A2L refrigerants: federal rules and state codes
Why A2Ls are showing up on every job, which rules control them, and where each state stands.
What changed
A2L refrigerants (for example R-454B and R-32) are "lower flammability" refrigerants under the ASHRAE 34 safety classification. Federal HFC limits are moving new comfort-cooling equipment onto them. They can only be installed where the state or local mechanical code allows them.
- Federal (EPA Technology Transitions, 40 CFR 84.54): New residential and light-commercial AC and heat pump systems using HFCs with a GWP of 700 or more can't be installed from Jan 1, 2025. VRF systems had a separate Jan 1, 2026 date. eCFR verified
- May 2026 EPA reconsideration rule: Removes the Jan 1, 2026 installation deadline for over-700-GWP residential and light-commercial systems that were made in or imported into the US before Jan 1, 2025. That pre-2025 inventory can be installed until supply runs out. EPA fact sheet verified
- Model codes: The 2024 I-Codes added A2L provisions, including equipment listed to UL 60335-2-40 and detection, ventilation and charge limits. States on 2021 or older codes need a state amendment, a law, or AHJ approval. ICC verified
- National tracker: AHRI keeps an interactive state-by-state A2L building code map. AHRI A2L map. ACHR News reported in 2026 that A2Ls are now allowed in all 50 states, through codes, interim laws or AHJ approvals. unverified (trade-press report; we haven't checked it state by state)
A2L status by state
| State | A2L status | Check |
|---|---|---|
| Texas | Allowed via 2024 IMC/UMC (TDLR) | verified 2026-10-27 |
| California | Allowed: model-code A2L provisions adopted | verified 2026-10-27 |
| Florida | Allowed: A2L systems designed to ASHRAE 15 | verified 2026-10-29 |
| New York | Allowed: 2025 MCNYS (2024 IMC basis) Chapter 11 | verified 2026-10-29 |
| Ohio | Allowed: 2024 IMC Chapter 11 adopted (effective Oct 15, 2025) | verified 2026-10-27 |
| Indiana | Variance needed: no statewide A2L rule found | unverified 2026-10-29 |
| Pennsylvania | Allowed by state law (Act 123 of 2022) | verified 2026-10-29 |
| Illinois | Allowed by state law; local codes can differ | verified 2026-10-29 |
| Georgia | Allowed: 2024 IMC Chapter 11 adopted | verified 2026-10-29 |
| North Carolina | AHJ approval path under the 2018 NC Mechanical Code | verified 2026-10-29 |
| Michigan | Allowed: 2021 MMC adopts ASHRAE 15-2022 | verified 2026-10-29 |
| New Jersey | Allowed: 2024 IMC adopted (Aug 17, 2026) | verified 2026-10-29 |
| Virginia | Allowed: Virginia amended the 2021 VMC for A2Ls | verified 2026-10-29 |
| Washington | Allowed: SBCC A2L rules for the 2021 IMC (check current rule) | unverified 2026-10-29 |
| Arizona | Allowed: state law bars local refrigerant bans | verified 2026-10-29 |
| Massachusetts | AHJ approval path (BBRS advisory, Nov 12, 2024) | verified 2026-10-29 |
| Tennessee | Allowed by state law (Public Chapter 771 of 2022) | verified 2026-10-29 |
| Colorado | Allowed by state law (HB22-1362) | verified 2026-10-29 |
More states coming. A2L rules change quickly, so confirm with the AHJ before you specify equipment.
Field checklist (general)
- Confirm the adopted mechanical code edition, or the state A2L amendment, for the jurisdiction.
- Check the equipment listing (UL 60335-2-40) and the manufacturer's minimum room area and charge limits.
- Check whether refrigerant detection or mitigation is needed, plus labeling and line-set or shaft requirements.
- Make sure techs are trained on A2L handling and recovery equipment.
General guidance, not a substitute for the adopted code or the AHJ.