-407A is a non-ozone depleting hydrofluorocarbon (HFC) refrigerant blend consisting…
R-407C
R-407C is a hydrofluorocarbon (HFC) blend refrigerant designed as a…
R-407F
R-407F is a zeotropic hydrofluorocarbon (HFC) refrigerant blend composed of…
R-408A
R-408A is a zeotropic refrigerant blend composed of R-22 (47%),…
R-409A
R-409A is a hydrochlorofluorocarbon (HCFC)-based refrigerant blend developed as a…
R-410A
R-410A is a hydrofluorocarbon (HFC) refrigerant that became the standard…
R-417A
R-417A is a non-ozone depleting hydrofluorocarbon (HFC) blend refrigerant composed…
R-421A
R-421A is a zeotropic blend refrigerant composed of 59% R-134a,…
R-422B
R-422B is a hydrofluorocarbon (HFC) refrigerant blend composed of R-125…
R-422D
R-422D is a non-ozone-depleting hydrofluorocarbon (HFC) refrigerant blend developed as…
R-427A
R-427A, commonly marketed under the trade name Forane 427A or…
R-434A
R-434A is a hydrofluorocarbon/hydrofluoro-olefin (HFC/HFO) blend refrigerant developed as a…
R-438A
R-438A, commercially known as MO99, is a hydrofluorocarbon (HFC) blend…
R-448A
R-448A is a low-global-warming-potential (GWP) hydrofluoroolefin (HFO) blend refrigerant designed…
R-449A
R-449A is a non-flammable HFO-based refrigerant blend designed as a…
R-450A
R-450A is a non-ozone depleting hydrofluoro-olefin (HFO) blend refrigerant marketed…
R-452A
R-452A is a hydrofluoroolefin (HFO)-based refrigerant blend designed as a…
R-452B
R-452B is a low-GWP replacement refrigerant for R-410A and R-32…
R-454A
R-454A is a non-ozone depleting, low-GWP hydrofluoroolefin (HFO) blend refrigerant…
R-454B
R-454B (brand name Opteon XL41, manufactured by Chemours) is the…
R-454C
R-454C is a near-azeotropic HFO refrigerant blend with a GWP…
R-455A
R-455A, marketed under the trade name Solstice® LBA, is a…
R-466A
R-466A is a non-flammable, zeotropic refrigerant blend developed as a…
R-470A
R-470A is a zeotropic, non-ozone depleting refrigerant blend composed of…
R-513A
R-513A is a non-ozone depleting, HFO-based refrigerant blend consisting of…
R-515B
R-515B is a hydrofluoroolefin (HFO) refrigerant blend composed of R-1234ze(E)…
R-600a
R-600a, also known as isobutane, is a natural hydrocarbon (HC)…
R-717
R-717, also known as ammonia (NH3), is a natural refrigerant…
R-744
R-744, commonly known as carbon dioxide (CO2), is a natural…
Radiant Ceiling Panel
A radiant ceiling panel is a heating and cooling system…
Radiant Floor Heating
Radiant floor heating (RFH) is a space-heating method that employs…
Radiant Panel
A radiant panel is a heat transfer device engineered to…