R-454B
Near-azeotropic A2L blend of 68.9% R-32 and 31.1% R-1234yf — Carrier's preferred R-410A replacement (marketed as Puron Advance) under the EPA AIM Act 700-GWP threshold.
Lower toxicity. Flame propagates in air at 60°C, but with a low burning velocity (≤ 10 cm/s) and a heat of combustion < 19,000 kJ/kg. Requires A2L-rated equipment, leak detection, and charge limits per UL 60335-2-40 and ASHRAE 15. R-32, R-454B, R-1234yf, R-1234ze(E), R-452B, R-454C, R-455A, R-516A are A2L.
- Flammability
- Low (burning velocity ≤ 10 cm/s)
- Toxicity
- Lower (OEL ≥ 400 ppm)
Classification per ANSI/ASHRAE Standard 34-2022. See full reference.
Saturation pressure-temperature curve
Saturation values from CoolProp 7.2.0 R454B.mix. Operating pressure on a running system differs — see what R-454B operating pressures should be.
R-454B PT chart PDF — printable saturation table
Looking for the R-454B PT chart PDF for shop reference? The complete pressure-temperature saturation table is below — every 1° increment from −40°F to 150°F (or to the refrigerant's critical temperature). Use the Print / Save as PDF button in the table header to download a clean, table-only PDF (the rest of the page is hidden from the print output). Important service temperatures (normal boiling point, freezing point of water, residential AC evap and condenser targets) are tinted and tagged in the table for at-a-glance shop reference.
R-454B PT Chart — Pressure-Temperature Saturation Table
1° increments · Source: CoolProp 7.2.0 / manufacturer datasheet · hvacptcharts.com
| Temp (°F) | Bubble (PSIG) | Dew (PSIG) | Glide (PSI) |
|---|---|---|---|
| -40°F | 9.5 | 8.4 | 1.1 |
| -39°F | 10.1 | 9.0 | 1.2 |
| -38°F | 10.8 | 9.6 | 1.2 |
| -37°F | 11.4 | 10.2 | 1.2 |
| -36°F | 12.1 | 10.8 | 1.3 |
| -35°F | 12.7 | 11.4 | 1.3 |
| -34°F | 13.4 | 12.1 | 1.3 |
| -33°F | 14.1 | 12.8 | 1.3 |
| -32°F | 14.8 | 13.4 | 1.4 |
| -31°F | 15.5 | 14.1 | 1.4 |
| -30°F | 16.2 | 14.8 | 1.4 |
| -29°F | 17.0 | 15.5 | 1.5 |
| -28°F | 17.7 | 16.3 | 1.5 |
| -27°F | 18.5 | 17.0 | 1.5 |
| -26°F | 19.3 | 17.7 | 1.6 |
| -25°F | 20.1 | 18.5 | 1.6 |
| -24°F | 20.9 | 19.3 | 1.6 |
| -23°F | 21.7 | 20.1 | 1.7 |
| -22°F | 22.6 | 20.9 | 1.7 |
| -21°F | 23.4 | 21.7 | 1.7 |
| -20°F | 24.3 | 22.6 | 1.8 |
| -19°F | 25.2 | 23.4 | 1.8 |
| -18°F | 26.1 | 24.3 | 1.8 |
| -17°F | 27.0 | 25.2 | 1.9 |
| -16°F | 28.0 | 26.1 | 1.9 |
| -15°F | 28.9 | 27.0 | 2.0 |
| -14°F | 29.9 | 27.9 | 2.0 |
| -13°F | 30.9 | 28.9 | 2.0 |
| -12°F | 31.9 | 29.8 | 2.1 |
| -11°F | 32.9 | 30.8 | 2.1 |
| -10°F | 33.9 | 31.8 | 2.1 |
| -9°F | 35.0 | 32.8 | 2.2 |
| -8°F | 36.0 | 33.8 | 2.2 |
| -7°F | 37.1 | 34.9 | 2.3 |
| -6°F | 38.3 | 35.9 | 2.3 |
| -5°F | 39.4 | 37.0 | 2.4 |
| -4°F | 40.5 | 38.1 | 2.4 |
| -3°F | 41.7 | 39.2 | 2.5 |
| -2°F | 42.9 | 40.4 | 2.5 |
| -1°F | 44.1 | 41.5 | 2.6 |
| 0°F | 45.3 | 42.7 | 2.6 |
| 1°F | 46.5 | 43.9 | 2.6 |
| 2°F | 47.8 | 45.1 | 2.7 |
| 3°F | 49.0 | 46.3 | 2.7 |
