R-22 vs R-454B: Legacy HCFC to Modern A2L Upgrade
R-22 is the legacy HCFC residential AC refrigerant (production banned 2020); R-454B is the modern A2L HFC/HFO blend replacement (R-32/R-1234yf 68.9/31.1, GWP 466). Different lubricants, different safety classes, R-454B operates at ~60% higher pressures. Full equipment replacement only — no retrofit path.
PT curves, overlaid
Solid line = bubble, dashed = dew where the refrigerant has significant temperature glide.
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 drop-in compatible service equipment; larger deltas require component pressure-rating review.
| Temperature | R-22 | R-454B | Δ vs R-22 |
|---|---|---|---|
| -20°F | 10 PSIG | 24 PSIG | +138.1% |
| 0°F | 24 PSIG | 45 PSIG | +88.4% |
| 40°F | 69 PSIG | 112 PSIG | +63.3% |
| 70°F | 121 PSIG | 191 PSIG | +56.9% |
| 95°F | 182 PSIG | 280 PSIG | +53.9% |
| 120°F | 260 PSIG | 396 PSIG | +52.2% |
Pressure delta visualization: positive = R-454B 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-454B same rule applies.
Property differences side by side
- Safety class change: R-22 (A1) → R-454B (A2L). A2L equipment requirements apply: sealed motors, charge limits, leak detection per IEC 60335-2-40.
- GWP impact: R-22 = 1,810, R-454B = 466 (-74% vs R-22). Switching reduces direct climate impact substantially.
- Lubricant: R-22: MO/AB; R-454B: POE. Retrofit requires oil change (mineral oil to POE).
Properties side by side
| Property | R-22 | R-454B |
|---|---|---|
| Type | hcfc | hfo blend |
| ASHRAE class | A1 | A2L |
| Composition | Pure | 68.9% R-32 / 31.1% R-1234yf |
| GWP (AR5) | 1810 | 466 |
| ODP | 0.055 | 0 |
| Lubricant | MO, AB | POE |
| Boiling point @ 1 atm | -40.8°C | -50.5°C |
| Critical point | 96.2°C / 709 PSIG | Blend (locus, not point) |
| Temp glide | 0.00°F | -2.32°F |
| AIM Act affected | No | No |
Choose R-22 if…
Servicing existing R-22 equipment with original R-22. Reclaimed R-22 remains legal indefinitely under EPA rules. The equipment chassis and lubricant match original specification. Rising refrigerant cost is the trade-off — service supply is reclaimed only and shrinking.
Choose R-454B if…
New residential AC equipment installations 2025+. R-454B is one of the two dominant A2L replacements for R-410A (R-32 is the other). Carrier, Trane, and Lennox have standardized on R-454B (marketed as Puron Advance) for their US residential AC lines. GWP 466 (below AIM Act 700-GWP threshold) with the lowest among A2L blends in mainstream residential use.
When neither is ideal
For existing R-22 equipment needing significant work but not yet ready for full replacement: R-22 retrofit blends (R-407C, R-422D, R-438A) preserve the existing chassis with a refrigerant + oil change. These are HFC blends facing their own AIM Act phase-down — a 5-10 year bridge, not a long-term answer. Full replacement with new R-454B or R-32 equipment is the durable path.
Retrofit and transition
R-22 to R-454B is NOT a retrofit — it requires full equipment replacement. Four structural blockers identical to the R-22 → R-32 path:
1. **Safety class change (A1 → A2L).** R-22 equipment is A1-rated. R-454B is A2L (mildly flammable). The transition requires sealed-motor design, A2L-rated leak detection, charge limits per IEC 60335-2-40, ignition-source isolation. Retrofit of A1-rated chassis to A2L is not permitted under most codes.
2. **Pressure envelope mismatch.** R-454B operates at approximately 60% higher pressures than R-22 across the operating envelope. R-22-rated components are not pressure-rated for R-454B operation.
3. **Lubricant incompatibility.** R-22 uses mineral oil (MO); R-454B requires polyolester (POE) oil. The two are chemically incompatible.
4. **Compressor sizing.** R-454B's higher volumetric capacity means an R-454B-optimized system uses smaller compressor displacement than R-22 equipment for the same capacity.
