The short answer
R-454B is a lower-GWP, mildly flammable (A2L) refrigerant that, with R-32, replaced R-410A in new home AC and heat pump systems. Since January 1, 2025, EPA rules have required a refrigerant with a global warming potential under 700 in a new split system, unless all of its main parts were made or imported before 2025. EPA's May 2026 rule removed the install deadline for that pre-2025 stock, but Washington's own rule still requires a lower-GWP refrigerant in a whole new system installed in Washington since January 1, 2026. If your existing system runs on R-410A, you can keep using and repairing it.
In this guide
What R-454B is, and why the industry switched.
R-454B is a refrigerant blend, about 69% R-32 (a hydrofluorocarbon) and 31% R-1234yf (a hydrofluoroolefin). It replaces R-410A in new home AC and heat pump systems.
The reason for the change is regulatory, not technical. In 2020, Congress passed the American Innovation and Manufacturing (AIM) Act, which directed the EPA to phase down high-global-warming-potential (GWP) refrigerants. EPA's reference table puts R-410A's GWP at 2,088 and R-454B's at 465, roughly 78% lower (R-32's is 675). EPA's 2023 Technology Transitions rule set the limit: from January 1, 2025, a new residential AC or heat pump split system must use a refrigerant with a GWP under 700. EPA notes that U.S. manufacturers already build this equipment with R-32 or R-454B.
The rule has changed twice since. A 2023 interim rule let a split system whose main parts (condensing unit, compressor, evaporator) were all made or imported before January 1, 2025 be installed until January 1, 2026. EPA's final rule of May 2026, effective July 27, 2026, removed that deadline, so leftover pre-2025 R-410A stock can still be installed under federal law. Washington is stricter: the Department of Ecology says that after January 1, 2026, a whole new system installed in the state must use a lower-GWP refrigerant. So a new system installed in Vancouver today runs on R-454B or R-32.
Is R-454B flammable? What the A2L class means.
Yes, mildly: R-454B is classified "A2L" under ASHRAE Standard 34, which means lower toxicity (A) and mildly flammable (2L). The L stands for "lower flammability". ASHRAE's flammability classes run from Class 1 (no flame propagation, where R-410A sits) through 2L and 2 up to Class 3 (higher flammability, where propane, R-290, sits).
In practical terms, EPA lists R-454B for home AC and heat pumps as "acceptable with use conditions": the equipment and the installation have to follow specific safety rules, which is why A2L systems are designed and installed differently from R-410A ones.
The safety work sits with the equipment manufacturer (Mitsubishi Electric, American Standard) and the installing contractor. There is nothing the homeowner needs to do differently.
What this means for cost.
On a quote, R-454B is not a separate line item. The refrigerant is part of the new equipment, and our current installed ranges are in the estimator and the heat pump installation page.
Where refrigerant cost can move is on repairs to older R-410A systems. EPA caps how much HFC refrigerant can be made or imported, at 60% of the baseline from 2024 to 2028 and 30% from 2029 to 2033, and its 2026 rule notes that higher HFC demand may mean tighter supply and higher HFC prices.
If your existing system runs on R-410A.
An existing R-410A system can keep running and be repaired:
- Your system is not illegal. EPA says there are no requirements to stop using equipment already in use, and Washington's Department of Ecology says homeowners can maintain and repair their systems for the life of the equipment.
- Service refrigerant is still available, under a shrinking cap. R-410A can still be made and sold for repairs, under the EPA caps described above.
- You should not "top off" with R-454B. The two refrigerants are not interchangeable. A leak in an R-410A system is repaired with R-410A, and EPA says mildly flammable refrigerants such as R-454B and R-32 cannot be used in systems not designed for them.
- You do not need to upgrade early. If your R-410A system is healthy, run it. When it eventually fails, you will replace it with an R-454B or R-32 system, and you will get the GWP benefit then.