| 4°F | 50.3 | 47.5 | 2.8 |
| 5°F | 51.7 | 48.8 | 2.8 |
| 6°F | 53.0 | 50.1 | 2.9 |
| 7°F | 54.4 | 51.4 | 2.9 |
| 8°F | 55.7 | 52.7 | 3.0 |
| 9°F | 57.1 | 54.1 | 3.0 |
| 10°F | 58.5 | 55.5 | 3.1 |
| 11°F | 60.0 | 56.8 | 3.1 |
| 12°F | 61.5 | 58.2 | 3.2 |
| 13°F | 62.9 | 59.7 | 3.3 |
| 14°F | 64.4 | 61.1 | 3.3 |
| 15°F | 66.0 | 62.6 | 3.4 |
| 16°F | 67.5 | 64.1 | 3.4 |
| 17°F | 69.1 | 65.6 | 3.5 |
| 18°F | 70.7 | 67.1 | 3.5 |
| 19°F | 72.3 | 68.7 | 3.6 |
| 20°F | 73.9 | 70.3 | 3.7 |
| 21°F | 75.6 | 71.9 | 3.7 |
| 22°F | 77.3 | 73.5 | 3.8 |
| 23°F | 79.0 | 75.2 | 3.9 |
| 24°F | 80.7 | 76.8 | 3.9 |
| 25°F | 82.5 | 78.5 | 4.0 |
| 26°F | 84.3 | 80.3 | 4.0 |
| 27°F | 86.1 | 82.0 | 4.1 |
| 28°F | 87.9 | 83.8 | 4.2 |
| 29°F | 89.8 | 85.6 | 4.2 |
| 30°F | 91.7 | 87.4 | 4.3 |
| 31°F | 93.6 | 89.2 | 4.4 |
| 32°FH₂O freeze | 95.5 | 91.1 | 4.4 |
| 33°F | 97.5 | 93.0 | 4.5 |
| 34°F | 99.5 | 94.9 | 4.6 |
| 35°F | 101.5 | 96.9 | 4.6 |
| 36°F | 103.5 | 98.8 | 4.7 |
| 37°F | 105.6 | 100.8 | 4.8 |
| 38°F | 107.7 | 102.8 | 4.8 |
| 39°F | 109.8 | 104.9 | 4.9 |
| 40°FAC evap target | 112.0 | 107.0 | 5.0 |
| 41°F | 114.2 | 109.1 | 5.1 |
| 42°F | 116.3 | 111.2 | 5.1 |
| 43°F | 118.6 | 113.4 | 5.2 |
| 44°F | 120.8 | 115.6 | 5.3 |
| 45°F | 123.1 | 117.8 | 5.3 |
| 46°F | 125.5 | 120.0 | 5.4 |
| 47°F | 127.8 | 122.3 | 5.5 |
| 48°F | 130.2 | 124.6 | 5.6 |
| 49°F | 132.6 | 127.0 | 5.7 |
| 50°F | 135.0 | 129.3 | 5.7 |
| 51°F | 137.5 | 131.7 | 5.8 |
| 52°F | 140.0 | 134.1 | 5.9 |
| 53°F | 142.6 | 136.6 | 6.0 |
| 54°F | 145.1 | 139.1 | 6.0 |
| 55°F | 147.7 | 141.6 | 6.1 |
| 56°F | 150.3 | 144.1 | 6.2 |
| 57°F | 153.0 | 146.7 | 6.3 |
| 58°F | 155.7 | 149.3 | 6.4 |
| 59°F | 158.4 | 151.9 | 6.4 |
| 60°F | 161.1 | 154.6 | 6.5 |
| 61°F | 163.9 | 157.3 | 6.6 |
| 62°F | 166.7 | 160.1 | 6.7 |
| 63°F | 169.6 | 162.8 | 6.8 |
| 64°F | 172.5 | 165.6 | 6.9 |
| 65°F | 175.4 | 168.5 | 6.9 |
| 66°F | 178.3 | 171.3 | 7.0 |
| 67°F | 181.3 | 174.2 | 7.1 |
| 68°F | 184.4 | 177.2 | 7.2 |
| 69°F | 187.4 | 180.1 | 7.3 |
| 70°FRoom T | 190.5 | 183.1 | 7.4 |
| 71°F | 193.6 | 186.2 | 7.4 |
| 72°F | 196.8 | 189.3 | 7.5 |
| 73°F | 200.0 | 192.4 | 7.6 |
| 74°F | 203.2 | 195.5 | 7.7 |
| 75°F | 206.5 | 198.7 | 7.8 |
| 76°F | 209.8 | 201.9 | 7.9 |
| 77°F | 213.1 | 205.2 | 8.0 |
| 78°F | 216.5 | 208.5 | 8.0 |
| 79°F | 219.9 | 211.8 | 8.1 |
| 80°F | 223.4 | 215.2 | 8.2 |
| 81°F | 226.9 | 218.6 | 8.3 |
| 82°F | 230.4 | 222.0 | 8.4 |
| 83°F | 234.0 | 225.5 | 8.5 |
| 84°F | 237.6 | 229.0 | 8.6 |
| 85°F | 241.2 | 232.6 | 8.7 |
| 86°F | 244.9 | 236.2 | 8.7 |
| 87°F | 248.6 | 239.8 | 8.8 |
| 88°F | 252.4 | 243.5 | 8.9 |
| 89°F | 256.2 | 247.2 | 9.0 |
| 90°F | 260.0 | 251.0 | 9.1 |
| 91°F | 263.9 | 254.8 | 9.2 |
| 92°F | 267.9 | 258.6 | 9.3 |
| 93°F | 271.8 | 262.5 | 9.3 |
| 94°F | 275.8 | 266.4 | 9.4 |
| 95°FAHRI design ambient | 279.9 | 270.4 | 9.5 |
| 96°F | 284.0 | 274.4 | 9.6 |
| 97°F | 288.1 | 278.4 | 9.7 |