**For existing R-22 equipment, the practical paths:**
- **Continue on reclaimed R-22** — legal, increasingly expensive, sustainable for systems with no major issues - **R-22 retrofit blend** — R-407C, R-422D, R-438A, R-427A; preserves equipment chassis, adds 5-10 year service life, still faces HFC phase-down - **Full system replacement** — new R-454B equipment (or R-32, depending on OEM preference); 20-30% efficiency improvement vs R-22-era equipment; eliminates phase-down risk
**R-454B vs R-32 for new equipment:** This is the OEM-preference choice. Both are A2L. R-454B has slightly lower GWP (466 vs R-32's 675) and is preferred by Carrier/Trane/Lennox. R-32 is preferred by Daikin/Mitsubishi/LG. Performance is comparable; equipment availability and installer training in your market typically determines the choice.
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.
- EPA AIM Act (40 CFR Part 84): US HFC production / import phase-down. Cap declines from 90% allocation (2022) to 15% by 2036. Neither refrigerant is directly affected. New residential AC equipment over 700 GWP prohibited as of 2025.
- EU F-Gas Regulation (517/2014, updated 2024/573): European stationary refrigeration GWP cap typically 150 (much tighter than AIM Act). Drives earlier adoption of very-low-GWP options in European markets.
- Kigali Amendment to Montreal Protocol (2016): international HFC phase-down framework (198 countries). 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.
Standard transition procedure — R-22 → R-454B
Step-by-step service procedure for transitioning an existing R-22 system to R-454B, derived from the property differences above. Always cross-check equipment OEM service literature for the specific equipment being serviced. The steps below codify EPA Section 608 requirements (recovery, evacuation, documentation) plus refrigerant-specific accommodations for lubricant, safety class, pressure envelope, and glide differences. Skipping any of the regulatory steps (leak check, recovery, evacuation, documentation) creates compliance liability; skipping refrigerant-specific accommodations creates equipment-failure risk.
- EPA Section 608 leak-check first.Verify the existing system isn't leaking before any work. If it's leaking, find and repair the leak — adding refrigerant (existing or new) to a leaking system violates 40 CFR Part 82.
- Recover R-22. Use a recovery machine rated for A1refrigerants. Recover into properly-labeled cylinders; don't mix recovered R-22 with virgin or recovered R-454B (cross-contamination invalidates reclaim).
- Drain MO lubricant and flush. R-22 runs on MO/AB; R-454B requires POE. Drain the compressor crankcase, accumulator, and any oil traps. Flush the system with a compatible flush solvent or run POE lubricant through the system and re-drain to clear residual MO. Mixing mineral oil with POE in an HFC system produces oil-return failures within hours of operation.
- Replace filter-drier. Install a new drier rated for R-454B (POElubricant). Filter-driers are single-use after exposure to a refrigerant; the old drier may have absorbed contaminants you don't want carrying into the new charge.
- Pressure-test and evacuate to ≤500 microns. Pressure-test with dry nitrogen to verify no leaks. Pull deep vacuum and hold ≥30 minutes with vacuum pump isolated to confirm no leak-back. This step is non-negotiable — non-condensables (air, moisture) trapped in the system raise discharge pressure and damage the compressor.
- Charge R-454B by weight to nameplate — adjusted for the +54% pressure difference vs R-22. Use a calibrated recovery / charging scale. Charging by gauge feel produces frequent overcharge errors.
- Verify with SH and SC at steady state. R-454B has minimal glide (pure or near-azeotrope), so the bubble = dew curve and standard PT chart math applies. Target SC = 8-12°F for TXV systems; target SH per OEM nameplate.
- A2L safety compliance. R-454B is A2L(mildly flammable). Field retrofit of A1-only equipment to A2L generally isn't possible — equipment must be A2L-certified per UL / IEC 60335-2-40 (sealed motors, charge limits per room volume, leak detection on larger systems). The realistic path is full equipment replacement, not refrigerant swap.
- Document and label. Update the equipment data plate to reflect R-454B. EPA Section 608 requires records of refrigerant added / recovered; OEM warranty may require documentation of approved-refrigerant substitution.
Lifecycle and operational context
Beyond the per-service-call decision, the R-22 ↔ R-454B choice sits inside a broader regulatory and lifecycle context. 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 (AR5); R-454B = 466 GWP. Switching from R-22 to R-454B reduces direct refrigerant climate impact by 74%.
- AIM Act exposure: Neither refrigerant is directly affected by the AIM Act phase-down. Other regional regulations (EU F-Gas, Kigali signatory implementations) may still apply.
- EU F-Gas Regulation: Both refrigerants exceed the EU F-Gas 150 GWP cap for new stationary refrigeration. Selection in European market favors very-low-GWP HFOs and natural refrigerants.
- Service supply outlook: Neither refrigerant faces near-term supply constraints from US AIM Act phase-down. Pricing follows normal commodity dynamics.
