R-454B
R-454B is an A2L refrigerant blend with a GWP of 466 under the AIM Act exchange values[1]. It is the main replacement for R-410A in new residential and light-commercial air conditioners and heat pumps, sold under trade names including Opteon XL41 and Puron Advance.
It sits under the 700 GWP limit for new AC systems (88 FR 73098)[2]. It is mildly flammable (ASHRAE class A2L), which changes handling, tools, and equipment listings compared with R-410A[5].
R-454B quick facts
| Type | A2L blend: 68.9% R-32, 31.1% R-1234yf |
| ASHRAE safety class | A2L (lower flammability) |
| GWP (AIM Act exchange values) | 466 |
| Temperature glide | About 1 to 1.5 °F |
| Lubricant | POE |
| Trade names | Opteon XL41, Puron Advance |
| Common use | New residential and light-commercial AC and heat pumps (R-410A replacement) |
Rules
Federal
The Technology Transitions rule set a 700 GWP limit for new residential and light-commercial AC and heat pump systems, applying to products manufactured from January 1, 2025 (88 FR 73098)[2]. R-410A (GWP 2,088) fails that limit. R-454B and R-32 pass it.
EPA's May 2026 rule (91 FR 31284) removed the installation deadline for systems whose components were manufactured before 2025, so R-410A equipment already built can still be installed[3]. New manufacture belongs to R-454B and R-32.
| Subsector | Limit | Date | R-454B outcome |
|---|---|---|---|
| Residential and light-commercial AC/HP (products) | GWP 700 | Jan 1, 2025 (manufacture)[2] | R-454B compliant |
| Residential and light-commercial AC/HP (installs of pre-2025 components) | install deadline removed | Jul 27, 2026[3] | pre-2025 R-410A equipment installable |
State
California applies a GWP 750 limit to new residential and nonresidential AC from January 1, 2025 under CARB's HFC regulation, and R-454B passes it[6]. Verify with your local authority having jurisdiction. A2L adoption also depends on state building and mechanical codes.
Buying R-454B
Bulk R-454B can only be sold to Section 608-certified technicians and related buyers under 40 CFR 82.154[4]. A2L blends fall under the same sales restriction as the HFCs they replace.
Safety and handling
A2L means lower flammability under ASHRAE Standard 34: harder to ignite and slower-burning than propane-class A3 refrigerants, and not nonflammable like R-410A[5]. Equipment must be designed and listed for A2L use. Use A2L-rated recovery machines and tools. Do not charge R-454B into a system designed for R-410A.
R-454B PT chart
Saturation pressures for R-454B from -40 °F to 130 °F (-40 °C to 54.4 °C), computed from reference equations of state[7]. Operating pressures run close to R-410A, slightly lower. The glide is small (about 1 to 1.5 °F): read the vapor column for superheat and the liquid column for subcooling.
| Temp (°F) | Liquid / bubble (psig) | Vapor / dew (psig) |
|---|---|---|
| -40 | 9.8 | 8.5 |
| -35 | 13.0 | 11.5 |
| -30 | 16.6 | 14.9 |
| -25 | 20.5 | 18.6 |
| -20 | 24.7 | 22.7 |
| -15 | 29.4 | 27.1 |
| -10 | 34.5 | 32.0 |
| -5 | 40.0 | 37.2 |
| 0 | 45.9 | 42.9 |
| 5 | 52.4 | 49.1 |
| 10 | 59.3 | 55.7 |
| 15 | 66.8 | 62.9 |
| 20 | 74.8 | 70.6 |
| 25 | 83.5 | 78.9 |
| 30 | 92.7 | 87.8 |
| 35 | 102.6 | 97.3 |
| 40 | 113.2 | 107.5 |
| 45 | 124.5 | 118.3 |
| 50 | 136.4 | 129.9 |
| 55 | 149.2 | 142.2 |
| 60 | 162.7 | 155.3 |
| 65 | 177.1 | 169.2 |
| 70 | 192.3 | 183.9 |
| 75 | 208.4 | 199.5 |
| 80 | 225.4 | 216.0 |
| 85 | 243.4 | 233.5 |
| 90 | 262.3 | 251.9 |
| 95 | 282.3 | 271.4 |
| 100 | 303.3 | 291.9 |
| 105 | 325.4 | 313.5 |
| 110 | 348.6 | 336.3 |
| 115 | 373.0 | 360.3 |
| 120 | 398.6 | 385.5 |
| 125 | 425.5 | 412.1 |
| 130 | 453.6 | 440.0 |
Use the vapor (dew) column to check superheat at the suction line. Use the liquid (bubble) column to check subcooling at the liquid line and for charging. R-454B has a small glide. Use dew for superheat and bubble for subcooling. R-454B values are computed, not transcribed; see Sources.
Equipment rated for R-454B
R-454B is an air conditioning refrigerant, and no walk-in unit cooler or condensing unit rates it today. The refrigeration A2Ls in the walk-in lines are R-454A, R-454C, and R-455A.
Questions
- Is R-454B flammable?
Mildly. ASHRAE Standard 34 classes it A2L: lower flammability, harder to ignite than A3 refrigerants like propane. Equipment, sensors, and service tools must be rated for A2L use.
- Is R-454B being phased out?
No rule restricts R-454B. It is the replacement refrigerant under the current 700 GWP limit for new AC systems (88 FR 73098). Overall HFC supply follows the AIM Act phasedown, and low-GWP blends consume the fewest allowances per pound.
- What is the difference between R-454B and R-410A?
GWP 466 versus 2,088, and A2L versus A1. Operating pressures are similar, slightly lower for R-454B. The two are not interchangeable: R-454B belongs only in equipment designed and listed for it.
- Can I retrofit an R-410A system to R-454B?
No. R-454B is not approved as a retrofit for R-410A equipment. Flammability listing, sensors, and component ratings differ. Pre-2025 R-410A equipment can still be installed and serviced (91 FR 31284).
References
- ^1.40 CFR part 84, Appendix A: GWP exchange values (eCFR)
- ^2.88 FR 73098 (Oct 24, 2023): Technology Transitions final rule
- ^3.91 FR 31284 (May 26, 2026): Technology Transitions reconsideration final rule
- ^4.40 CFR 82.154: refrigerant sales restriction (eCFR)
- ^5.ASHRAE Standard 34: refrigerant safety classifications
- ^6.CARB HFC reduction program (accessed 2026-08-24)
- ^7.CoolProp 8.0 mixture models (Bell et al. 2014, doi:10.1021/ie4033999)
Updated