| 98°F | 292.3 | 282.5 | 9.8 |
| 99°F | 296.5 | 286.7 | 9.8 |
| 100°F | 300.8 | 290.9 | 9.9 |
| 101°F | 305.1 | 295.1 | 10.0 |
| 102°F | 309.4 | 299.4 | 10.1 |
| 103°F | 313.8 | 303.7 | 10.1 |
| 104°F | 318.3 | 308.0 | 10.2 |
| 105°F | 322.8 | 312.4 | 10.3 |
| 106°F | 327.3 | 316.9 | 10.4 |
| 107°F | 331.9 | 321.4 | 10.5 |
| 108°F | 336.5 | 326.0 | 10.5 |
| 109°F | 341.2 | 330.6 | 10.6 |
| 110°FTypical cond saturation | 345.9 | 335.2 | 10.7 |
| 111°F | 350.6 | 339.9 | 10.8 |
| 112°F | 355.4 | 344.6 | 10.8 |
| 113°F | 360.3 | 349.4 | 10.9 |
| 114°F | 365.2 | 354.3 | 11.0 |
| 115°F | 370.2 | 359.1 | 11.0 |
| 116°F | 375.2 | 364.1 | 11.1 |
| 117°F | 380.2 | 369.1 | 11.1 |
| 118°F | 385.3 | 374.1 | 11.2 |
| 119°F | 390.5 | 379.2 | 11.3 |
| 120°F | 395.7 | 384.3 | 11.3 |
| 121°F | 400.9 | 389.5 | 11.4 |
| 122°F | 406.2 | 394.8 | 11.4 |
| 123°F | 411.6 | 400.1 | 11.5 |
| 124°F | 417.0 | 405.4 | 11.5 |
| 125°F | 422.4 | 410.8 | 11.6 |
| 126°F | 427.9 | 416.3 | 11.6 |
| 127°F | 433.5 | 421.8 | 11.7 |
| 128°F | 439.1 | 427.4 | 11.7 |
| 129°F | 444.8 | 433.0 | 11.7 |
| 130°F | 450.5 | 438.7 | 11.8 |
| 131°F | 456.3 | 444.5 | 11.8 |
| 132°F | 462.1 | 450.3 | 11.8 |
| 133°F | 468.0 | 456.1 | 11.8 |
| 134°F | 473.9 | 462.0 | 11.9 |
| Temp (°C) | Bubble (kPa) | Dew (kPa) | Glide (kPa) |
|---|---|---|---|
| -40°C | 66 | 58 | 8 |
| -39°C | 73 | 65 | 8 |
| -38°C | 81 | 73 | 9 |
| -37°C | 90 | 81 | 9 |
| -36°C | 98 | 89 | 9 |
| -35°C | 107 | 97 | 10 |
| -34°C | 116 | 106 | 10 |
| -33°C | 125 | 115 | 10 |
| -32°C | 135 | 124 | 11 |
| -31°C | 145 | 134 | 11 |
| -30°C | 156 | 144 | 12 |
| -29°C | 166 | 154 | 12 |
| -28°C | 177 | 165 | 12 |
| -27°C | 189 | 176 | 13 |
| -26°C | 201 | 187 | 13 |
| -25°C | 213 | 199 | 14 |
| -24°C | 225 | 211 | 14 |
| -23°C | 238 | 223 | 15 |
| -22°C | 252 | 236 | 16 |
| -21°C | 265 | 249 | 16 |
| -20°C | 279 | 263 | 17 |
| -19°C | 294 | 277 | 17 |
| -18°C | 309 | 291 | 18 |
| -17°C | 324 | 306 | 18 |
| -16°C | 340 | 321 | 19 |
| -15°C | 356 | 337 | 20 |
| -14°C | 373 | 353 | 20 |
| -13°C | 390 | 369 | 21 |
| -12°C | 408 | 386 | 21 |
| -11°C | 426 | 404 | 22 |
| -10°C | 444 | 421 | 23 |
| -9°C | 463 | 440 | 24 |
| -8°C | 483 | 459 | 24 |
| -7°C | 503 | 478 | 25 |
| -6°C | 524 | 498 | 26 |
| -5°C | 545 | 518 | 27 |
| -4°C | 566 | 539 | 27 |
| -3°C | 589 | 561 | 28 |
| -2°C | 611 | 583 | 29 |
| -1°C | 635 | 605 | 30 |
| 0°CH₂O freeze | 659 | 628 | 31 |
| 1°C | 683 | 652 | 31 |
| 2°C | 708 | 676 | 32 |
| 3°C | 734 | 701 | 33 |
| 4°CAC evap target | 760 | 726 | 34 |
| 5°C | 787 | 752 | 35 |
| 6°C | 815 | 779 | 36 |
| 7°C | 843 | 806 | 37 |
| 8°C | 872 | 834 | 38 |
| 9°C | 901 | 862 | 39 |
| 10°C | 931 | 892 | 40 |
| 11°C | 962 | 921 | 40 |
| 12°C | 993 | 952 | 41 |
| 13°C | 1,026 | 983 | 42 |
| 14°C | 1,059 | 1,015 | 43 |
| 15°C | 1,092 | 1,048 | 44 |
| 16°C | 1,126 | 1,081 | 45 |
| 17°C | 1,161 | 1,115 | 47 |
| 18°C | 1,197 | 1,150 | 48 |
| 19°C | 1,234 | 1,185 | 49 |
