R-454B and R-32: the refrigerant change.

By Tyler Wayne, FMP · Working B2B HVAC Rep on the Wasatch Front · Updated October 2026

Under the EPA's AIM Act rules, new air conditioning and heat pump equipment of the size most commercial rooftop units and split systems fall into now uses lower impact refrigerants such as R-454B and R-32 instead of R-410A. Your existing R-410A equipment can keep running and be serviced. The change matters when you replace equipment.

A new rooftop unit lifted by crane onto a roof curb

What changed

The EPA's Technology Transitions rule limits the global warming potential of refrigerants in new equipment. For residential and light commercial air conditioning and heat pumps, new systems manufactured from January 1, 2025 had to use refrigerants below the limit, with a later installation deadline for some split system parts built before then. Other equipment types, like chillers, have their own dates. The EPA's Technology Transitions page has the details.

What it means for buildings you already run

Existing R-410A units can stay in service and be repaired.
You can't put R-454B or R-32 into an R-410A system. They're different refrigerants with different equipment.
When an R-410A unit fails for good, its replacement will most likely use one of the new refrigerants.

What's different about the new refrigerants

R-454B and R-32 are classed as A2L, meaning mildly flammable. Equipment built for them follows updated safety standards and some include refrigerant leak detection. Technicians need training on A2L handling. Ask your service provider whether their techs are trained before they work on new units.

Planning a replacement

Ask which refrigerant the new unit uses and whether your service provider supports it.
Check the curb, electrical and controls fit before ordering.
Plan around lead times so you aren't replacing in the middle of a heat wave.

Weighing whether to replace at all? Start with repair or replace a 15 year old rooftop unit.

Common questions

Do I have to replace my R-410A units?

No. Existing R-410A equipment can keep running and be serviced. The rules apply to new equipment.

Can an R-410A unit be converted to R-454B?

Generally no. The new refrigerants need equipment designed and listed for them.

Are A2L refrigerants safe?

They are mildly flammable and used in equipment built to updated safety standards, often with leak detection. Trained technicians matter more than ever.