A2L Refrigerant Transition Guide
The HVAC and refrigeration industry is transitioning from high-GWP HFC refrigerants to lower-GWP A2L alternatives. Select your current refrigerant below to see the recommended replacements, new detection requirements, and regulatory timelines.
Current: R-410A
Restricted in new residential/light commercial AC equipment as of Jan 1, 2025 (GWP limit: 700)
Recommended A2L Replacements
R-454B
A2LGWP 466Primary replacement in North America. Drop-in not possible — requires new equipment listed to UL 60335-2-40.
Gas Detection Requirements
ASHRAE 15-2022 detection required when charge exceeds RCL (29,000 ppm).
Alarm threshold: 28,750 ppm (25% of LFL at 115,000 ppm)
R-32
A2LGWP 675More common in Asian and European markets. Higher GWP than R-454B but simpler (single-component refrigerant).
Gas Detection Requirements
ASHRAE 15-2022 detection required when charge exceeds RCL (30,000 ppm).
Alarm threshold: 35,250 ppm (25% of LFL at 141,000 ppm)
A2L Refrigerant Safety Data
GWP, RCL, and LFL values from ANSI/ASHRAE Standard 34-2022 and Addendum a
| Refrigerant | Group | GWP | RCL (ppm) | LFL (ppm) | 25% LFL (ppm) | Primary Application |
|---|---|---|---|---|---|---|
| R-32 | A2L | 675 | 30,000 | 141,000 | 35,250 | Residential/commercial AC and heat pumps (Asia, Europe) |
| R-454B | A2L | 466 | 29,000 | 115,000 | 28,750 | Residential/commercial AC and heat pumps (North America) |
| R-454C | A2L | 148 | 29,000 | 77,000 | 19,250 | Medium-temperature commercial refrigeration |
| R-455A | A2L | 148 | 30,000 | 118,000 | 29,500 | Low-temperature commercial refrigeration |
| R-1234yf | A2L | 4 | 30,000 | 62,000 | 15,500 | Automotive AC, chillers |
| R-1234ze(E) | A2L | 6 | 29,000 | 65,000 | 16,250 | Chillers, foam blowing |
Sources: EPA AIM Act, ANSI/ASHRAE 34-2022 & 15-2022, UL 60335-2-40, AHRI Safe Refrigerant Transition Task Force.
Frequently Asked Questions
Related: Refrigeration Monitoring · ASHRAE 15 Guide · Gas Concentration Converter · CET A2L refrigerant detectors
Advisory Disclaimer
This tool is provided for educational and reference purposes only. It summarizes requirements from published standards as of their most recent edition date and does not replace the full text of the applicable standard, local code, or the judgment of a qualified design professional. Values shown here must be verified against the current edition of the relevant standard (ASHRAE 15, ASHRAE 34, IIAR 2, etc.) and the Authority Having Jurisdiction for the project location. Critical Environment Technologies assumes no liability for decisions made using this tool. Always consult a licensed mechanical engineer for system design and compliance determinations.