R-407C
Ternary HFC blend (R-32/R-125/R-134a 23/25/52 mass) — A1 safety, GWP 1774, ~11°F temperature glide. The most-deployed R-22 retrofit refrigerant since the early 2000s.
Lower toxicity (Occupational Exposure Limit ≥ 400 ppm). No flame propagation in air at standard atmospheric pressure and 60°C. R-134a, R-22, R-410A, R-404A, R-744 (CO2) are A1.
- Flammability
- None (no flame propagation)
- 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 R407C.mix. Operating pressure on a running system differs — see what R-407C operating pressures should be.
R-407C PT chart PDF — printable saturation table
Looking for the R-407C 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-407C 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 | 2.8 | -2.3 | 5.0 |
| -39°F | 3.2 | -1.9 | 5.1 |
| -38°F | 3.7 | -1.6 | 5.2 |
| -37°F | 4.1 | -1.2 | 5.3 |
| -36°F | 4.6 | -0.8 | 5.4 |
| -35°F | 5.1 | -0.4 | 5.5 |
| -34°F | 5.6 | -0.0 | 5.6 |
| -33°F | 6.1 | 0.4 | 5.7 |
| -32°F | 6.7 | 0.8 | 5.9 |
| -31°F | 7.2 | 1.2 | 6.0 |
| -30°F | 7.7 | 1.6 | 6.1 |
| -29°F | 8.3 | 2.1 | 6.2 |
| -28°F | 8.8 | 2.5 | 6.3 |
| -27°F | 9.4 | 3.0 | 6.4 |
| -26°F | 10.0 | 3.5 | 6.5 |
| -25°F | 10.6 | 3.9 | 6.7 |
| -24°F | 11.2 | 4.4 | 6.8 |
| -23°F | 11.8 | 4.9 | 6.9 |
| -22°F | 12.4 | 5.4 | 7.0 |
| -21°F | 13.1 | 5.9 | 7.1 |
| -20°F | 13.7 | 6.5 | 7.3 |
| -19°F | 14.4 | 7.0 | 7.4 |
| -18°F | 15.1 | 7.5 | 7.5 |
| -17°F | 15.8 | 8.1 | 7.7 |
| -16°F | 16.5 | 8.7 | 7.8 |
| -15°F | 17.2 | 9.3 | 7.9 |
| -14°F | 17.9 | 9.9 | 8.1 |
| -13°F | 18.6 | 10.5 | 8.2 |
| -12°F | 19.4 | 11.1 | 8.3 |
| -11°F | 20.2 | 11.7 | 8.5 |
| -10°F | 20.9 | 12.3 | 8.6 |
| -9°F | 21.7 | 13.0 | 8.7 |
| -8°F | 22.5 | 13.7 | 8.9 |
| -7°F | 23.4 | 14.3 | 9.0 |
| -6°F | 24.2 | 15.0 | 9.2 |
| -5°F | 25.0 | 15.7 | 9.3 |
| -4°F | 25.9 | 16.4 | 9.5 |
| -3°F | 26.8 | 17.2 | 9.6 |
| -2°F | 27.7 | 17.9 | 9.8 |
| -1°F | 28.6 | 18.7 | 9.9 |
| 0°F | 29.5 | 19.4 | 10.1 |
| 1°F | 30.4 | 20.2 | 10.2 |
| 2°F | 31.4 | 21.0 | 10.4 |
| 3°F | 32.3 | 21.8 | 10.5 |
| 4°F | 33.3 | 22.6 | 10.7 |
| 5°F | 34.3 | 23.5 | 10.8 |
| 6°F | 35.3 | 24.3 | 11.0 |
| 7°F | 36.4 | 25.2 | 11.2 |
| 8°F | 37.4 | 26.1 | 11.3 |
| 9°F | 38.5 | 27.0 | 11.5 |
| 10°F | 39.5 | 27.9 | 11.7 |
| 11°F | 40.6 | 28.8 | 11.8 |
| 12°F | 41.7 | 29.8 | 12.0 |
| 13°F | 42.9 | 30.7 | 12.1 |
| 14°F | 44.0 | 31.7 | 12.3 |
| 15°F | 45.2 | 32.7 | 12.5 |
| 16°F | 46.3 | 33.7 | 12.6 |
| 17°F | 47.5 | 34.7 | 12.8 |
| 18°F | 48.7 | 35.7 | 13.0 |
| 19°F | 50.0 | 36.8 | 13.2 |
