The short answer
R-454B and R-32 are the two main refrigerants in new US air conditioners and heat pumps. Both meet EPA’s 700 GWP limit for new residential systems.
R-32 is a single compound with a GWP of 675 on EPA’s table; R-454B blends R-32 with a low-GWP HFO, which brings its GWP down to around 466.
Both are classed A2L, mildly flammable, and neither can go into a system built for the other or for R-410A.
Why did the industry switch?
Under the AIM Act, EPA’s Technology Transitions rule caps the global warming potential of refrigerants in new residential and light commercial AC and heat pump systems at 700. R-410A, with a GWP of 2,088 on EPA’s reference table, is far above it. Manufacturers split between two replacements: R-454B and R-32.
Existing R-410A systems can keep running and be serviced. The rules govern new equipment, not what is already installed.
R-454B vs R-32 at a glance
| R-454B | R-32 | |
|---|---|---|
| What it is | Blend of R-32 and R-1234yf (an HFO) | Single compound, difluoromethane |
| GWP | About 466 (manufacturer data, AR4 basis) | 675 (EPA reference table) |
| Safety class | A2L, mildly flammable | A2L, mildly flammable |
| Blend behavior | Slight temperature glide; charge as liquid | No glide |
| Under the 700 limit | Yes | Yes |
| Drop-in for R-410A | No | No |
EPA GWP reference table and EPA Technology Transitions page, checked October 26, 2026.
Does it matter which one your system uses?
For performance, not much you can feel. Each manufacturer designed its equipment around the refrigerant it chose, and the efficiency you get is shown in the AHRI rating for the matched system, not in the refrigerant name. Compare SEER2 and HSPF2 for the exact pairing.
It matters for service. A technician must use the correct refrigerant, tools rated for A2L gases and the procedures in the manufacturer’s instructions. Mixing refrigerants, or topping up one with the other, is not allowed and damages the system.
What drives the cost of an install is the equipment, the indoor coil match, line-set work and labor, not which of the two refrigerants is inside.
We publish no prices here: we do not yet hold enough sourced, dated quotes to state one honestly. Use the cost hub and the HVAC cost calculator with your own quotes.
What owners should know about A2L refrigerants
A2L refrigerants need a larger concentration and a strong ignition source to burn. Systems are built with leak detection or charge limits as the standards require.
EPA Section 608 certification is required for anyone who opens the refrigerant circuit or attaches gauges.
If a system needs refrigerant, it has a leak. The leak should be found and fixed first.
A new R-454B or R-32 outdoor unit needs an indoor coil rated for that refrigerant.
What happens to service on older R-410A systems?
Nothing changes overnight. Existing R-410A systems can still be repaired and recharged by certified technicians using R-410A. Over time, as supply shifts, some owners may weigh a repair on an old system against replacing it.
That is a normal repair-or-replace decision, and the refrigerant is one factor among several: the age of the system, the size of the repair, the condition of the indoor coil and line set, and the efficiency you would gain. Our repair or replace calculator helps structure it.
If you replace only the outdoor unit, the indoor coil must also be compatible with the new refrigerant. A new R-454B or R-32 outdoor unit paired with an old R-410A coil is not an approved match. Ask the installer for the AHRI reference that shows the exact pairing.
Where does each one win?
R-454B wins on GWP: its number is lower. R-32 wins on simplicity: a single compound with no temperature glide, which can make recovery and recharging more straightforward, and it is widely used in mini splits worldwide. Neither is a reason on its own to choose one brand over another.
Questions
Is R-454B better than R-32?
Can R-454B replace R-410A in my old system?
Are these refrigerants dangerous?
Do I have to replace my R-410A system?
Who can charge an R-32 or R-454B system?
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