By Yevhen Kovalchuk · Updated September 21, 2026 · 8 min read
Short answer
R-410A is a non-flammable HFC blend with a GWP above 2,000. R-454B and R-32 are mildly flammable A2L refrigerants with much lower GWP, used in new equipment designed for them. R-454B is a blend that runs at pressures close to R-410A; R-32 is a single-component refrigerant with higher discharge temperatures and slightly higher capacity. None can be swapped into existing R-410A equipment.
R-454B and R-32 are lower-GWP replacements for R-410A in new air-conditioning and heat pump equipment. R-410A is non-flammable but has a global warming potential (GWP) above 2,000; R-454B (about 466) and R-32 (about 675) cut that sharply, and both are classed A2L, meaning low toxicity and mild flammability. They are designed into new equipment, not poured into old R-410A systems. This guide compares the three on the points facility teams and technicians ask about most.
How do R-454B, R-32 and R-410A compare side by side?
| Property | R-410A | R-32 | R-454B |
|---|---|---|---|
| Composition | HFC blend (R-32 / R-125, 50/50 by weight) | Single HFC (difluoromethane) | HFC/HFO blend (R-32 / R-1234yf, about 68.9/31.1) |
| ASHRAE safety class | A1 (non-flammable) | A2L (mildly flammable) | A2L (mildly flammable) |
| GWP (AR4, approx.) | 2,088 | 675 | 466 |
| Operating pressure vs R-410A | baseline | slightly higher | very close to R-410A |
| Glide | negligible (near-azeotropic) | none | small (about 1°F) |
| Typical use | legacy residential and commercial AC | residential and light commercial AC, heat pumps | new U.S. residential and commercial AC, heat pumps, some chillers |
GWP values change with the IPCC assessment report used, so always compare numbers from the same source. Composition and safety class come from the ASHRAE Standard 34 designations; confirm against the manufacturer’s current data sheet for a specific product.
Why is R-410A being replaced?
The American Innovation and Manufacturing (AIM) Act directs EPA to cut HFC production and consumption by 85% by 2036. EPA’s Technology Transitions program sets GWP limits for new equipment by subsector, and for most new comfort-cooling systems the limit is 700. R-410A is well above it. R-32 and R-454B are below it, which is why manufacturers chose them. The details and sell-through dates were revised in 2026, so read the Technology Transitions rule 2026 update and the R-410A phase-out timeline and check the current EPA page before acting on a date.
What is the difference between R-454B and R-32?
Both are A2L, but they behave differently in the field.
- Composition. R-32 is one molecule, so it does not fractionate and can be topped off like R-410A’s near-azeotropic blend. R-454B is a zeotropic blend with a small temperature glide, so charge should be added as a liquid and the manufacturer’s procedure followed.
- Pressure. R-454B runs at pressures very close to R-410A, which lets manufacturers reuse many component designs. R-32 runs a bit higher.
- Discharge temperature. R-32 has a noticeably higher compressor discharge temperature than R-410A. That affects compressor design, oil selection and protection logic. R-454B is closer to R-410A.
- Capacity and charge. R-32 has higher volumetric capacity per unit of refrigerant and needs a smaller charge by mass for the same duty. This also helps with A2L charge limits in occupied spaces.
- Flammability. The lower flammability limit of R-32 is about 14% by volume, and its burning velocity is low (under 4 inches per second, which is the “L” in A2L). R-454B is in the same class with a slightly different profile. Neither ignites easily, but both need ignition-source control and, where the equipment standard requires, leak detection and mitigation.
In North America, R-454B has been the choice of most large U.S. manufacturers for ducted systems, while R-32 is common in ductless and in many global products. Availability depends on the model, so do not assume.
Can R-454B or R-32 be used in an existing R-410A system?
No. A retrofit is not a drop-in swap for three reasons:
- Equipment listing. A2L refrigerants require equipment designed and listed for them, such as sealed electrical parts, A2L-rated sensors and approved components. Using a flammable refrigerant in a system that was not evaluated for it creates a safety and code problem.
- Oil and materials. R-410A systems use POE oil, and component materials, valves and pressure controls are matched to the old refrigerant.
- Regulation. EPA’s SNAP program lists which refrigerants are acceptable for which end uses and under what conditions. A refrigerant being approved for new equipment does not make it approved as a retrofit in old equipment.
Existing R-410A systems can still be serviced with R-410A under federal rules, including reclaimed refrigerant. The practical issue is that supply of virgin R-410A is expected to get tighter and more expensive as the phasedown steps down. See what is the AIM Act HFC phasedown for the allowance schedule.
What changes for technicians and facility teams?
- Tools. A2L work calls for A2L-rated recovery machines, vacuum pumps and leak detectors where the manufacturer or code requires them. Do not assume an R-410A recovery machine is suitable.
- Cylinders. A2L cylinders have a red band at the top and use different valve fittings than R-410A cylinders, which prevents cross-connection.
- Training. Technicians need training on A2L flammability, charge limits and ventilation. Section 608 certification is still required to handle these refrigerants.
- Codes. Texas adopted the 2024 editions of the International and Uniform Mechanical Codes effective September 1, 2026, in part to address A2L. Local jurisdictions vary in what and when they enforce. Our summary is in Texas 2024 mechanical codes: what changed.
- Rooftop units. The transition affects rooftop equipment directly; see RTU basics and the A2L transition.
For the safety class itself, read A2L refrigerants explained.
Which one performs better?
Performance depends on the whole system, not just the refrigerant. Manufacturers report that R-454B equipment can match R-410A equipment in efficiency at the same pressure class, and R-32 equipment can reach similar or slightly better efficiency with a smaller charge. Real differences come from how well the coils, compressor and controls were redesigned. Compare AHRI-certified ratings (SEER2, EER2, HSPF2) for specific models instead of choosing by refrigerant alone.
What should facility owners do now?
- Make a list of equipment by refrigerant, age and capacity. Mark which units use R-410A.
- Ask suppliers which refrigerant new replacement models use and what the installation requirements are.
- Plan budgets for A2L-capable tools and training before the first A2L unit arrives.
- Keep recovery and leak records for larger systems; see EPA 608 leak repair rules.
- Check the current EPA pages for installation dates, because enforcement positions and compliance dates have changed more than once.
Frequently asked questions
Is R-454B the same as R-410A?
No. R-454B is a different, mildly flammable blend with a much lower GWP. Its pressure is close to R-410A, but it needs equipment designed for it.
Is R-32 better than R-454B?
Neither is better in every case. R-32 allows a smaller charge and is a single component, but it has higher discharge temperatures. R-454B is closer to R-410A in pressure and has the lowest GWP of the two. Manufacturers choose based on their product design.
Will R-410A become illegal to service?
Federal rules restrict new equipment and supply, not the servicing of existing R-410A systems with R-410A. Check the current EPA rules and your state and local requirements, since details have been updated several times.
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