| 20°C | 1,271 | 1,222 | 50 |
| 21°CRoom T | 1,309 | 1,259 | 51 |
| 22°C | 1,348 | 1,296 | 52 |
| 23°C | 1,388 | 1,335 | 53 |
| 24°C | 1,428 | 1,374 | 54 |
| 25°C | 1,470 | 1,415 | 55 |
| 26°C | 1,512 | 1,456 | 56 |
| 27°C | 1,555 | 1,498 | 57 |
| 28°C | 1,598 | 1,540 | 58 |
| 29°C | 1,643 | 1,584 | 59 |
| 30°C | 1,689 | 1,628 | 60 |
| 31°C | 1,735 | 1,674 | 61 |
| 32°C | 1,782 | 1,720 | 62 |
| 33°C | 1,831 | 1,767 | 63 |
| 34°C | 1,880 | 1,815 | 65 |
| 35°CAHRI design ambient | 1,930 | 1,864 | 66 |
| 36°C | 1,981 | 1,914 | 67 |
| 37°C | 2,033 | 1,965 | 68 |
| 38°C | 2,086 | 2,017 | 69 |
| 39°C | 2,140 | 2,070 | 70 |
| 40°C | 2,194 | 2,124 | 71 |
| 41°C | 2,250 | 2,179 | 71 |
| 42°C | 2,307 | 2,235 | 72 |
| 43°CTypical cond saturation | 2,365 | 2,292 | 73 |
| 44°C | 2,424 | 2,350 | 74 |
| 45°C | 2,484 | 2,409 | 75 |
| 46°C | 2,545 | 2,469 | 76 |
| 47°C | 2,608 | 2,531 | 77 |
| 48°C | 2,671 | 2,593 | 77 |
| 49°C | 2,735 | 2,657 | 78 |
| 50°C | 2,801 | 2,722 | 79 |
| 51°C | 2,867 | 2,788 | 79 |
| 52°C | 2,935 | 2,855 | 80 |
| 53°C | 3,004 | 2,924 | 80 |
| 54°C | 3,074 | 2,993 | 81 |
| 55°C | 3,146 | 3,064 | 81 |
| 56°C | 3,218 | 3,137 | 82 |
Full saturation values at 1° increments — toggle between °F / PSIG and °C / kPa. Use Print / Save as PDF for laminated shop reference, or download the CSV / JSON below for use in other tools. R-454B PT chart data: CoolProp 7.2.0 (REFPROP-compatible Helmholtz EOS) or manufacturer datasheet, validated against AHRI Standard 700-2019.
At a glance
Chemistry
Lubricant compatibility
POE required. A2L — mildly flammable. The current leading R-410A replacement in US residential split systems. Similar pressures to R-410A; equipment is rated for A2L handling.
Blend composition
- R-3268.9%
- R-1234yf31.1%
Trade names
- Opteon XL41Chemours
- Puron AdvanceCarrier
Common applications
- Residential central air conditioning (R-410A replacement)
- Heat pumps (residential and light commercial)
- Light commercial split systems
- VRF systems
Properties
- Boiling point (1 atm)-50.5°C / -58.9°F
- Critical pointNo single point — blend critical locus
- Molar mass62.61 g/mol
- Temperature glide2.3°F
- ODP0
- GWP (AR5, 100-yr)466
- GWP (AR6, 100-yr)532
What is R-454B?
R-454B is a near-azeotropic blend of 68.9% R-32 (HFC) and 31.1% R-1234yf (HFO) by mass [ashrae34]. The R-32 component provides capacity and pressure characteristics close to R-410A; the R-1234yf component pulls the blend's overall GWP down to 466 — well below the EPA AIM Act 700-GWP threshold for new residential AC equipment.
The blend is engineered for very small temperature glide (~2°F at typical operating pressures), close enough to azeotropic behavior that most service procedures designed for pure refrigerants apply without adjustment [coolprop]. Carrier markets R-454B as Puron Advance and led its US deployment as the R-410A replacement; Trane and Lennox followed [carrierpuron][trane].
