R22 vs R32: Two Generations of Residential AC Refrigerant
Updated October 20, 2026
R-22 is the legacy HCFC residential AC refrigerant (banned for production 2020); R-32 is the modern A2L HFC replacement. Different lubricants (MO vs POE), different safety classes (A1 vs A2L), different pressure envelopes (R-32 ~70% higher). Full equipment replacement is the only path.
PT curves, overlaid
Both refrigerants are pure or near-azeotropic — single curve per series.
Pressure comparison at service temperatures
Side-by-side pressure values at common service temperatures, computed from CoolProp 7.2.0. Useful for retrofit feasibility — pressure deltas within ±20% typically allow retrofit-compatible service equipment; larger deltas require component pressure-rating review.
| Temperature | R-22 | R-32 | Δ vs R-22 |
|---|---|---|---|
| −20°F | 10 PSIG | 27 PSIG | +162.6% |
| 0°F | 24 PSIG | 49 PSIG | +104.9% |
| 40°F | 69 PSIG | 121 PSIG | +76.4% |
| 70°F | 121 PSIG | 206 PSIG | +69.5% |
| 95°F | 182 PSIG | 303 PSIG | +66.6% |
| 120°F | 260 PSIG | 429 PSIG | +65.2% |
Pressure delta visualization: positive = R-32 runs higher than R-22; negative = lower. Service equipment pressure rating matters when delta exceeds ±20% on the discharge side. For R-22 (zeotropic blend) bubble pressure is shown; for R-32 same rule applies.
Property differences side by side
- Safety class change: R-22 (A1) → R-32 (A2L). A2L equipment requirements apply: A2L-listed equipment, charge limits set by the refrigerant's LFL and room, and refrigerant detection where the standard requires it (IEC 60335-2-40).
- GWP impact: R-22 = 1,810, R-32 = 675 (−63% vs R-22).
- Lubricant: R-22: MO/AB; R-32: POE. Retrofit requires oil change (mineral oil to POE).
- AIM Act status: R-32 is affected by AIM Act phase-down; the other is not. Drives new-equipment specification decisions in US market.
Properties side by side
| Property | R-22 | R-32 |
|---|---|---|
| Type | HCFC | HFC (pure) |
| ASHRAE class | A1 | A2L |
| Composition | Pure | Pure |
| GWP (100-yr) | 1,810 | 675 |
| ODP | 0.055 | 0 |
| Lubricant | MO, AB | POE |
| Boiling point @ 1 atm | −40.8°C | −51.6°C |
| Critical point | 96.2°C / 709 PSIG | 78.1°C / 824 PSIG |
| Temp glide | 0.00°F | 0.00°F |
| AIM Act affected | No | Yes |
Choose R-22 if…
Servicing existing R-22 equipment with original R-22. Reclaimed R-22 remains legal under EPA rules. Equipment design and lubricant stay matched to original specification. The trade-off is rising refrigerant cost as reclaim supply shrinks.
Choose R-32 if…
New residential AC equipment installations in markets where R-32 (vs R-454B) is the OEM choice. R-32 is a pure refrigerant (no glide, no fractionation concern), GWP 675 (below the 40 CFR 84.54 700-GWP limit for new residential & light-commercial AC and heat pumps, 84.54(a)(1),(c)(1)), and offers higher volumetric capacity than R-22 or R-410A. Some OEMs favor R-32 for new equipment while others favor R-454B.
When neither is ideal
For existing R-22 equipment needing significant work, R-22 retrofit blends (R-407C, R-422D, R-438A) buy time without equipment replacement — but those are HFC blends facing their own AIM Act phase-down. For maximum future-proofing, full equipment replacement with new R-32 or R-454B is the durable answer.
Retrofit and transition
R-22 to R-32 is NOT a retrofit — it requires full equipment replacement. Four structural blockers:
1. Safety class change (A1 → A2L). R-22 equipment is A1-rated (non-flammable refrigerant); R-32 is A2L (lower flammability). The change requires A2L-listed equipment, refrigerant detection where the standard requires it, charge limits per UL 60335-2-40 / IEC 60335-2-40, ignition-source isolation in the refrigerant circuit. Retrofitting an A1-rated chassis to A2L is not permitted under most codes and voids OEM warranty.
2. Pressure envelope mismatch. R-32 operates at approximately 70% higher pressures than R-22 across the operating envelope. At 95°F outdoor ambient, R-22 saturation is ~181 PSIG vs R-32 ~296 PSIG. R-22-rated components (condenser, line set, expansion device, compressor) are not pressure-rated for R-32 operation.
3. Lubricant incompatibility. R-22 uses mineral oil (MO); R-32 requires polyolester (POE) oil. The two lubricant classes are chemically incompatible; mixing produces sludge and accelerated component wear.
4. Compressor sizing. R-32's higher volumetric capacity means an R-32-optimized system uses a smaller compressor displacement than an R-22 system of the same cooling capacity. An R-22 compressor running R-32 would be oversized for the load, producing short-cycling and discomfort.
