What Refrigerant Does a New AC Use in 2026? R-454B vs R-410A, Explained

What refrigerant does a new AC use in 2026 — R-454B or R-410A?

Since January 1, 2025, virtually all newly manufactured U.S. home central air conditioners and heat pumps use a low-GWP A2L refrigerant — most commonly R-454B, with some R-32 — instead of R-410A. The change is federal law, and it applies to new equipment installed across Ontario, Riverside, and the rest of the Inland Empire. If you buy a new system this year, it will almost certainly be charged with R-454B, not the R-410A your old unit likely uses.

Why did the refrigerant change on January 1, 2025?

The switch is driven by two federal actions. The American Innovation and Manufacturing (AIM) Act of 2020 directs the EPA to phase down high-GWP hydrofluorocarbons (HFCs). EPA's Technology Transitions rule then set the hard deadline: newly manufactured residential AC and heat pump systems must use a refrigerant with a Global Warming Potential (GWP) under 700 as of January 1, 2025.

R-410A, the standard for two decades, has a GWP of about 2,088 — far above the new 700 cap. That is why manufacturers redesigned entire product lines around lower-GWP A2L refrigerants, updating compressors, coils, metering devices, and safety controls in the process. California layers its own oversight on top: the state's Refrigerant Management Program, run by the Air Resources Board, has long pushed the HVAC industry toward lower-GWP refrigerants, so the Inland Empire sees this transition sooner and more completely than some other regions. If you are weighing a purchase, our guide on buying a new AC in 2026 and the A2L refrigerant questions walks through what to ask a contractor.

R-410A vs R-454B vs R-32: how they compare

The three refrigerants you will hear about differ mainly in GWP, flammability class, and where they are used. R-454B has become the dominant choice for ducted central systems in the U.S. because its performance profile is close to R-410A, which let manufacturers adapt existing platforms. R-32 has a slightly higher GWP (675) but is a single component, making it popular in ductless mini-splits and some packaged units. Both come in comfortably under the 700 GWP cap. Here is the side-by-side.

What does A2L mean — is R-454B dangerous?

A2L stands for "mildly flammable," and it is the point that worries most homeowners. It should not. A2L refrigerants have a low burning velocity and require high ignition energy — they are much harder to ignite than propane-type A3 refrigerants used in some appliances. In normal operation the refrigerant is sealed inside the coil and lines.

• New A2L equipment is built to UL 60335-2-40 and ASHRAE 15 safety standards.
• Systems include leak-detection sensors that shut down or ventilate if refrigerant escapes.
• Mitigation features (like circulation fans) disperse any leak below flammable concentration.
• A2L refrigerant charge limits and installation clearances are set by code, not guesswork.

For a deeper look at the flammability question, see is R-454B safe? The A2L refrigerant explained. The short version: a properly installed R-454B system is safe for a California home.

Does switching to R-454B change efficiency or my energy bills?

Not in a way that hurts you. R-454B is thermodynamically similar to R-410A, so manufacturers have kept — and in many cases improved — efficiency in the new generation of equipment. What actually drives your summer cooling cost is the system's SEER2 rating and correct sizing, not the refrigerant label on the sticker.

New R-454B condensers are being built to meet the current federal efficiency minimums, which are measured under the SEER2 test standard. Our SEER2 explained guide breaks down what those numbers mean for a home in a hot inland climate like Ontario or Fontana. If you are replacing a 12-SEER unit from the 2000s, a modern R-454B system can meaningfully cut the cooling portion of your bill during a triple-digit Inland Empire July.

Can I add R-454B to my existing R-410A system?

No — and this is the single most important thing to understand. You cannot add R-454B or R-32 to an R-410A air conditioner. The refrigerants operate at different pressures and require different components, lubricating oils, and safety hardware. Switching refrigerant is not a top-off; it means installing a new, factory-matched system designed for the new refrigerant.

If a salesperson offers to "convert" your old unit to R-454B, that is a red flag. A correct low-GWP upgrade replaces the outdoor condenser and the matched indoor coil together, sized for your Inland Empire home, with the line set and metering device evaluated for compatibility. Matched systems are also how you keep the manufacturer warranty valid and hit the efficiency rating on the label — mismatched parts can quietly cost you both.

Do I have to replace my R-410A system now?

No. If your current R-410A system runs well, keep it. R-410A is still legal to buy and use to service existing units, so a technician can recharge and repair your older system while supply lasts. The rule changed what is installed in new equipment — it did not outlaw the AC you already own, and there is no requirement to rip out a working system. For most Inland Empire homeowners, the smart move is routine maintenance plus a clear-eyed plan for when the unit reaches the end of its life.

That said, there is a cost trend worth planning for. As HFC production quotas decline, virgin R-410A prices are expected to rise, and reclaimed R-410A becomes more important for servicing older units. If you are already weighing repairs against a new system, read our breakdown of AC repair vs replace in 2026 and the signs you need a new AC system.

The bottom line for California homeowners

In 2026, a new central AC or heat pump in California almost certainly runs on R-454B (or R-32 for mini-splits), not R-410A. It is federal policy under the AIM Act, reinforced by California's own refrigerant management program. The refrigerant is lower-GWP and A2L, the equipment is built with modern leak-detection safety, and you do not need to panic about the system you already own. The practical summary is simple: keep and service a healthy R-410A unit, but plan a matched R-454B upgrade once it passes 10 years or faces a major repair. When it is time to upgrade, choose a properly matched R-454B system and a contractor who installs to code. For local pricing context, see our AC replacement cost in California for 2026 guide or plan an AC replacement with us.