Heat Pump Refrigerants 2026: R-410A vs R-32 vs R-454B
Heat pump refrigerants are changing fast: the long-standard R-410A is being phased down under the AIM Act because of its high global-warming potential (GWP ~2,088), and 2025–2026 equipment now uses low-GWP alternatives — mainly R-32 (GWP ~675) and R-454B (GWP ~466). These new A2L refrigerants are mildly flammable, which changes some handling rules but not how the equipment works for you. This guide explains the shift.
A cleaner refrigerant era
R-410A is being phased down; new heat pumps use low-GWP R-32 and R-454B.
What a refrigerant does
A refrigerant is the working fluid that makes a heat pump possible. It cycles between liquid and gas, absorbing heat in one place and releasing it in another — the mechanism by which a heat pump moves heat from outside air into your home (and reverses to cool). Without refrigerant, there is no heat pump.
Every refrigerant has trade-offs in efficiency, pressure, safety and environmental impact. The environmental impact is measured by global warming potential (GWP) — how much a given mass of the refrigerant would warm the atmosphere relative to carbon dioxide if released. Reducing the GWP of refrigerants is the driving force behind the 2025–2026 transition, and it's why the refrigerant in a heat pump you buy today differs from one bought a few years ago.
Why refrigerants are changing in 2026
The change is driven by US law. The AIM Act (American Innovation and Manufacturing Act) directs the EPA to phase down high-GWP hydrofluorocarbon (HFC) refrigerants, in line with the global Kigali Amendment. The long-dominant residential refrigerant, R-410A, has a GWP around 2,088 — high enough to be targeted for phase-down.
As a result, manufacturers have transitioned new equipment to low-GWP alternatives for the 2025 model year and beyond. This is a regulatory phase-down of the high-GWP refrigerant in new equipment, not a ban on existing systems. If you're buying a heat pump in 2026, it will almost certainly use one of the new low-GWP refrigerants covered below — a quiet but significant industry shift.
R-410A: the outgoing standard
R-410A was the residential workhorse for two decades — efficient, reliable and non-flammable (safety class A1). Its drawback is its high GWP (~2,088), which made it a target under the AIM Act. New systems are moving away from it, though R-410A equipment already installed will keep running for years, and the refrigerant remains available for servicing existing systems for now.
If you already own an R-410A heat pump, there's no need to panic: it continues to work normally, and service refrigerant remains available, though prices may rise over time as supply tightens. The change primarily affects new purchases. When that R-410A system eventually retires, its replacement will use a low-GWP refrigerant.
R-32: a leading low-GWP choice
R-32 is one of the two dominant new refrigerants. It has a GWP of about 675 — roughly a third of R-410A — and is actually a single component of the R-410A blend, so it's well understood. R-32 is highly efficient (often improving system efficiency slightly), requires less refrigerant charge, and is favored by several major manufacturers, especially in mini-splits.
The trade-off is that R-32 is classified A2L — mildly flammable (more on that below). In practice this changes installation and handling rules but not day-to-day use. R-32's combination of lower GWP, good efficiency and a smaller required charge has made it a popular choice for the new generation of heat pumps, particularly ductless systems.
R-454B: the other leading choice
R-454B is the other major successor, chosen by several large North American manufacturers (notably for ducted central systems). It has an even lower GWP of about 466 and performance characteristics close to R-410A, which made it attractive as a near drop-in replacement for existing equipment designs.
Like R-32, R-454B is an A2L mildly flammable refrigerant. The industry has somewhat split between R-32 and R-454B depending on the manufacturer and equipment type, but both achieve the core goal: a large reduction in GWP versus R-410A. For a buyer, the practical differences between the two are minimal — both are efficient, low-GWP, and subject to the same A2L safety provisions.
The refrigerants compared
| Refrigerant | GWP (approx.) | Safety class | Status |
|---|---|---|---|
| R-410A | 2,088 | A1 (non-flammable) | Phasing down |
| R-32 | 675 | A2L (mildly flammable) | New standard |
| R-454B | 466 | A2L (mildly flammable) | New standard |
| R-290 (propane) | ~3 | A3 (flammable) | Emerging (monobloc) |
The headline is the dramatic GWP reduction — the new refrigerants cut potential climate impact by roughly two-thirds to three-quarters versus R-410A. R-290 (propane), with a near-zero GWP, is emerging in some self-contained ‘monobloc’ units but is more flammable and less common in US split systems so far.
What 'A2L mildly flammable' means
The new refrigerants carry an A2L safety classification — ‘A’ for low toxicity, ‘2L’ for mild flammability with a low burning velocity. This is a real but modest property: A2L refrigerants are far harder to ignite than the highly flammable A3 refrigerants (like propane) and require specific conditions to burn.