| 20°F | 51.2 | 37.9 | 13.4 |
| 21°F | 52.5 | 39.0 | 13.5 |
| 22°F | 53.8 | 40.1 | 13.7 |
| 23°F | 55.1 | 41.2 | 13.9 |
| 24°F | 56.4 | 42.3 | 14.1 |
| 25°F | 57.7 | 43.5 | 14.3 |
| 26°F | 59.1 | 44.7 | 14.4 |
| 27°F | 60.5 | 45.9 | 14.6 |
| 28°F | 61.9 | 47.1 | 14.8 |
| 29°F | 63.3 | 48.3 | 15.0 |
| 30°F | 64.7 | 49.6 | 15.2 |
| 31°F | 66.2 | 50.8 | 15.3 |
| 32°FH₂O freeze | 67.7 | 52.1 | 15.6 |
| 33°F | 69.2 | 53.4 | 15.7 |
| 34°F | 70.7 | 54.8 | 15.9 |
| 35°F | 72.2 | 56.1 | 16.1 |
| 36°F | 73.8 | 57.5 | 16.3 |
| 37°F | 75.4 | 58.9 | 16.5 |
| 38°F | 77.0 | 60.3 | 16.7 |
| 39°F | 78.6 | 61.7 | 16.9 |
| 40°FAC evap target | 80.2 | 63.2 | 17.1 |
| 41°F | 81.9 | 64.6 | 17.3 |
| 42°F | 83.6 | 66.1 | 17.5 |
| 43°F | 85.3 | 67.6 | 17.7 |
| 44°F | 87.0 | 69.2 | 17.9 |
| 45°F | 88.8 | 70.7 | 18.1 |
| 46°F | 90.6 | 72.3 | 18.3 |
| 47°F | 92.4 | 73.9 | 18.5 |
| 48°F | 94.2 | 75.5 | 18.7 |
| 49°F | 96.0 | 77.2 | 18.9 |
| 50°F | 97.9 | 78.8 | 19.1 |
| 51°F | 99.8 | 80.5 | 19.3 |
| 52°F | 101.7 | 82.2 | 19.5 |
| 53°F | 103.7 | 84.0 | 19.7 |
| 54°F | 105.6 | 85.7 | 19.9 |
| 55°F | 107.6 | 87.5 | 20.1 |
| 56°F | 109.6 | 89.3 | 20.3 |
| 57°F | 111.7 | 91.2 | 20.5 |
| 58°F | 113.7 | 93.0 | 20.7 |
| 59°F | 115.8 | 94.9 | 20.9 |
| 60°F | 118.0 | 96.8 | 21.1 |
| 61°F | 120.1 | 98.7 | 21.4 |
| 62°F | 122.3 | 100.7 | 21.5 |
| 63°F | 124.4 | 102.7 | 21.8 |
| 64°F | 126.7 | 104.7 | 22.0 |
| 65°F | 128.9 | 106.7 | 22.2 |
| 66°F | 131.2 | 108.8 | 22.4 |
| 67°F | 133.5 | 110.9 | 22.6 |
| 68°F | 135.8 | 113.0 | 22.8 |
| 69°F | 138.2 | 115.1 | 23.0 |
| 70°FRoom T | 140.5 | 117.3 | 23.2 |
| 71°F | 142.9 | 119.5 | 23.4 |
| 72°F | 145.4 | 121.7 | 23.7 |
| 73°F | 147.8 | 124.0 | 23.9 |
| 74°F | 150.3 | 126.2 | 24.1 |
| 75°F | 152.8 | 128.6 | 24.3 |
| 76°F | 155.4 | 130.9 | 24.5 |
| 77°F | 157.9 | 133.3 | 24.7 |
| 78°F | 160.6 | 135.6 | 24.9 |
| 79°F | 163.2 | 138.1 | 25.1 |
| 80°F | 165.8 | 140.5 | 25.3 |
| 81°F | 168.5 | 143.0 | 25.5 |
| 82°F | 171.3 | 145.5 | 25.8 |
| 83°F | 174.0 | 148.1 | 25.9 |
| 84°F | 176.8 | 150.6 | 26.2 |
| 85°F | 179.6 | 153.2 | 26.4 |
| 86°F | 182.4 | 155.8 | 26.6 |
| 87°F | 185.3 | 158.5 | 26.8 |
| 88°F | 188.2 | 161.2 | 27.0 |
| 89°F | 191.1 | 163.9 | 27.2 |
| 90°F | 194.1 | 166.7 | 27.4 |
| 91°F | 197.1 | 169.5 | 27.6 |
| 92°F | 200.1 | 172.3 | 27.8 |
| 93°F | 203.2 | 175.2 | 28.0 |
| 94°F | 206.3 | 178.1 | 28.2 |
| 95°FAHRI design ambient | 209.4 | 181.0 | 28.4 |
| 96°F | 212.5 | 183.9 | 28.6 |
| 97°F | 215.7 | 186.9 | 28.8 |