- 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: EPA AIM Act (40 CFR Part 84), EU F-Gas Regulation 517/2014 and update 2024/573, Kigali Amendment to the Montreal Protocol (2016), Japan Fluorocarbon Emissions Control Law. GWP values per IPCC AR5 (2013) WG-I Table 8.A.1.
Service implications — R-22 → R-454B
What a service technician needs to know when transitioning from R-22to R-454B (or comparing them for new equipment specification). Two real-world scenarios show how the difference plays out in practice.
Pressure envelope check for R-22 → R-454B
Scenario · Field tech needs to know: do R-22 service tools handle R-454B, or does the pressure delta require new equipment? PT chart comparison at service temperatures gives the answer.
| Temp | R-22 | R-454B | Δ |
|---|---|---|---|
| 40°F | 69 PSIG | 112 PSIG | +63.3% |
| 70°F | 121 PSIG | 191 PSIG | +56.9% |
| 95°F | 182 PSIG | 280 PSIG | +53.9% |
Service-side implications: lubricant and safety
Scenario · Beyond pressure envelope, the switch from R-22 to R-454B affects lubricant, safety class, and operating procedure.
| Concern | R-22 | R-454B | Action |
|---|---|---|---|
| Lubricant | MO/AB | POE | Oil change required |
| Safety class | A1 | A2L | A2L equipment |
| Glide | 0.0°F | 2.3°F | Minor |
When to use which tool for this comparison
- R-22 full reference — properties, PT chart, lubricant, retrofit options for R-22.
- R-454B full reference — properties, PT chart, lubricant, retrofit options for R-454B.
- 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-454B a direct replacement for R-22?
No. R-454B is the modern refrigerant for new R-454B-designed equipment — not a retrofit refrigerant for R-22 equipment. The safety class change (A1 to A2L), pressure envelope difference (~60% higher), lubricant change (mineral oil to POE), and capacity differences all require fundamentally different equipment design. The two refrigerants serve the same residential AC application in completely separate equipment generations.
›What's the difference between R-454B and R-32?
Both are A2L refrigerants for residential AC. R-454B is a 68.9/31.1 R-32/R-1234yf blend with GWP 466 and very small glide (~2°F). R-32 is pure (no glide) with GWP 675. R-454B is preferred by Carrier, Trane, Lennox; R-32 is preferred by Daikin, Mitsubishi, LG. Performance is comparable. The R-454B blend's lower GWP comes from the R-1234yf component; the slight glide is the trade-off.
›What's R-454B's GWP compared to R-22?
R-454B GWP 466 per IPCC AR5 vs R-22 GWP 1810. R-454B is about 74% lower GWP than R-22, and the lowest GWP among the mainstream A2L residential AC choices. R-22 is being phased out for ozone-depletion concerns (ODP 0.055) under the Montreal Protocol; R-454B has zero ODP and clears the AIM Act 700-GWP threshold by a wider margin than R-32 does.
›Is R-454B safe to handle?
It's ASHRAE class A2L — mildly flammable with low burning velocity. A2L equipment design (sealed motors, leak detection, charge limits, ignition-source isolation) mitigates the flammability risk to acceptable levels. The R-1234yf component is itself A2L. R-454B has been deployed extensively in US residential AC since 2024 with strong safety record. For homeowners: A2L equipment is safe in normal operation; the classification matters for technician procedures, not for everyday use.
›Does R-454B have temperature glide?
Yes — about 2°F at typical operating pressures. This is very small (compare R-407C's 11°F or R-454C's 14°F). The small glide is a feature of the carefully-engineered 68.9/31.1 composition — the blend is intentionally near-azeotropic, simplifying service measurement and avoiding the bubble/dew curve complexity that high-glide blends require. For practical purposes R-454B can often be treated like a near-azeotrope for service measurements.
›What lubricant does R-454B use?
Polyolester (POE) oil — same as R-410A and R-32. Mineral oil (R-22's lubricant) and alkylbenzene are not compatible. POE is hygroscopic, so vacuum and filter-drier handling are important during service.
›Should I install R-454B or R-32 equipment?
Equipment availability in your market is the primary driver. Carrier, Trane, Lennox dealers will lead with R-454B; Daikin, Mitsubishi, LG dealers lead with R-32. Performance is comparable between the two (R-454B slightly lower GWP, R-32 higher discharge temperature). For homeowners, the choice between A2L refrigerants is rarely the binding constraint; pick the equipment brand that fits your application and trust the OEM's refrigerant selection.
R-22 full reference
PT chart, properties, retrofit guidance.
R-454B full reference
PT chart, properties, retrofit guidance.