For homeowners, A2L changes little in daily life — the equipment is engineered with leak detection, mitigation features and charge limits to manage the small risk. What it does change is that installers must follow updated codes and use A2L-rated equipment and practices, and that DIY refrigerant work is even more clearly a job for certified professionals. Modern A2L systems are designed and certified to be safe in normal residential use.
What this means for buyers in 2026
If you're buying a heat pump in 2026, here's the practical reality: your new system will almost certainly use R-32 or R-454B, you don't need to choose the refrigerant (it's determined by the model), and the unit will work exactly as you'd expect — efficiently and reliably. The transition is largely invisible to the end user.
The main buyer considerations are to ensure your installer is trained and equipped for A2L refrigerants (reputable installers are) and to be aware that you're getting current, future-proof equipment rather than soon-to-be-superseded R-410A. There's no reason to delay a purchase over the refrigerant change — new equipment is fully available and a smart, low-GWP choice. Price your system with the Cost Calculator.
If you own an older R-410A system
Owners of existing R-410A (or older R-22) systems sometimes worry the phase-down strands them. It doesn't: your system keeps working, and service refrigerant remains available, though R-410A prices may climb gradually as supply tightens, much as R-22 did during its earlier phase-out. There's no requirement to replace a working system.
The practical implication is mostly about timing your eventual replacement. When your current system nears the end of its 15–20 year life, its replacement will use a low-GWP refrigerant — a natural, beneficial upgrade. If you own a very old R-22 system, note that R-22 was phased out earlier and is now scarce and expensive to service, which often tips the math toward replacement. See our replacement signs guide.
Do the new refrigerants affect efficiency?
Encouragingly, the low-GWP refrigerants are generally as efficient as R-410A, and in some cases slightly more so. R-32, for example, can offer marginally better heat-transfer efficiency and requires a smaller charge. Manufacturers have engineered the new systems to meet or exceed the efficiency standards (SEER2/HSPF2) that already applied to R-410A equipment.
So the refrigerant transition doesn't ask you to trade efficiency for lower GWP — you get both. When comparing models, continue to focus on the SEER2 and HSPF2 ratings (see our SEER2 vs HSPF2 guide), confident that whichever low-GWP refrigerant the model uses, its rated efficiency is what matters for your bills.
Servicing and repairs
Servicing A2L systems requires installers and technicians to use A2L-rated tools, recovery equipment and procedures, and to hold the appropriate EPA certification (refrigerant handling is regulated under EPA Section 608). For homeowners this simply reinforces a rule that always applied: never attempt refrigerant work yourself — it's illegal without certification and now involves a mildly flammable fluid.
When choosing an installer or service company, confirm they're trained and equipped for the new refrigerants. The major manufacturers have transitioned their dealer networks, so reputable companies are ready. Routine homeowner maintenance — filter changes, keeping the outdoor unit clear — is unaffected; see our maintenance schedule.
The future of refrigerants
The 2025–2026 shift to R-32 and R-454B is a major step, but the direction is toward ever-lower GWP. Natural refrigerants like R-290 (propane) with near-zero GWP, and CO2 (R-744) in some applications, are gaining ground, especially in self-contained monobloc heat pumps and heat pump water heaters where the refrigerant is fully sealed in a factory-built unit.
As regulations tighten further over the coming years, expect natural and ultra-low-GWP refrigerants to expand. For a 2026 buyer, today's R-32/R-454B equipment is firmly current and will remain serviceable for its full life — you're not buying something about to be superseded. The refrigerant story is one of steady environmental improvement, and current equipment sits squarely on the right side of it.
The environmental payoff
The refrigerant transition matters because refrigerant leakage is a real climate factor. By cutting GWP from ~2,088 (R-410A) to ~466–675 (R-454B/R-32), the new equipment dramatically reduces the warming impact of any refrigerant that escapes during the system's life or at end-of-life if not properly recovered. Combined with the heat pump's already-large carbon savings over fossil heating (see our carbon footprint guide), the low-GWP refrigerants make an already-green technology greener.
Proper refrigerant recovery at end-of-life remains important regardless of type — which is another reason to use certified professionals for installation, service and decommissioning. The combination of high efficiency, electrification of heating, and low-GWP refrigerants is what makes the modern heat pump a genuine climate solution, not just an efficient appliance.
The verdict on refrigerants
The refrigerant change is good news executed quietly. R-410A's high GWP made it a phase-down target, and 2025–2026 heat pumps now use low-GWP R-32 or R-454B — cutting climate impact by two-thirds or more while matching or beating R-410A's efficiency. The A2L mild-flammability classification changes installer practices, not your daily experience, and existing R-410A systems keep working.