| 98°F | 218.9 | 190.0 | 29.0 |
| 99°F | 222.2 | 193.0 | 29.2 |
| 100°F | 225.5 | 196.1 | 29.4 |
| 101°F | 228.8 | 199.3 | 29.6 |
| 102°F | 232.2 | 202.4 | 29.8 |
| 103°F | 235.6 | 205.6 | 29.9 |
| 104°F | 239.0 | 208.8 | 30.1 |
| 105°F | 242.4 | 212.1 | 30.3 |
| 106°F | 245.9 | 215.4 | 30.5 |
| 107°F | 249.5 | 218.8 | 30.7 |
| 108°F | 253.0 | 222.2 | 30.9 |
| 109°F | 256.6 | 225.6 | 31.0 |
| 110°FTypical cond saturation | 260.3 | 229.0 | 31.2 |
| 111°F | 263.9 | 232.5 | 31.4 |
| 112°F | 267.6 | 236.1 | 31.5 |
| 113°F | 271.4 | 239.7 | 31.7 |
| 114°F | 275.1 | 243.3 | 31.9 |
| 115°F | 279.0 | 246.9 | 32.0 |
| 116°F | 282.8 | 250.6 | 32.2 |
| 117°F | 286.7 | 254.3 | 32.4 |
| 118°F | 290.6 | 258.1 | 32.5 |
| 119°F | 294.6 | 261.9 | 32.7 |
| 120°F | 298.6 | 265.8 | 32.8 |
| 121°F | 302.6 | 269.7 | 33.0 |
| 122°F | 306.7 | 273.6 | 33.1 |
| 123°F | 310.8 | 277.6 | 33.2 |
| 124°F | 315.0 | 281.6 | 33.4 |
| 125°F | 319.2 | 285.7 | 33.5 |
| 126°F | 323.4 | 289.8 | 33.6 |
| 127°F | 327.7 | 293.9 | 33.8 |
| 128°F | 332.0 | 298.1 | 33.9 |
| 129°F | 336.4 | 302.4 | 34.0 |
| 130°F | 340.7 | 306.6 | 34.1 |
| 139°F | 382.1 | 347.3 | 34.8 |
| 140°F | 386.9 | 352.1 | 34.9 |
| 141°F | 391.8 | 356.9 | 34.9 |
| 142°F | 396.7 | 361.7 | 35.0 |
| 143°F | 401.6 | 366.6 | 35.0 |
| 144°F | 406.6 | 371.6 | 35.0 |
| 145°F | 411.7 | 376.6 | 35.0 |
| 146°F | 416.7 | 381.7 | 35.1 |
| 147°F | 421.9 | 386.8 | 35.1 |
| 148°F | 427.0 | 392.0 | 35.0 |
| 149°F | 432.2 | 397.2 | 35.0 |
| 150°F | 437.5 | 402.5 | 35.0 |
| Temp (°C) | Bubble (kPa) | Dew (kPa) | Glide (kPa) |
|---|---|---|---|
| -40°C | 19 | -16 | 35 |
| -39°C | 25 | -11 | 36 |
| -38°C | 30 | -7 | 37 |
| -37°C | 37 | -2 | 38 |
| -36°C | 43 | 3 | 40 |
| -35°C | 50 | 8 | 41 |
| -34°C | 56 | 14 | 43 |
| -33°C | 63 | 19 | 44 |
| -32°C | 71 | 25 | 45 |
| -31°C | 78 | 31 | 47 |
| -30°C | 86 | 37 | 48 |
| -29°C | 94 | 44 | 50 |
| -28°C | 102 | 51 | 52 |
| -27°C | 111 | 57 | 53 |
| -26°C | 120 | 65 | 55 |
| -25°C | 129 | 72 | 57 |
| -24°C | 138 | 80 | 58 |
| -23°C | 148 | 88 | 60 |
| -22°C | 158 | 96 | 62 |
| -21°C | 168 | 105 | 63 |
| -20°C | 179 | 113 | 65 |
| -19°C | 190 | 122 | 67 |
| -18°C | 201 | 132 | 69 |
| -17°C | 212 | 142 | 71 |
| -16°C | 224 | 152 | 73 |
| -15°C | 237 | 162 | 75 |
| -14°C | 249 | 173 | 77 |
| -13°C | 262 | 184 | 79 |
| -12°C | 276 | 195 | 81 |
| -11°C | 289 | 206 | 83 |
| -10°C | 303 | 219 | 85 |
| -9°C | 318 | 231 | 87 |
| -8°C | 333 | 244 | 89 |
| -7°C | 348 | 257 | 91 |
