By Robert Patterson
The short answer: new residential AC and heat pump systems now ship with R-454B, a low-GWP "A2L" refrigerant that replaced R-410A in 2025. It's better for the environment, mildly flammable by classification, and requires an installer trained and certified to handle it.
What changed in 2025?
Under the EPA's AIM Act, the industry moved off R-410A to lower global-warming-potential refrigerants. For most homes that means R-454B, classified as A2L. If you replace your system today, it almost certainly uses it — see our 2025 code-change explainer for how it affects installs.
Why the "A2L" class matters
A2L means mildly flammable — far safer than the gas in your stove, but enough that the equipment, leak detection, and installation practices are different from the R-410A era. That's a reason to use an EPA-certified technician trained on A2L systems.
The failure mode to avoid
The real risk isn't the refrigerant — it's a rushed installer mixing old habits with new equipment. Improper charging or leak handling shortens equipment life. Our TDLR-licensed, EPA-certified technicians install A2L-ready equipment to spec.
What this means when you replace
Keep maintaining your current system. But when it's time for AC replacement, you'll be on R-454B — compare your options with our repair-vs-replace guide, then ask us. More in the Learning Center.