Where R-454B is used
- Residential central AC — new equipment 2025+ (Carrier, Trane, Lennox lead)
- Residential heat pumps
- Light commercial split systems
- Packaged rooftop units (new equipment)
Regulatory & phase-down status
R-454B is among the lowest-GWP blends in the mainstream residential A2L choice set (R-32 at 675, R-454B at 466, R-452B at 698) [ipccar5]. The 466 GWP gives it more regulatory headroom than R-32 — useful as EU F-Gas regulations tighten threshold tiers beyond the current 750-GWP chiller cap.
The EPA AIM Act permits R-454B for new residential AC equipment under the 700-GWP technology transition threshold effective 1 January 2025 [aimact]. SNAP-listed acceptable for residential AC, light commercial AC, and heat pumps [snap].
Service notes
POE oil required — same lubricant family as R-410A and R-32 [ahri700]. Typical viscosity is ISO 32 for residential split systems; OEM-specific viscosity grades apply.
A2L safety class requires nitrogen-purged brazing (standard HFC practice anyway), A2L-rated leak detection, A2L recovery cylinders (yellow with red stripe), and charge limits per UL 60335-2-40 and ASHRAE 15 [ul60335][ashrae15]. Operating pressures track R-410A within ±5%; R-410A-rated 800 PSI service equipment handles R-454B without modification.
Temperature glide
R-454B is a zeotropic blend: at constant pressure it boils across a temperature range rather than at a single point. This affects EXV sizing, charge measurement, and superheat measurement. Use the dew curve for superheat, bubble curve for subcooling.
Operating cycle
Phase-down timeline
No phase-down milestones documented for R-454B in this build. This may mean: (a) no regulatory phase-down currently published; (b) the refrigerant has local regulatory schedules not yet transcribed into the site dataset; or (c) it is a specialty refrigerant outside the main regulatory frameworks. For authoritative current status, consult the EPA AIM Act allocations (40 CFR Part 84), EU F-Gas Regulation 517/2014 + 2024/573, and the relevant national implementations of the Kigali Amendment.
Global warming potential, in context
Residential air conditioning
Retrofit and replacement paths
R-454B replaces
Reading the R-454B pressure-temperature chart
R-454B's PT chart shows two curves at slightly different temperatures because it is a zeotropic blend, but the spread is small — only about 2°F between bubble (saturated liquid) and dew (saturated vapor) at typical operating pressures [coolprop]. Most PT chart presentations show R-454B as a single near-azeotropic curve; the bubble/dew split matters mainly for high-precision charge measurement on systems with strict efficiency requirements.
For routine service measurement, treat R-454B effectively as a pure refrigerant. Superheat at the suction line uses the dew temperature at suction pressure; subcooling at the liquid line uses the bubble temperature at discharge pressure; the ~2°F glide creates a measurement uncertainty that is small relative to typical technician superheat targets of 8-15°F.
Compare R-454B's 2°F glide to R-407C's 11°F or R-454C's 14°F — those zeotropic blends require deliberate dew vs bubble curve selection for accurate superheat math. R-454B's near-azeotropic composition was engineered specifically to deliver R-410A-like service simplicity in a lower-GWP package.
The 68.9 / 31.1 R-32 / R-1234yf composition is deliberate
R-454B combines two refrigerants: 68.9% R-32 (HFC, GWP 675, A2L) and 31.1% R-1234yf (HFO, GWP 4, A2L) by mass [ashrae34]. The composition was engineered against three constraints simultaneously: hit a target GWP below 500, preserve R-410A-comparable capacity, and maintain near-azeotropic behavior for service simplicity.
The math works out cleanly. Mass-weighted GWP = 0.689 × 675 + 0.311 × 4 = 465.9, rounded to 466 [ipccar5]. R-32 dominates the blend's mass and provides most of its volumetric refrigerating capacity; R-1234yf dilutes the GWP without significantly changing pressure envelope or capacity.
A common misconception is that mixing R-32 (A2L) with R-1234yf (A2L) might cancel out the flammability. It doesn't — both components are mildly flammable individually, so the blend is A2L too. This differs from R-410A, where R-125 (A1) was added to R-32 (A2L) specifically to suppress flammability and yield an A1 blend.
Why R-454B operates within ±5% of R-410A
R-454B was deliberately engineered to match R-410A's pressure envelope so equipment design and service procedures could carry over with minimal changes. The R-32-dominant composition (68.9% mass) provides most of the operational characteristics; R-1234yf's slightly lower pressure pulls the blend's overall pressure envelope very slightly below pure R-32 and approximately matches R-410A's.
At a 95°F outdoor design ambient, R-454B saturation is approximately 262 PSIG bubble / 256 PSIG dew, compared to R-410A's effective 278 PSIG (CoolProp 7.2.0). At 70°F bench-test conditions, R-454B bubble is approximately 190 PSIG / dew 184 PSIG, versus R-410A's 202 PSIG. The 5% lower pressure means R-454B equipment can use slightly less robust pressure-rated components than R-410A — though in practice most OEMs use R-410A-rated component designs for inventory and supplier-chain efficiency.