| -6°C | 364 | 270 | 94 |
| -5°C | 380 | 284 | 96 |
| -4°C | 396 | 298 | 98 |
| -3°C | 413 | 313 | 100 |
| -2°C | 431 | 328 | 103 |
| -1°C | 448 | 343 | 105 |
| 0°CH₂O freeze | 467 | 359 | 107 |
| 1°C | 485 | 376 | 109 |
| 2°C | 504 | 393 | 112 |
| 3°C | 524 | 410 | 114 |
| 4°CAC evap target | 544 | 427 | 117 |
| 5°C | 565 | 446 | 119 |
| 6°C | 586 | 464 | 122 |
| 7°C | 607 | 483 | 124 |
| 8°C | 629 | 503 | 127 |
| 9°C | 652 | 523 | 129 |
| 10°C | 675 | 544 | 132 |
| 11°C | 699 | 565 | 134 |
| 12°C | 723 | 586 | 137 |
| 13°C | 748 | 608 | 139 |
| 14°C | 773 | 631 | 142 |
| 15°C | 799 | 654 | 144 |
| 16°C | 825 | 678 | 147 |
| 17°C | 852 | 703 | 149 |
| 18°C | 880 | 727 | 152 |
| 19°C | 908 | 753 | 155 |
| 20°C | 936 | 779 | 157 |
| 21°CRoom T | 966 | 806 | 160 |
| 22°C | 996 | 833 | 162 |
| 23°C | 1,026 | 861 | 165 |
| 24°C | 1,057 | 890 | 168 |
| 25°C | 1,089 | 919 | 170 |
| 26°C | 1,121 | 949 | 173 |
| 27°C | 1,155 | 979 | 176 |
| 28°C | 1,188 | 1,010 | 178 |
| 29°C | 1,223 | 1,042 | 181 |
| 30°C | 1,258 | 1,075 | 183 |
| 31°C | 1,294 | 1,108 | 186 |
| 32°C | 1,330 | 1,142 | 188 |
| 33°C | 1,367 | 1,176 | 191 |
| 34°C | 1,405 | 1,212 | 193 |
| 35°CAHRI design ambient | 1,444 | 1,248 | 196 |
| 36°C | 1,483 | 1,285 | 198 |
| 37°C | 1,523 | 1,322 | 201 |
| 38°C | 1,564 | 1,361 | 203 |
| 39°C | 1,605 | 1,400 | 205 |
| 40°C | 1,648 | 1,440 | 208 |
| 41°C | 1,691 | 1,481 | 210 |
| 42°C | 1,735 | 1,522 | 212 |
| 43°CTypical cond saturation | 1,779 | 1,565 | 214 |
| 44°C | 1,825 | 1,608 | 217 |
| 45°C | 1,871 | 1,652 | 219 |
| 46°C | 1,918 | 1,697 | 221 |
| 47°C | 1,966 | 1,743 | 223 |
| 48°C | 2,015 | 1,790 | 225 |
| 49°C | 2,064 | 1,838 | 226 |
| 50°C | 2,115 | 1,886 | 228 |
| 51°C | 2,166 | 1,936 | 230 |
| 52°C | 2,218 | 1,987 | 232 |
| 53°C | 2,271 | 2,038 | 233 |
| 54°C | 2,325 | 2,091 | 234 |
| 55°C | 2,381 | 2,145 | 236 |
| 56°C | 2,438 | 2,202 | 237 |
| 57°C | 2,495 | 2,258 | 238 |
| 58°C | 2,552 | 2,314 | 239 |
| 59°C | 2,609 | 2,370 | 240 |
| 60°C | 2,668 | 2,427 | 241 |
| 61°C | 2,728 | 2,487 | 241 |
| 62°C | 2,790 | 2,548 | 241 |
| 63°C | 2,852 | 2,611 | 242 |
| 64°C | 2,916 | 2,674 | 242 |
| 65°C | 2,980 | 2,739 | 242 |
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-407C 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. The most common R-22 drop-in retrofit. Substantial temperature glide (~7-8 K) — TXV systems should be retuned and EXV is preferred for new equipment. Closely matches R-22 operating pressures.