For systems where R-22 service is no longer viable: full system replacement with R-32 or R-454B equipment is the path. New equipment is typically more efficient than R-22-era equipment, which helps offset the replacement cost over time. For interim continuation on existing R-22 equipment: reclaimed R-22 remains legal, or HFC retrofits (R-407C, R-422D, R-438A) preserve the existing equipment chassis.
Regulatory and transition context
Both refrigerants sit in an active regulatory transition driven by climate-impact rules. The transitions affect availability, pricing, and new-equipment specification.
- AIM Act (40 CFR Part 84): US HFC production / import phase-down. Cap declines from 90% allocation (2022) to 15% by 2036. One or both refrigerants here are AIM Act-affected. US EPA restricts new residential and light-commercial air conditioners and heat pumps using a refrigerant of GWP 700 or more, effective January 1, 2025 (40 CFR 84.54(a)(1)). Limits for other equipment types differ.
- EU: Regulation (EU) No 517/2014, replaced by (EU) 2024/573 (applying from March 11, 2024); 2024/573 uses AR4 GWPs for HFCs and AR6 for other fluorinated gases (recital 8).
- Kigali Amendment to Montreal Protocol (2016): international HFC phase-down framework. The Montreal Protocol has 198 parties; 174 have ratified the Kigali Amendment (as of August 10, 2026). The AIM Act and EU F-Gas are regional implementations. Schedules differ by country group.
- ASHRAE 34-2022: safety classification (A1, A2L, A3, B1, B2L). For A2L refrigerants like R-32, R-454B, R-454C, R-455A: equipment must be A2L-certified, charge limits per IEC 60335-2-40 apply.
Why R-22 → R-32 isn't a direct retrofit
R-22 → R-32 is a full equipment-replacement decision, not a service-time swap. The barriers below are structural (equipment certification, oil chemistry, and pressure ratings), so no field checklist can bridge them. The realistic path is to continue servicing existing R-22 equipment through its useful life, then install new R-32-rated equipment at end-of-life.
- ASHRAE safety class change (A1 → A2L). R-32 requires equipment certified to UL/IEC 60335-2-40 for A2L: listed or ignition-protected equipment, room-volume charge limits, and (on larger systems) integrated leak detection. Field retrofit of A1-only equipment is not permitted; new equipment must ship with the A2L certification from the factory.
- Lubricant families don't overlap. R-22 runs on MO / AB; R-32 requires POE. Mixing families (mineral oil with POE, for example) produces oil-return failure in the evaporator within hours of operation, so a service-time swap requires a full oil change, system flush, and driver replacement — service labor that typically approaches new-equipment cost on residential-scale systems.
- Saturation pressure delta +69% at 70°F. Compressor, TXV, condenser, and service-valve ratings are engineered around R-22's envelope (121 PSIG at 70°F); running R-32 (206 PSIG) at this delta exceeds the design margins on multiple components. Retrofitting means re-rating hardware, not just changing charge.
Lifecycle and operational context
Beyond the per-service-call decision, the R-22 ↔ R-32 choice also involves regulatory and lifecycle factors. The transition direction (which is the predecessor, which is the successor) is driven by climate policy and the AIM Act phase-down, not technical preference alone.
- GWP profile: R-22 = 1,810 GWP; R-32 = 675 GWP. Switching from R-22 to R-32 reduces direct refrigerant climate impact by 63%.
- AIM Act exposure: R-32 is AIM Act-affected; R-22 is not — the transition increases regulatory exposure (unusual direction). One or both have a GWP of 700 or more: US EPA restricts new residential and light-commercial AC and heat pumps at that level, effective January 1, 2025 (40 CFR 84.54(a)(1)). Limits for other equipment types differ.
- EU (Regulation (EU) No 517/2014, replaced by (EU) 2024/573): R-22 (GWP 1,810) is below every Regulation (EU) No 517/2014 Annex III GWP threshold. R-32 (GWP 675) meets 2 Annex III placing-on-the-market prohibitions; the earliest is Refrigerators and freezers for commercial use (hermetically sealed equipment) (GWP ≥ 150) from January 1, 2022.
- Service supply outlook: Service supply of AIM Act-affected refrigerants persists during phase-down via reclaimed and allocated production, with prices rising as supply tightens. Plan for refrigerant cost escalation over equipment lifetime.
- TEWI / LCCP framing: Total Equivalent Warming Impact accounts for both direct refrigerant emissions (leakage, end-of-life) and indirect emissions from equipment energy consumption. For HVAC equipment with ≤5% annual leak rate, indirect emissions typically dominate TEWI by 80-90% — meaning equipment efficiency matters more than refrigerant GWP for total climate impact. For commercial refrigeration with higher leak rates, the balance can tip toward favoring low-GWP refrigerants.
Regulatory sources: AIM Act (40 CFR Part 84), EU F-Gas Regulation 517/2014 and update 2024/573, Kigali Amendment to the Montreal Protocol (2016). GWP values on the US EPA basis (40 CFR 84 / IPCC AR4).