For service technicians, the pressure-envelope match means R-410A-rated 800 PSI manifold gauges, hoses, and recovery cylinders handle R-454B without modification. The only equipment differences from R-410A practice are A2L-specific items: A2L-rated leak detection sensors, yellow-with-red-stripe recovery cylinders, and ignition-source-isolated procedures during service.
GWP 466 — best AIM Act margin among mainstream residential refrigerants
R-454B's GWP of 466 (IPCC AR5, mass-weighted) places it at the low end of the mainstream A2L residential AC refrigerant tier. Compare to alternatives: pure R-32 at 675, R-452B (R-32/R-1234yf 67/33 with R-125) at 698, R-466A at 733 (which exceeds AIM Act). The 234-point margin below the AIM Act 700 threshold gives R-454B substantial regulatory headroom as future threshold tiers may tighten.
The GWP advantage comes from the 31.1% R-1234yf content. R-1234yf is an HFO with very low GWP (4 per IPCC AR5) due to its short atmospheric lifetime (~11 days) — atmospheric chemistry breaks it down rapidly via reactions with OH radicals. Each kilogram of R-1234yf in the R-454B blend displaces R-32 (GWP 675) at the same mass fraction, pulling the total GWP linearly downward.
EU F-Gas Regulation revisions through 2030 may tighten threshold tiers in some segments. R-454B's 466 GWP could comfortably accommodate a 500-GWP threshold; pure R-32 at 675 could not. This is one reason Carrier, Trane, and Lennox chose R-454B over pure R-32 for their residential lines — longer-term regulatory resilience.
ODP zero — both components are fluorine-only
R-454B has zero ozone-depletion potential because neither component contains chlorine [ashrae34]. R-32 (difluoromethane, CH₂F₂) is fluorine-only; R-1234yf (2,3,3,3-tetrafluoropropene, CF₃CF=CH₂) is fluorine-only. The blend inherits the zero-ODP property from both components.
This contrasts with the legacy refrigerants that R-454B replaces. R-22 had ODP 0.055 (small but non-zero, from one chlorine atom per molecule); R-12 had ODP 1.0 (the reference value, from two chlorine atoms); R-502 had ODP 0.221 (from R-115 component). The Montreal Protocol HCFC and CFC phase-outs targeted those refrigerants for their chlorine-driven ozone depletion.
Modern refrigerant policy has shifted from ozone-depletion concerns (largely solved by the Montreal Protocol) to climate concerns (EPA AIM Act, EU F-Gas Regulation, Kigali Amendment). R-454B's regulatory positioning is favorable on both axes: ODP zero (no ozone concern) and GWP 466 (well below current and reasonably-foreseeable GWP thresholds).
Critical point and molar mass — blend property considerations
R-454B is a blend, which means it doesn't have a single critical point — instead it has a critical locus, a curve along which the critical temperature varies with composition. For the 68.9 / 31.1 blend specifically, the critical region is in the neighborhood of 70°C (158°F), which is comfortably above any realistic operating temperature for residential AC equipment.
The mass-weighted molar mass is approximately 62.6 g/mol (0.689 × 52.02 + 0.311 × 114.04). This is heavier than pure R-32 (52 g/mol) due to the R-1234yf addition (heavier 4-atom propene structure with 4 fluorines) but lighter than R-410A's effective 72.6 g/mol average. The resulting volumetric refrigerating capacity is approximately 5% below pure R-32 and approximately 5% above R-410A in equivalent compressor displacement.
For equipment OEMs, this means R-454B systems can use similar compressor displacements to R-410A or R-32 systems with minor recalibration. The blend was designed to fit into existing residential AC equipment architectures without major thermodynamic redesign — which is why the industry transition from R-410A to R-454B was operationally smooth.
Reading the common service temperatures for R-454B
The quick-lookup pills above the PT chart show R-454B saturation pressures at six service-relevant temperatures. Values are reported as bubble / dew where the ~2°F glide is meaningful; for most temperatures the spread is small enough that either reading is usable for typical superheat or subcooling calculations.
- 32°F (freezing) — R-454B saturation approximately 99 PSIG; iced-up evaporator territory.
- 45°F (heat-pump heating) — typical winter outdoor coil temperature when heat pump is heating; R-454B saturation around 135 PSIG.
- 70°F (standard reference) — R-454B saturation 190 PSIG bubble / 184 PSIG dew; bench reference.
- 75°F (test reference) — typical indoor return-air conditions; R-454B saturation around 210 PSIG.
- 80°F (warm-weather operation) — R-454B saturation approximately 222 PSIG.
- 95°F (summer peak) — AHRI 210/240 test condition; R-454B saturation approximately 262 PSIG bubble / 256 PSIG dew.
Compare to R-410A at the same temperatures: R-454B values run 4-6% below R-410A across the residential operating range. This pressure delta is small enough that field service can effectively treat R-454B as R-410A-equivalent for pressure-envelope expectations.