Blend composition
- R-3223.0%
- R-12525.0%
- R-134a52.0%
Trade names
- Suva 407CChemours
- Forane 407CArkema
- Genetron 407CHoneywell
Common applications
- Residential and light commercial AC (R-22 retrofit)
- Heat pumps (R-22 retrofit)
- Medium-temperature commercial refrigeration
- Chillers
Properties
- Boiling point (1 atm)-43.6°C / -46.5°F
- Critical point187.1°F at 658 PSIG
- Molar mass86.20 g/mol
- Temperature glide11.0°F
- ODP0
- GWP (AR5, 100-yr)1774
- GWP (AR6, 100-yr)1908
What is R-407C?
R-407C is a ternary blend of 23% R-32, 25% R-125, and 52% R-134a by mass [ashrae34]. It was developed in the mid-1990s as an R-22 retrofit refrigerant — designed to match R-22's pressure envelope and capacity within existing R-22 equipment while eliminating the ozone-depletion liability of R-22's chlorine content.
The retrofit application is the defining context. R-407C operates at pressures very close to R-22 across the typical residential and light commercial AC operating range, so R-22-rated equipment (compressor, condenser, evaporator, line set) can accept R-407C charge without component replacement. The required change is the lubricant — R-22 mineral oil must be replaced with POE oil, and a filter-drier change is standard practice.
Where R-407C is used
- R-22 retrofit in residential and light commercial AC systems
- R-22 retrofit in commercial chillers and heat pumps
- Medium-temperature commercial refrigeration (legacy)
- New equipment installations are rare in 2026 — R-32 and R-454B dominate new residential AC
Regulatory & phase-down status
R-407C's GWP of 1774 places it above the EPA AIM Act 700-GWP threshold for new residential AC equipment [aimact]. R-407C is not the long-term destination — it's a transitional retrofit refrigerant for existing R-22 equipment that cannot economically be replaced.
Service of existing R-407C equipment remains legal under current EPA rules. New equipment installations have shifted to R-32 / R-454B (residential AC) or R-454C / R-455A / R-744 (commercial refrigeration). R-407C is now a service-supply refrigerant for the installed retrofit base.
Service notes
POE oil required — R-22 to R-407C retrofit requires complete oil change from mineral oil to POE [ahri700]. Multiple oil flushes are typical to reduce mineral oil residue below 5%. POE is hygroscopic; vacuum to 500 microns and hold ≥30 minutes before charging.
The 11°F temperature glide affects service measurement. Use dew temperature for superheat (suction line) and bubble temperature for subcooling (liquid line). Single-curve approximation introduces measurement error equal to the glide. R-407C is zeotropic — never top-off-charge; recover and recharge by weight if a leak occurs.
Temperature glide
R-407C 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-407C 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-407C replaces
Replacements for R-407C
Reading the R-407C PT chart — significant glide, dew/bubble matter
R-407C is zeotropic with ~11°F glide. The PT chart shows two distinct curves: bubble (saturated liquid) and dew (saturated vapor). Service measurement requires selecting the correct curve based on which line of the system is being measured.