Service implications — R-22 → R-32
What a service technician needs to know when transitioning from R-22 to R-32 (or comparing them for new equipment specification). Two scenarios show how the difference affects a service call.
Pressure envelope check for R-22 → R-32
Scenario · Field tech needs to know: do R-22 service tools handle R-32, or does the pressure delta require new equipment? PT chart comparison at service temperatures gives the answer.
| Temp | R-22 | R-32 | Δ |
|---|---|---|---|
| 40°F | 69 PSIG | 121 PSIG | +76.4% |
| 70°F | 121 PSIG | 206 PSIG | +69.5% |
| 95°F | 182 PSIG | 303 PSIG | +66.6% |
Service-side implications: lubricant and safety
Scenario · Beyond pressure envelope, the switch from R-22 to R-32 affects lubricant, safety class, and operating procedure.
| Concern | R-22 | R-32 | Action |
|---|---|---|---|
| Lubricant | MO/AB | POE | Oil change required |
| Safety class | A1 | A2L | A2L equipment |
| Glide | 0.0°F | 0.0°F | Minor |
When to use which tool for this comparison
- R-22 full reference — properties, PT chart, lubricant, retrofit options for R-22.
- R-32 full reference — properties, PT chart, lubricant, retrofit options for R-32.
- PT Comparison Tool — overlay any 2-4 refrigerants' PT curves interactively.
- Retrofit Compatibility Calculator — five-criterion compatibility analysis with verdict.
- Refrigerant Comparison Guide — long-form sourced reference for all common HVAC refrigerant comparisons.
Frequently asked
›Is R-32 a direct replacement for R-22?
No. R-32 is not a retrofit refrigerant for R-22 equipment — it's the modern refrigerant for new R-32-designed equipment. The differences (safety class, pressure, lubricant, capacity) require fundamentally different equipment design. The two refrigerants serve the same application (residential AC) but in completely separate equipment generations.
›Why does R-32 have higher pressures than R-22?
Smaller molecule with higher vapor pressure. R-32 (CH₂F₂, difluoromethane) is a smaller molecule than R-22 (CHClF₂, chlorodifluoromethane); at the same temperature R-32 has higher saturation pressure. R-32 at 70°F is 206 PSIG vs R-22 at 121 PSIG — about 70% higher. The pressure difference is intrinsic to the chemistry and requires equipment redesign for safe operation.
›What's R-32's GWP compared to R-22?
R-32 GWP 675 (the AIM Act figure) vs R-22 GWP 1,810. R-32 is about 63% lower GWP than R-22. R-32 sits just below the AIM Act 700-GWP threshold for new residential AC equipment. R-22 is phased out for ozone-depletion (ODP 0.055) under the Montreal Protocol — its GWP wasn't the binding regulatory concern, but R-32's better GWP is part of the modern transition story.
›Is R-32 flammable? Should I worry?
R-32 is ASHRAE class A2L — lower flammability with low burning velocity (≤10 cm/s) and limited heat of combustion. A2L equipment includes A2L-listed equipment, refrigerant detection where the standard requires it, charge limits, and ignition-source isolation that mitigate the flammability risk to acceptable levels. R-32 has been deployed in millions of installations globally (predominantly Japan, Europe, Australia) with strong safety record. For homeowners: properly-installed R-32 equipment is safe; the A2L classification matters for technician procedures, not for everyday operation.
›Should I retrofit my R-22 system or replace it with R-32 equipment?
Retrofit to R-32 is not possible (equipment must be A2L-rated, which old R-22 equipment isn't). The realistic options for R-22 equipment: (1) continue on reclaimed R-22, (2) retrofit to a mineral-oil-compatible HFC blend like R-422D or R-438A as an interim bridge, (3) full replacement with new R-32 or R-454B equipment. The choice depends on equipment age, condition, and capital availability. Equipment over 15 years old with significant repair needs typically justifies replacement.
›What lubricant does each refrigerant use?
R-22 uses mineral oil (MO) or alkylbenzene (AB) — the legacy CFC/HCFC era lubricants. R-32 requires polyolester (POE) oil — the HFC/HFO era lubricant. POE is hygroscopic (absorbs water aggressively) and requires more careful moisture management during service. The lubricant change is one of the structural blockers preventing R-22 to R-32 retrofit.
›Why didn't R-32 replace R-22 directly in 2010?
Timeline. R-32 was not widely available as a residential AC refrigerant until around the mid-2010s. When R-22 was phased out of new equipment in 2010, R-410A (HFC blend, A1 non-flammable) was the dominant replacement — R-410A's A1 safety class matched the existing R-22 equipment design paradigm. R-32 only became the new-equipment standard in 2024-2025 when AIM Act pressure on R-410A's GWP (2,088) made the A2L transition unavoidable.
Related
R-22 PT chart
Full reference: PT chart, properties, retrofit guidance.
R-32 PT chart
Full reference: PT chart, properties, retrofit guidance.
R-22 operating pressures
Suction/discharge ranges by ambient + diagnostic procedure.
R-32 operating pressures
Suction/discharge ranges by ambient + diagnostic procedure.