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R-32 and Low-GWP Central AC Systems

How the EPA AIM Act Technology Transitions rule pushed new central air conditioners to low global-warming-potential refrigerants such as R-32 and R-454B, and what that means for new equipment and existing systems.

New central air conditioners now use next-generation refrigerants with a much lower global warming potential (GWP) than the R-410A that dominated the market for two decades. This shift is driven by the EPA's Technology Transitions rule under the American Innovation and Manufacturing (AIM) Act. This guide explains the GWP limit the rule sets for residential air conditioning, which refrigerants meet it, and what the transition means for equipment buyers and owners of existing systems.

The EPA rule and the 700 GWP limit

The EPA's Technology Transitions rule restricts the global warming potential of refrigerants used in new air conditioning equipment. The EPA states that stationary residential and light commercial air conditioning and heat pumps are subject to a 700 GWP limit, effective January 1, 2025.

The EPA states that the same 700 threshold applies to installed systems in this sector, with a matching compliance date of January 1, 2025. The rule sits under the AIM Act, which directs a broader phasedown of high-GWP hydrofluorocarbon refrigerants.

Which refrigerants meet the new limit

Because R-410A has a GWP of 2,088, it exceeds the 700 limit and cannot be used in new residential systems covered by the rule. Manufacturers have moved to two lower-GWP replacements that fall under the threshold.

The two refrigerants now used in new residential central air conditioners are R-32, with a GWP of 675, and R-454B, with a GWP of 466. Both are classified as mildly flammable A2L refrigerants, which changes some installation and service handling requirements compared with R-410A.

What the transition means for existing systems

The rule targets new equipment, not the systems already installed in homes. The EPA restricts the manufacture and installation of new high-GWP HVAC products beginning January 1, 2025, while systems produced before that date were allowed a window to be installed.

Owners of existing R-410A systems can continue to run and service them, since the phasedown limits new manufacture rather than banning service of legacy equipment. The Department of Energy continues to rate all of this equipment for seasonal cooling efficiency using the SEER2 metric it adopted in 2023.