R-410A to R-454B: the AC refrigerant transition
In effect, as amended by the May 26, 2026 final rule (effective July 27, 2026).
EPA’s Technology Transitions rule (published October 24, 2023) restricts hydrofluorocarbon refrigerants with a global warming potential of 700 or more, a list that includes R-410A, in new residential and light commercial air conditioning and heat pumps, with a January 1, 2025 compliance date for manufacture and import of self-contained products (January 1, 2026 for VRF systems). A final rule published May 26, 2026 lets inventory of this equipment made in or imported into the US before January 1, 2025 continue to be installed. Existing systems can keep running and be serviced.
What changed for new equipment
New residential AC and heat pumps now use lower-GWP refrigerants. R-454B and R-32 are the replacements the rule’s record discusses for R-410A.
The 2023 rule prohibits the manufacture and import of self-contained residential and light commercial AC and heat pump products using refrigerants with a GWP of 700 or greater from January 1, 2025.
The 2026 change
EPA proposed on October 3, 2025, and finalized on May 26, 2026, changes that include allowing "the inventory of residential and light commercial air conditioning and heat pump equipment that was manufactured in the United States or imported into the United States before January 1, 2025, to continue to be installed."
If your system uses R-410A
Nothing in these rules requires you to replace a working system. Repairs on an existing R-410A system still use R-410A. When the outdoor unit is replaced, mixing an old indoor coil with a new-refrigerant outdoor unit is generally not possible; quotes should say what is being replaced and why.
What to do now
- Look at the outdoor unit’s nameplate for the refrigerant type and add it to My Home.
- On a replacement quote, check the refrigerant named for both the outdoor unit and the indoor coil.
Federal Register documents
- 2023-10-24FR Doc. 2023-22529 · Final rule restricting high-GWP HFCs by sector, including residential AC and heat pumps (Jan 1, 2025).
- 2025-10-03FR Doc. 2025-19438 · Proposed rule reconsidering Technology Transitions requirements, including installation of earlier inventory.
- 2025-11-14FR Doc. 2025-19895 · Comment period extended to November 21, 2025.
- 2026-05-26FR Doc. 2026-10387 · Final rule: pre-2025 residential AC and heat pump inventory may continue to be installed.
A plain-language summary of public documents, not legal or tax advice. Rules in this area have changed several times since 2024; the dates above are the record. Report a change we missed.