If you are getting bids right now
Any quote for a whole new system in 2026 should name a lower-GWP refrigerant, R-454B or R-32. If a contractor offers "new" R-410A equipment for a whole new system, ask why: federal rules now allow pre-2025 stock, but Washington's rule requires a lower-GWP refrigerant in a whole new system installed since January 1, 2026. We are happy to help interpret a competitive bid if you want a second set of eyes.
The bottom line.
For a homeowner, R-454B mostly changes what is printed on the spec sheet: a whole new system installed in Vancouver, Camas, Battle Ground or elsewhere in Clark County runs on R-454B or R-32, and the American Standard and Mitsubishi Electric equipment we quote uses R-454B. The "mildly flammable" A2L class is handled through equipment design and installation rules, not by the homeowner. Request a quote and we will walk you through exactly what is on the spec sheet, refrigerant included.
Questions homeowners ask.
What is R-454B refrigerant, and why did the HVAC industry switch to it?
R-454B is a refrigerant blend of about 69% R-32 and 31% R-1234yf that, with R-32, replaced R-410A in new home AC and heat pump systems. The switch is regulatory: under the 2020 AIM Act, EPA's 2023 Technology Transitions rule requires a refrigerant with a global warming potential under 700 in a new split system from January 1, 2025. EPA's reference table puts R-410A at 2,088 and R-454B at 465, roughly 78% lower. EPA's May 2026 rule lets pre-2025 R-410A stock still be installed under federal law, but Washington requires a lower-GWP refrigerant in a whole new system installed since January 1, 2026.
Is R-454B refrigerant flammable, and what does A2L mean?
R-454B is classified A2L, meaning lower toxicity (A) and mildly flammable (2L), between non-flammable refrigerants like R-410A (Class 1) and higher-flammability ones like propane. EPA lists R-454B for home AC and heat pumps as acceptable with use conditions, so the equipment and the installation have to follow specific safety rules. That work sits with the manufacturer and the installing contractor; there is nothing the homeowner needs to do differently.
How much more does R-454B add to the cost of a new HVAC install?
On a quote, R-454B is not a separate line item: the refrigerant is part of the new equipment, and our current installed ranges are in the estimator. Where refrigerant cost can move is on repairs to older R-410A systems, because EPA caps how much HFC refrigerant can be made or imported, at 60% of the baseline from 2024 to 2028 and 30% from 2029 to 2033, and its 2026 rule notes that higher HFC demand may mean tighter supply and higher HFC prices.
Is my existing R-410A system still legal to run, and can I still get it serviced?
Yes. EPA says there are no requirements to stop using equipment already in use, and Washington's Department of Ecology says homeowners can maintain and repair their systems for the life of the equipment. R-410A can still be made and sold for repairs, under an EPA cap on HFCs of 60% of the baseline through 2028 and 30% from 2029 to 2033, and EPA's 2026 rule notes that higher HFC demand may mean tighter supply and higher HFC prices. If your R-410A system is healthy, there is no need to upgrade early.
Can an R-410A system be topped off with R-454B refrigerant?
No. The two refrigerants are not interchangeable. A leak in an R-410A system must be repaired using R-410A, and EPA says mildly flammable refrigerants such as R-454B and R-32 cannot be used in systems that were not designed for them, so any technician servicing an older unit should match the original refrigerant.
Sources and resources
Reviewed for accuracy by Sam Tsarenko, founder of Pacific Peak Mechanical. This guide draws on the following primary sources:
- EPA, Technology Transitions HFC Restrictions by Sector, for the 700 GWP limit, the January 1, 2025 date and no install deadline for pre-2025 components
- EPA final rule, Federal Register, May 26, 2026, for the removed deadline, R-32 or R-454B, and possible tighter supply
- Washington Department of Ecology, HFC frequently asked questions, for the January 1, 2026 rule for whole new systems
- EPA, Frequent Questions on the Phasedown of HFCs, for keeping existing equipment, the 60% and 30% caps and no R-454B in systems not designed for it
- EPA, Technology Transitions GWP Reference Table, and EPA SNAP substitutes list, for GWP and the A2L class
Related from Pacific Peak: Equipment we install · AC installation in Vancouver WA