A2L equipment requirements — same as R-32, slightly different from R-410A
R-454B's A2L safety class requires the same equipment-level safety design as pure R-32 — sealed motors, charge limits per ASHRAE 15, A2L-rated leak detection in some installations, and ignition-source isolation per UL 60335-2-40 [ul60335][ashrae15]. From a service-tool perspective, R-454B and R-32 are essentially interchangeable: same pressure ratings, same lubricant family, same A2L procedures.
| Equipment / procedure | R-410A (A1) | R-454B (A2L) | | --- | --- | --- | | Manifold gauge rating | 800 PSI | 800 PSI | | Recovery cylinder | Pink, 600 PSI service | Yellow with red top stripe (A2L marker) | | Compressor motor | Standard hermetic | Sealed motor in refrigerant circuit per UL 60335-2-40 | | Charge limits | None (A1) | Scaled to smallest enclosed space per ASHRAE 15 | | Leak detection | Optional | Required in some installations per UL 60335-2-40 | | Brazing during service | Nitrogen purge standard | Nitrogen purge mandatory; no open flames near system | | Lubricant | POE | POE (same family) | | Vacuum target | 500 microns held 30+ min | 500 microns held 30+ min | | Service port type | 5/16" SAE | 5/16" SAE (same) |
The transition from R-410A service practice to R-454B service is primarily about A2L procedures. Pressure ratings, lubricant chemistry, vacuum discipline, and service ports all carry over. Distributor and OEM training programs typically cover R-32 and R-454B together in 1-2 day A2L familiarization courses.
POE oil — identical chemistry to R-410A and R-32 systems
R-454B requires polyolester (POE) oil, the same synthetic lubricant family used with R-410A and R-32 [ahri700]. Typical residential R-454B systems use ISO 32 viscosity POE; commercial applications may use ISO 22 or ISO 46. The viscosity grade is specified by the equipment OEM and reflects the compressor design — verify against equipment service literature before adding oil.
POE oil's compatibility with R-454B (and with HFC/HFO refrigerants generally) derives from its polar ester groups, which mix with the polar refrigerant molecules and return reliably through the compressor in the refrigerant flow. Mineral oil and alkylbenzene (used with R-22 and earlier HCFC/CFC refrigerants) are not miscible and would not return — never mix oil chemistries across the HCFC/HFC boundary.
POE oil is hygroscopic: it absorbs atmospheric moisture rapidly when exposed to air. Moisture in a sealed refrigeration system reacts with POE to form weak organic acids that corrode metal surfaces and degrade lubrication. The standard defense is rigorous vacuum: 500 microns held for at least 30 minutes before opening the system to refrigerant. A failing vacuum hold indicates a leak or residual moisture that must be resolved before charging.
OEM choice — Carrier / Trane / Lennox vs Daikin / Mitsubishi / LG
The 2024-2025 US residential AC industry transition from R-410A to A2L refrigerants split the major OEMs into two camps. Carrier, Trane (Ingersoll Rand / Trane Technologies), and Lennox standardized on R-454B, marketed under Carrier's "Puron Advance" brand and equivalent OEM branding elsewhere [carrierpuron][trane]. Daikin Industries, Mitsubishi Electric, LG, and Fujitsu standardized on pure R-32 — leveraging Daikin's commercial R-32 deployment experience dating back to 2012.
The OEM split reflects strategic choices rather than technical superiority. Pure R-32 offers slightly higher capacity and simpler chemistry but higher GWP (675 vs 466) and slightly higher discharge temperature. R-454B offers lower GWP and discharge temperature but adds the complexity of a blend (small glide, fractionation concern during partial charging). Daikin's R-32 patent portfolio gave the company a manufacturing-cost advantage; the R-454B camp pursued an independent technology path.
For homeowners and contractors, the choice between R-32 and R-454B is typically determined by equipment brand availability rather than refrigerant preference. Both refrigerants will be commercially serviceable through the 2030s; both clear the AIM Act 700-GWP threshold; both use POE oil and require A2L service procedures.
How to think about R-454B in 2026 and beyond
R-454B is one of two dominant new-equipment residential AC refrigerants in 2026, alongside pure R-32. The Carrier / Trane / Lennox standardization gives R-454B substantial US market share — likely 50-60% of new residential AC installations through the late 2020s, with R-32 capturing the balance through Daikin / Mitsubishi / LG / Fujitsu sales.
R-454B's GWP 466 provides the best regulatory headroom in the mainstream A2L tier. As future EU F-Gas thresholds may tighten beyond the current 750-GWP chiller cap and US AIM Act may add new technology transitions, R-454B's lower baseline gives the chemistry a longer regulatory runway than pure R-32. EU F-Gas Regulation revisions in 2024 already target tighter thresholds in some segments through 2030.
For technicians, R-454B work resembles R-32 work — A2L procedures, POE oil, ~800 PSI service equipment, near-azeotropic behavior. The small (~2°F) glide is operationally negligible compared to true zeotropic blends; field service can effectively treat R-454B as a pure refrigerant for routine superheat and subcooling measurement. R-454B-specific training is typically bundled with R-32 in distributor and OEM training courses.
