R-454B in a Mini Split: Which System Uses It
Classic AmericaNov 2nd 20263 min read
“R-454B, also sold under trade names like Opteon XL41 and Puron Advance, was developed as a lower-GWP replacement for R-410A in **new** equipment.”
From this article
The short answer
- R-454B is the refrigerant in DUET only (model family MZR454B). The spec sheet lists 1,700 g. DUET is 24 SEER2 non-ducted, with two 9,000 BTU heads, on 208/230V, at $2,065.
- R-454B is about 68.9% R-32 and 31.1% R-1234yf. Its global warming potential is 466, compared with 2,088 for R-410A. Its ASHRAE safety class is A2L, meaning low toxicity and mildly flammable.
- It's not a drop-in replacement for R-410A equipment. Please don't retrofit an older system, and never mix refrigerants.
- Our 9,000 and 19 SEER2 12,000 use R-410A. The 17 SEER2 12,000, the 23,000 BTU model, and both window units use R-32 (GWP 675, also A2L). The 23,000 BTU spec sheet doesn't list a charge weight in grams, so we won't guess one.
What R-454B is
R-454B, also sold under trade names like Opteon XL41 and Puron Advance, was developed as a lower-GWP replacement for R-410A in **new** equipment. Dropping the GWP from 2,088 to 466 is a cut of about 78 percent. The safety class changes too. R-410A is ASHRAE A1 (low toxicity, no flame spread), while R-454B is A2L (low toxicity, mildly flammable). Equipment built for R-454B is designed around that class. An older R-410A machine wasn't.
That's a fact about the equipment, not a service procedure, so you won't find pressures, retrofit charge weights, or cylinder-handling steps here. Anytime the refrigerant circuit is opened, it should be by a licensed HVAC technician. For the policy background, see our California note on R-454B. The table below shows what our catalog actually ships with.
| System | Refrigerant | Note |
|---|---|---|
| DUET | R-454B, 1,700 g | Only R-454B system we sell |
| 9,000 BTU · 23 SEER2 | R-410A, 780 g | Not R-454B |
| 12,000 · 19 SEER2 | R-410A, 970 g | Not R-454B |
| 12,000 class · 17 SEER2 | R-32, 500 g | GWP 675 · A2L |
| 8,000 and 12,000 window | R-32 | Cooling only |
| 23,000 BTU | R-32 | 17 SEER2 · charge weight not listed in grams |
From the spec sheet
- 18,000 BTU/h cooling · 1.5 tons
- 24 SEER2, non-ducted
- 208/230V
- Two 9,000 BTU indoor heads on one outdoor unit
- Heating nameplate 20,000 BTU/h
From the spec sheet
- 11,500 BTU/h cooling · 0.96 tons
- 17 SEER2
- 115V
- Up to 550 sq ft
- Heating nameplate 11,500 BTU/h
Why it is not a refill
R-454B and R-410A are different fluids. The pressures, oil, and safety devices inside the cabinet are designed for one or the other. Putting R-454B into a system built for R-410A isn't a maintenance shortcut. Manufacturers and the safety standards for A2L equipment treat it as a different product, not a top-off. The same goes the other way: DUET should never be charged with R-410A or R-32 just because that cylinder happens to be on the truck. Our 9,000 and 19 SEER2 12,000 systems stay on R-410A for their whole service life, and when they're eventually replaced, the new model uses whatever it was built for.
Refrigerant isn't a homeowner project
- Never vent, mix, or substitute refrigerants.
- Please don't buy a can of R-454B to “upgrade” an R-410A mini split.
- A2L means mildly flammable. That's a safety class for technicians, not an invitation to experiment.
- DIY stops at filters and placement, and opening the refrigerant circuit is a job for a licensed HVAC pro. You're covered for 5 years on the compressor and 1 year on parts.
R-454B means DUET, and only when two rooms need two heads. One room starts at the Size Finder.
Buy the system, not a refrigerant swap
If you want the R-454B system, that's DUET, and it's the right pick when two rooms really do need two heads. If you want a 115V system for a single room, you'll be choosing between R-410A and R-32, and the Size Finder will help you pick the BTU. Our SEER2 versus SEER page covers efficiency. Just remember, none of these choices involve converting a system in the field.
FAQ
Common questions
Which Classic America mini split uses R-454B?
Only DUET. It's our two-zone system: 24 SEER2 non-ducted, 208/230V, listed at $2,065, with a factory charge of 1,700 g of R-454B.
Can I put R-454B in an R-410A mini split?
No. R-454B isn't a drop-in replacement for R-410A. Our 9,000 BTU and 19 SEER2 12,000 BTU systems stay on R-410A.
What is the difference between R-454B and R-32?
R-454B is a blend (about 68.9% R-32 and 31.1% R-1234yf) with a GWP of 466. R-32 is a single fluid with a GWP of 675. Both are ASHRAE A2L, and they aren't interchangeable in our lineup.
What refrigerant is in the 23,000 BTU mini split?
R-32. The current spec sheet doesn't list a charge weight in grams, so we won't make one up. The model is rated 17 SEER2, and it uses neither R-454B nor R-410A.