For suction-line superheat measurement, use the dew curve. The dew temperature at the measured suction pressure is the saturation reference. Using the bubble curve would understate superheat by ~11°F — large enough to cause meaningful charging errors on residential AC where superheat targets are typically 8-15°F.
For liquid-line subcooling measurement, use the bubble curve.
R-22 was pure (no glide); R-407C retrofit requires technicians to adopt the dew/bubble curve discipline that wasn't necessary for R-22. Most retrofit documentation includes pressure-temperature tables specific to R-407C with the dew column highlighted for superheat use.
Ternary HFC blend engineered for R-22 retrofit
R-407C combines three HFCs to match R-22's pressure-envelope and capacity within R-22-rated equipment. R-32 (23%, capacity contribution); R-125 (25%, flammability suppression for A1 classification); R-134a (52%, primary mass and pressure tuning).
The 52% R-134a content gives R-407C its similar pressure envelope to R-22. R-134a's NBP (−15°F) is lower than R-22's (−41°F), but the blend's effective behavior approximates R-22's pressure profile through the R-32 and R-125 contributions. The blend's pressure envelope falls within 10% of R-22 across the residential AC operating range.
The mass-weighted GWP: 0.23 × 675 + 0.25 × 3500 + 0.52 × 1430 = 155 + 875 + 744 = 1774 [ipccar5]. R-125 is the GWP-heavy component, similar to its role in R-404A and R-410A — necessary for A1 flammability suppression at the cost of higher GWP.
Pressure envelope matches R-22 within 10%
R-407C was specifically engineered for retrofit compatibility with R-22 equipment. At 70°F R-407C bubble is 140 PSIG vs R-22's 121 PSIG (CoolProp 7.2.0) — within 16%. At 95°F outdoor ambient, R-407C bubble is approximately 215 PSIG vs R-22's 181 PSIG — within 19%.
The dew pressures track R-22 more closely than the bubble pressures because R-22 is a pure refrigerant (no bubble/dew distinction). R-407C dew at 70°F is 117 PSIG — only 3% below R-22's 121 PSIG. For suction-side operation (where dew matters), the match is very close.
Standard 500 PSI manifold gauges handle R-407C across the residential AC operating range — R-22-era service equipment works for R-407C work pressure-wise. The lubricant change (mineral oil to POE) is the major service-procedure adjustment from R-22 to R-407C.
R-407C GWP 1774 — eliminated R-22 chlorine, kept HFC climate impact
R-407C was developed in the mid-1990s to address R-22's ozone-depletion problem (ODP 0.055). All three R-407C components are zero-ODP HFCs — eliminating the chlorine while preserving R-22's operational characteristics in existing equipment.
The trade-off is GWP. R-22 has GWP 1810; R-407C has GWP 1774 [ipccar5]. The reduction is small — R-407C was not designed for climate impact, just for ozone-depletion compliance. Modern policy (EPA AIM Act, EU F-Gas Regulation) targets HFC GWP and now restricts R-407C for new equipment.
For existing R-22 retrofit installations, R-407C remains the dominant choice — it's the established, well-understood retrofit blend with the widest equipment-compatibility track record. The transitional positioning is acceptable for systems with 5-10 years of remaining equipment life.
R-407C at residential and commercial AC service temperatures
R-407C saturation values across typical AC operating conditions (bubble / dew):
- 45°F (heat pump heating outdoor coil) — bubble approximately 76 PSIG / dew approximately 61 PSIG.
- 70°F (bench reference) — bubble 140 PSIG / dew 117 PSIG.
- 75°F (indoor return air) — bubble approximately 153 PSIG / dew approximately 128 PSIG.
- 80°F (warm-weather operation) — bubble approximately 168 PSIG / dew approximately 141 PSIG.
- 95°F (summer peak / AHRI condition) — bubble approximately 215 PSIG / dew approximately 180 PSIG.
For residential AC retrofit at 95°F outdoor: typical operating pressures 75-90 PSIG suction (dew curve) and 280-330 PSIG discharge (bubble curve). Compare to R-22 at 95°F (70 PSIG suction, 250 PSIG discharge) — close enough that R-22-era service equipment and procedures apply with the dew/bubble curve discipline adjustment.
