R-454B and the 2026 Refrigerant Transition (A2L)

The AIM Act phasedown, in plain terms

The federal AIM Act (American Innovation and Manufacturing Act) directs the EPA to phase down production and import of high-global-warming-potential (GWP) hydrofluorocarbon (HFC) refrigerants — stepping toward an 85% reduction by 2036. The workhorse refrigerant in most air conditioning and heat pumps, R-410A, has a GWP around 2,088, which put it squarely in the crosshairs. The result: the whole industry has moved new equipment to lower-GWP refrigerants, and that shift landed on the market in 2025.

This isn't a VRF story — it's an everything story. RTUs, split systems, and VRF all made the same jump. That matters, because it removes the reflex that "just replacing the rooftop unit" avoids the transition. It doesn't.

Meet R-454B and R-32

The two dominant replacements:

R-454B — GWP ≈ 466 (about 78% lower than R-410A). Adopted by many manufacturers as the R-410A successor across residential and light-commercial equipment, including VRF lines.
R-32 — GWP ≈ 675. Widely used globally and by several manufacturers, single-component (easier to reclaim/recharge).

Both are classified A2L: low toxicity, mildly flammable. "Mildly" is doing real work here — A2Ls are far harder to ignite than propane-class (A3) refrigerants, but they are no longer non-flammable (A1) like R-410A, and that reclassification is what drives the new install and code requirements below.

The HFC phasedown: high-GWP R-410A gives way to A2L refrigerants (R-454B, R-32) on the road to an 85% HFC reduction by 2036.

Where we are on the timeline

2022–2024: Production/import step-downs begin; manufacturers redesign for A2L.
2025: New equipment ships with A2L refrigerants; R-410A equipment manufacture winds down under EPA sector rules.
2026 (now): A2L is the baseline for new installs; codes and technician practices have caught up. R-410A remains serviceable but is on a cost curve.
Toward 2036: Continued allowance reductions toward the 85% cut — R-410A service refrigerant grows scarcer and pricier over the life of any unit bought today.

What A2L changes on site

Because A2Ls are mildly flammable, installation follows UL 60335-2-40 and the updated model codes (IMC/IRC/IFC). In practice:

Refrigerant charge limits per space — indoor charge is capped based on room size, which can affect indoor-unit selection and layout.
Leak detection & mitigation — A2L systems include refrigerant sensors and mitigation logic (e.g. shutting valves, running the fan to disperse) built into the equipment.
Technician handling — A2L-rated recovery equipment, gauges, and practices; sparkless tools and ventilation during service. Any competent installer is already trained on this, but "any tech off the street" is less true than it was for R-410A.
Permitting — AHJs are updating to the A2L code editions; expect the newer standards to be referenced on plan review.

None of this is exotic in 2026 — it's the new normal — but it does reward choosing an installer who's fluent in A2L design, and it's one more reason the era of the ultra-cheap commodity install is fading on every system type.

Pricing & availability

New-equipment prices rose in 2024–25 across the board — redesigned coils, controls, and sensors for A2L added cost to RTUs, splits, and VRF alike. The cheap-RTU baseline many owners remember is gone.
R-410A service refrigerant is on a sunset. As allowances shrink, the cost to recharge and repair aging R-410A stock climbs — a real carrying cost over a 15–18-year RTU life.
Buying new R-410A equipment today (where still available) means buying into that sunset. If you're replacing anyway, doing it with current A2L equipment hedges the refrigerant risk instead of locking into it.

Retrofit vs. replace planning

Existing R-410A systems can keep running. There's no mandate to rip out working equipment; service continues, at gradually rising refrigerant cost.
You generally cannot "drop-in" A2L into an R-410A system — the equipment is designed and safety-rated for its refrigerant. Transition happens at replacement, not mid-life.
Plan replacements around the curve. If a system is within a few years of end-of-life, the refrigerant transition is another reason to plan the all-electric, A2L, solar-ready replacement deliberately rather than reactively after a failure.
For VRF buyers specifically: current VRF lines are A2L and long-lived (20–25 years), so a system specified now is on the right side of the phasedown for its entire service life — while its all-electric design keeps the solar-offset story intact.

The transition narrows the old "new RTU is just cheaper" gap and adds a timing argument to every replacement decision. It doesn't make VRF free — it makes the comparison fairer, which usually helps the better system.

Frequently asked questions

What is replacing R-410A?

Lower-GWP A2L refrigerants — primarily R-454B (GWP ≈ 466) and R-32 (GWP ≈ 675) — replace R-410A (GWP ≈ 2,088) in new equipment under the AIM Act HFC phasedown. New RTUs, splits, and VRF all shipped with A2L refrigerants starting in 2025.

Is R-454B flammable and is it safe?

R-454B is classified A2L: low toxicity and mildly flammable — much harder to ignite than propane-class refrigerants, but no longer non-flammable like R-410A. New equipment includes leak detection and mitigation, and installs follow UL 60335-2-40 charge limits, so it is safe when installed to code.

Do I need to replace my existing R-410A system?

No. Working R-410A systems can keep running and be serviced; there is no mandate to remove them. But R-410A service refrigerant grows scarcer and pricier over time, so plan end-of-life replacements around that curve rather than reacting after a failure.

How does the refrigerant transition affect VRF buyers?

Current VRF lines already use A2L refrigerants and last 20–25 years, so a system specified now stays on the right side of the phasedown for its whole life. The 2024–25 price rises hit all equipment types, which narrows the first-cost gap between a new RTU and new VRF.

Sources

EPA — AIM Act HFC phasedown & technology-transitions rules (epa.gov/climate-hfcs-reduction)
UL 60335-2-40 safety standard for A2L refrigerant equipment; ASHRAE 34 refrigerant safety classifications
Manufacturer A2L transition bulletins (Daikin, Mitsubishi Electric, LG, Carrier, Trane)
IMC / IRC / IFC A2L code provisions; GetVRF VRF vs. Traditional HVAC

Educational content — actual system performance, costs, and program terms vary by building and market. Get site-specific engineering and bids before deciding.

R-454B and the 2026 Refrigerant Transition