Frequently asked
›What is the normal operating pressure of R-454B?
Very close to R-410A — generally within ±5% across the operating envelope. At 95°F outdoor, expect roughly 130 PSIG suction and 350-390 PSIG discharge on a properly-charged residential R-454B system. R-454B saturation at 95°F is approximately 262 PSIG bubble / 256 PSIG dew (CoolProp 7.2.0).
›What does R-454B's GWP of 466 mean?
Global Warming Potential is a relative atmospheric-warming metric over 100 years against CO₂ (defined as GWP 1). A 1 kg release of R-454B traps approximately 466 times more heat than 1 kg of CO₂ over that horizon (IPCC AR5, mass-weighted from 68.9% R-32 × 675 + 31.1% R-1234yf × 4) [ipccar5].
The figure places R-454B well below the EPA AIM Act 700-GWP threshold for residential AC and approximately 33% below R-32 (675). It gives R-454B more regulatory headroom than R-32 as future thresholds tighten.
›What's the difference between R-454B and R-32?
Both are A2L refrigerants for residential AC. R-32 is pure (no glide), GWP 675, preferred by Daikin / Mitsubishi / LG / Fujitsu. R-454B is a blend (68.9% R-32 + 31.1% R-1234yf), GWP 466, ~2°F glide, preferred by Carrier / Trane / Lennox [carrierpuron][trane].
Performance is comparable. R-454B's slightly lower GWP comes from the R-1234yf component; the small glide is the trade-off. Equipment availability in your market typically determines the choice.
›Is R-454B safe to handle?
R-454B is ASHRAE class A2L, mildly flammable with low burning velocity. A2L equipment design (sealed motors, leak detection, charge limits, ignition-source isolation per UL 60335-2-40) mitigates the flammability risk to acceptable levels for residential applications [ul60335].
R-454B has been deployed extensively in US residential AC since 2024 with a strong safety record. For technicians: A2L procedures (no open flames near refrigerant, A2L-rated leak detection, nitrogen-purged brazing) apply; treating R-454B as if it were A1 R-410A is a safety-critical error.
›Does R-454B have temperature glide?
Yes, approximately 2°F at typical operating pressures (CoolProp 7.2.0). This is very small compared to R-407C's 11°F or R-454C's 14°F — the 68.9/31.1 composition is specifically engineered for near-azeotropic behavior.
For practical service measurement, R-454B can be treated like a near-azeotrope: the dew/bubble curve distinction for superheat and subcooling matters less than for true zeotropic blends. The site's calculators handle the small glide automatically.
›What is Puron Advance?
Puron Advance is Carrier's trade name for R-454B [carrierpuron]. Carrier's original "Puron" brand was applied to R-410A starting in 1996; "Puron Advance" extends the brand to the AIM Act-compliant R-454B replacement.
Trane and Lennox market R-454B equipment without the Puron branding but with similar positioning. Honeywell supplies the refrigerant as Solstice 454B; Chemours supplies it as Opteon XL41 [honeywellsolstice][chemoursopteon].
›Can I retrofit an R-410A system to R-454B?
No, not safely. R-410A equipment is A1-rated (no flammability accommodations); R-454B is A2L and requires sealed motors and A2L-rated safety design per UL 60335-2-40. Retrofitting an A1-rated chassis to an A2L refrigerant is not authorized by OEMs and is non-compliant with code in most jurisdictions [ul60335].
For R-410A equipment needing replacement, new R-454B or R-32 systems are the path forward.
›What lubricant does R-454B use?
Polyolester (POE) oil — the same lubricant family used with R-410A and R-32 [ahri700]. Typical viscosity is ISO 32 for residential split systems; verify against equipment OEM spec for commercial applications.
POE is hygroscopic — pull vacuum to 500 microns and hold ≥30 minutes before charging.
Sources & citations
- [1]ASHRAE Standard 34-2022 — Designation and Safety Classification of Refrigerants
- [2]IPCC AR5 (2014) Working Group I, Chapter 8, Table 8.A.1
- [3]EPA AIM Act — 40 CFR Part 84 Subpart B + Technology Transitions RuleFinal Rule Oct 2021, Technology Transitions Rule Oct 2023https://www.epa.gov/climate-hfcs-reduction
- [4]EPA Significant New Alternatives Policy (SNAP) — R-454B acceptable for residential AC
- [5]UL 60335-2-40 / IEC 60335-2-40 — Safety standard for AC equipment using A2L refrigerants
- [6]ASHRAE Standard 15-2022 — A2L charge limits for refrigeration systems
- [7]CoolProp 7.2.0 (Bell, Wronski, Quoilin, Lemort 2014) — REFPROP-compatible Helmholtz EOS
- [8]AHRI Standard 700-2019 — Specifications for Refrigerants
- [9]Honeywell Solstice 454B (R-454B) Technical Information
- [10]Chemours Opteon XL41 (R-454B) Product Data Sheet
- [11]Carrier Puron Advance — R-454B brand documentation
- [12]Trane R-454B equipment service documentation