R-22 to R-407C retrofit procedure
The R-22 to R-407C retrofit is well-established with extensive industry documentation. Standard procedure:
| Step | Action | | --- | --- | | 1. Recover | Recover R-22 to recovery cylinder per EPA Section 608. | | 2. Oil drain | Drain compressor crankcase mineral oil. | | 3. Flush | Flush with POE oil 2-3 times to reduce mineral oil residue below 5%. | | 4. POE charge | Refill compressor with POE oil per OEM viscosity specification. | | 5. Drier | Replace filter-drier with HFC-compatible (XH-9 or equivalent) drier. | | 6. Evacuate | Pull vacuum to 500 microns; hold ≥30 minutes. | | 7. Recharge | Charge R-407C as liquid by weight (90-95% of R-22 nameplate). | | 8. Verify | Verify capacity at design conditions. Some efficiency loss vs original R-22 is normal. |
The lubricant change is the most service-procedure-intensive step. POE oil compatibility is critical — residual mineral oil interferes with POE/HFC operation and reduces system reliability. Multiple flushes are standard; some retrofits use special flushing solvents for additional mineral oil removal.
POE oil required — mineral oil incompatibility is the defining R-22 retrofit difficulty
R-407C requires POE oil [ahri700]. R-22 systems use mineral oil or alkylbenzene — chemically non-polar lubricants compatible with HCFC refrigerants but not with HFC chemistry. Retrofitting R-22 equipment to R-407C requires complete oil change.
Mineral oil and POE are not miscible. Residual mineral oil in an R-407C system separates from the refrigerant flow, accumulates in low-flow areas (suction-line traps, accumulators, evaporator distributors), and causes compressor oil starvation. Multiple oil-change flushes during retrofit reduce mineral oil residue to acceptable levels (target below 5% residual).
The oil-change requirement is one reason R-22 retrofit to R-407C is operationally more complex than the apparent "drop-in" marketing suggests. Mechanical service is significant — drain, flush, refill, vacuum, charge — with potential for service errors at multiple points.
R-407C in the R-22 retrofit chain
R-407C is one of several R-22 retrofit refrigerants developed in the late 1990s and early 2000s. The retrofit blend taxonomy:
- R-407C (R-32/R-125/R-134a 23/25/52) — A1, GWP 1774, ~11°F glide, requires POE oil change
- R-422D (R-125/R-134a/R-600a 65.1/31.5/3.4) — A1, GWP 2729, smaller glide, mineral-oil-tolerant in some cases
- R-438A (Honeywell MO99, R-32/R-125/R-134a/R-600/R-601a) — A1, GWP 2265, designed for closer R-22 capacity match
- R-427A (Arkema Forane 427A, R-32/R-125/R-143a/R-134a) — A1, GWP 2138, designed for chiller and supermarket retrofit
R-407C captured the largest share of R-22 retrofit market because of early commercial availability, wide equipment-OEM endorsement, and operational similarity to R-22 in the field. Through the 2020s, R-407C continues to be the dominant choice for R-22 retrofit, though new R-22 retrofits are increasingly rare — full equipment replacement to R-32 or R-454B is typically more economical given the AIM Act phase-down of HFC retrofit blends themselves.
How to think about R-407C in 2026 and beyond
R-407C occupies the R-22 retrofit niche through the late 2020s. For R-22 equipment with substantial remaining service life that cannot economically be replaced with new R-32 or R-454B equipment, R-407C provides operational continuity with the ozone-depletion problem eliminated.
The economics are increasingly disfavored for new R-22 retrofits. R-22 equipment installed in the early 2000s is now 20+ years old — at or beyond typical residential AC equipment life. Major component failures (compressor, condenser leak, expansion valve failure) increasingly tip the repair-versus-replace economic calculation toward full replacement with R-32 or R-454B equipment that offers 20-30% efficiency improvement.
For existing R-407C installations (R-22 retrofits performed 2005-2020), service supply will remain available through 2030+ via reclaimed R-407C. R-407C itself faces AIM Act phase-down for new equipment (GWP 1774 above 700-GWP threshold) but service of existing equipment is unrestricted.
For service technicians, R-407C work requires dew/bubble curve discipline for the 11°F glide. PT calculators handle this automatically; manual measurement requires reading the dew column for superheat math.
