Why R-22 systems need a plan
EPA ended production and import of HCFC-22 on January 1, 2020. After that, only recycled, reclaimed or previously produced R-22 can be used to service existing equipment. EPA rules have also barred selling pre-charged R-22 appliances made on or after January 1, 2010. That leaves three choices for a working R-22 system: keep servicing it with recycled, reclaimed or previously produced R-22, retrofit it to an HFC blend, or replace it. In residential and light-commercial AC, EPA lists R-407C and R-422B as acceptable for retrofit and new equipment, and R-427A for retrofit.
Side by side
| R-22 | R-407C | R-422B | R-427A | |
|---|---|---|---|---|
| Makeup | Single HCFC | R-32 / R-125 / R-134a, 23 / 25 / 52 | R-125 / R-134a / R-600a, 55 / 42 / 3 | R-32, R-125, R-143a, R-134a |
| Safety class | A1 | A1 | A1 | A1 |
| GWP (IPCC AR4) | 1,810 | 1,774 | 2,525 | 2,138 |
| Oil | Mineral or alkylbenzene | POE; residual mineral oil about 5% or less | Usually no change; add POE if oil return is poor | POE recommended; 20% POE or a full change |
| Dew pressure at 40°F | 68.6 psig | 63.2 psig | 59.4 psig | 61.2 psig |
| Bubble pressure at 110°F | 226.4 psig | 260.3 psig | 229.8 psig | 249.5 psig |
| Glide near 40°F evaporating | None | 11.1°F | 7.6°F | 10.5°F |
| Capacity vs R-22 (maker) | 98 to 106% in cooling | Similar in most systems | About 3% lower at 45°F evaporating | |
| Charge vs original R-22 | 90 to 95% by weight | Start near 85%, finish near 95% | Start at 90%, as liquid |
All three are zeotropic blends with real glide, so read the dew column for superheat and the bubble column for subcooling (why), and charge them as liquid.
R-407C
Chemours' R-407C retrofit guidelines require polyolester (POE) oil, with residual mineral oil around 5% or less of the total, and Chemours' R-407C and R-410A bulletin says three oil changes are generally recommended when converting a system to HFC refrigerants and POE. Copeland's changeover guidelines approve only POE for R-407C and R-427A in its compressors, recommend flushing to no more than 5% residual mineral oil, and say some systems perform adequately with up to 10%. Chemours reports a slightly higher discharge pressure than with R-22. Copeland also notes that with glide blends such as R-407C and R-427A, refrigerant entering the evaporator is about 10°F colder than the vapor leaving it, so low-pressure controls set for R-22 may need new cut-in and cut-out points.
R-422B
Chemours sells R-422B as Freon NU-22B. Its guidelines say it works with traditional and newer lubricants and that in most cases no change of lubricant type is needed. If oil return looks erratic, Chemours advises adding POE at about 20% of the total oil charge, and recommends a one-time POE change for systems with Trane 3-D or Danfoss SM scroll compressors. It reports similar cooling capacity and efficiency to R-22 in most systems, with a lower discharge temperature, and says systems can be topped off without removing the whole charge.
R-427A
Arkema sells R-427A as Forane 427A. Its retrofit guidelines say it is compatible with mineral and alkylbenzene oil but not fully miscible, and recommend converting 20% of the oil to POE or changing over completely; Trane 3-D, Danfoss SM and all screw compressors need a full POE change. Arkema's procedure adds that R-427A tolerates a high residual of the original oil, so one oil change is usually enough. Arkema puts the capacity loss at about 3% at a 45°F evaporator and expects slightly lower suction and slightly higher discharge pressure than R-22.
Replacing the system instead
R-410A is not a retrofit option for R-22 equipment: EPA lists it for new residential AC equipment only. It also runs far higher pressures, 118.8 psig at 40°F against 68.6 psig for R-22, and Chemours notes that HFCs such as R-410A are miscible with POE oil but not with mineral oil. Replacement systems are matched sets; Payne's R-454B heat pump instructions, for example, open with "For use with R-454B indoor units only."
Since January 1, 2025, EPA's Technology Transitions rule has limited new residential and light-commercial AC and heat pump systems to refrigerants under 700 GWP. Under the final rule effective July 27, 2026, a new R-410A system can still be installed only if every specified component was manufactured in or imported into the US before January 1, 2025. Otherwise a replacement uses an A2L refrigerant such as R-454B or R-32. Check the manufacturer's instructions on whether the existing line set can be reused.
Steps the retrofit guides share
- Recover the full R-22 charge first.
- Change oil as the guide for that refrigerant and compressor requires.
- Replace the filter drier.
- Charge as liquid, start below the original R-22 charge, and finish by superheat or subcooling.
- Label the system with the refrigerant and oil now in it.