Frequently asked
›What is the normal operating pressure of R-407C?
Very close to R-22. At 70°F R-407C saturation is approximately 140 PSIG bubble / 117 PSIG dew (CoolProp 7.2.0). Compare to R-22 at 70°F (121 PSIG, pure refrigerant). The bubble pressure runs slightly above R-22; the dew pressure runs slightly below.
For a properly-charged residential AC system at 95°F outdoor, expect 75-90 PSIG suction and 280-330 PSIG discharge — very similar to R-22 operating ranges.
›Can I retrofit R-22 to R-407C in my existing AC system?
Yes, with oil change. Standard retrofit procedure: (1) Recover R-22. (2) Drain mineral oil from compressor; flush with POE multiple times to reduce residual mineral oil below 5%. (3) Refill with POE oil per equipment OEM specification. (4) Replace filter-drier with HFC-compatible drier. (5) Evacuate to 500 microns and hold ≥30 minutes. (6) Charge R-407C by weight to OEM nameplate (typically 90-95% of R-22 nameplate due to slightly different volumetric capacity).
Capacity match with R-22 is within 5-10% for most residential and light commercial AC systems. Some efficiency loss vs original R-22 operation is normal; verify acceptable cooling output after retrofit.
›What does R-407C's GWP of 1774 mean?
A 1 kg release of R-407C traps approximately 1,774 times more heat over 100 years than 1 kg of CO₂ (IPCC AR5, mass-weighted from the three components) [ipccar5]. The GWP is similar to R-22's 1810 — R-407C is not a low-GWP refrigerant.
R-407C's value as an R-22 retrofit is the elimination of chlorine (zero ODP) and the operational compatibility with R-22 equipment. The GWP reduction vs R-22 is small.
›Why does R-407C have 11°F glide while R-22 has none?
R-22 is a pure single-component refrigerant — no glide. R-407C is a zeotropic blend of three components with widely different boiling points (R-32 at −61°F, R-125 at −55°F, R-134a at −15°F). The blend inherits a temperature glide of approximately 11°F at typical operating pressures.
The glide is a service-measurement complication that R-22 did not have. R-22 service procedures from the 1980s-2000s did not require dew/bubble curve discipline; R-407C service procedures do.
›What lubricant does R-407C use?
Polyolester (POE) oil [ahri700]. R-22 systems use mineral oil; retrofit to R-407C requires complete oil change with multiple flushes to reduce mineral oil residue below 5%. POE oil is hygroscopic — moisture management during retrofit is critical.
Some R-407C retrofit guidance allows mineral oil retention with reduced reliability and capacity. Best practice is full oil change to POE for long-term reliability.
›How do I measure superheat on R-407C?
Use the dew temperature at suction pressure. R-407C's 11°F glide means using the bubble curve would understate superheat by approximately 11°F.
Modern PT calculators handle the dew/bubble selection automatically when R-407C is selected.
›Is R-407C being phased out?
For new equipment, yes — R-407C's GWP 1774 is above the EPA AIM Act 700-GWP threshold for new residential AC equipment manufactured from 2025+. New residential AC uses R-32 or R-454B [aimact].
For service of existing R-407C equipment, R-407C remains legal under current EPA rules. The installed base will service with R-407C through the equipment's remaining life, then replace with new R-32 or R-454B equipment.
›Is R-407C safe to handle?
ASHRAE class A1 — non-toxic and non-flammable [ashrae34]. Standard HFC service procedures apply. EPA Section 608 certification required for service [epasec608].
Sources & citations
- [1]ASHRAE Standard 34-2022
- [2]IPCC AR5 (2014) Working Group I, Chapter 8, Table 8.A.1
- [3]EPA AIM Act — 40 CFR Part 84 Subpart BFinal Rule Oct 2021https://www.epa.gov/climate-hfcs-reduction
- [4]CoolProp 7.2.0 (Bell, Wronski, Quoilin, Lemort 2014)
- [5]AHRI Standard 700-2019
- [6]EPA Section 608 — Stationary Refrigeration and AC Regulations
- [7]EPA SNAP — R-407C acceptable for R-22 retrofit
- [8]Chemours Suva 407C / Honeywell Genetron 407C Technical Information