R-410A vs R-454B/R-32: What Homeowners Need to Know in 2026

What Changed on January 1, 2025

Under the AIM Act (American Innovation and Manufacturing Act of 2020), new residential and light commercial HVAC equipment manufactured after January 1, 2025 must use refrigerants with a global warming potential (GWP) below 700. This regulation phased out R-410A (GWP: 2,088) — the workhorse refrigerant used in virtually every heat pump and air conditioner sold in the United States since the early 2000s.

The two primary replacement refrigerants are R-454B (GWP: 466), adopted by manufacturers including Carrier, Daikin, Bosch, and Lennox, and R-32 (GWP: 675), adopted by Mitsubishi, Fujitsu, and some Daikin product lines. Both are classified as A2L refrigerants — “mildly flammable” — a change from R-410A's A1 non-flammable classification.

For homeowners purchasing a heat pump in 2026, this transition is already complete. Every new unit you can buy uses one of these newer refrigerants. The question is not whether you will get a low-GWP refrigerant — you will. The question is what you need to know about the practical differences.

Detailed Refrigerant Comparison

Understanding GWP Regulations and Timeline

The AIM Act established a phasedown schedule for hydrofluorocarbon (HFC) refrigerants, targeting an 85% reduction in HFC production and consumption by 2036. The January 2025 equipment manufacturing deadline was the first major milestone for residential HVAC. Here is the complete timeline homeowners should understand:

• January 1, 2025: New residential and light commercial HVAC equipment must use refrigerants with GWP below 700. R-410A equipment can no longer be manufactured.
• 2025-2026: Transition period. Some distributors still have R-410A inventory from 2024 manufacturing. These units can still be sold and installed legally.
• 2026 and beyond: R-410A supply for servicing existing systems remains available. Prices may increase gradually as production decreases under the phasedown schedule.
• 2030-2036: Further HFC production reductions. R-410A service refrigerant will become more expensive. Reclaimed refrigerant will fill some supply gaps.

This timeline is similar in structure to the Foreign Entity of Concern (FEOC) provisions affecting solar equipment — both involve phased transitions with specific compliance deadlines. The key difference is that the refrigerant transition is already past its main deadline, while FEOC compliance for solar takes effect July 4, 2026.

Is A2L Safe for Your Home?

The shift from A1 (non-flammable) to A2L (mildly flammable) refrigerants is the change that generates the most concern among homeowners. Here is what the classification actually means and why the safety risk is extremely low.

A2L means “mildly flammable with low burning velocity.” Unlike propane (A3) or butane, which ignite easily from a spark or match, A2L refrigerants require three simultaneous conditions to burn: a concentration of refrigerant in the 13-23% range, an ignition source with energy above 5,000 millijoules (a standard spark is about 0.5 millijoules), and a confined space with no ventilation. In practice, these conditions are nearly impossible to achieve in a residential installation.

Modern equipment includes additional safety features specifically for A2L refrigerants: integrated leak detection sensors that shut down the system if refrigerant concentration reaches 25% of the lower flammability limit, updated electrical components rated for A2L environments, and refrigerant charge limits based on room size calculations per ASHRAE 15.2. Your installer will verify that room sizes meet the minimum requirements during installation.

Impact on Cold-Climate Performance

For New England homeowners, the efficiency gains from R-454B and R-32 are particularly relevant. Both refrigerants offer improved thermodynamic properties at low ambient temperatures, meaning your heat pump produces more heat per kilowatt of electricity consumed during the coldest winter hours — exactly when efficiency matters most.

R-32 is especially noteworthy for cold climates. Its higher discharge temperature capability allows heat pumps to deliver hotter supply air at low outdoor temperatures. The Mitsubishi Hyper-Heat units using R-32 can deliver 120°F supply air even at 5°F outdoor temperature, compared to 105-110°F with the previous R-410A models. This makes a noticeable difference in comfort for homes with ductwork designed for higher-temperature furnaces.

What Homeowners Need to Know in 2026

Here is a practical summary of what the refrigerant transition means for your heat pump purchase decision:

• If buying new in 2026, you automatically get R-454B or R-32. You do not need to specifically request a low-GWP refrigerant. All new equipment uses one of these.
• Existing R-410A systems can still be serviced. Refrigerant remains available for maintenance and repairs. Do not feel pressured to replace a working R-410A system solely because of the refrigerant transition.
• You cannot retrofit an R-410A system to R-454B. The refrigerants operate at different pressures and require different lubricant oils. Mixing or swapping is not possible.
• Equipment costs have not significantly changed. Despite early concerns about price increases, the refrigerant transition has not materially affected heat pump pricing. Manufacturing scale has ramped up quickly.
• New refrigerants are 5-8% more efficient. Over 15-20 years of equipment life, this efficiency improvement saves $800-$1,500 in electricity costs at New England rates.
• Installer certification matters. EPA Section 608 certification has been updated for A2L handling. Verify that your installer has completed A2L training. All NuWatt technicians are A2L certified.

Common Myths About the Refrigerant Transition

• “R-410A will be banned and I won't be able to service my system.” — False. R-410A production continues under the phasedown schedule. Service refrigerant will be available for decades. Prices may increase modestly but your existing system will not be stranded.
• “A2L refrigerants are a fire hazard.” — False. Over 200 million A2L units are in use globally with zero fire incidents from the refrigerant. The “mildly flammable” label describes laboratory conditions, not real-world risk.
• “I should buy an R-410A system now before they're all gone.” — Poor advice. R-454B and R-32 systems are more efficient, use less refrigerant charge, and will have better long-term service support. There is no advantage to buying obsolete technology.
• “New refrigerants don't work in cold climates.” — False. R-32 actually performs better in cold climates than R-410A, with higher heat output at low temperatures. Mitsubishi's latest Hyper-Heat models with R-32 are the best-performing cold-climate heat pumps available.

If You Already Have an R-410A System

If your current heat pump or air conditioner uses R-410A, there is no reason to replace it prematurely. R-410A refrigerant will remain available for service and repairs for the foreseeable future. The AIM Act restricts manufacturing of new R-410A equipment, not the refrigerant itself. Reclamation and recycling programs ensure a continued supply chain for service needs.

However, when your R-410A system reaches end of life (typically 15-20 years for heat pumps), your replacement will automatically be R-454B or R-32. At that point, you cannot reuse any existing refrigerant lines without thorough flushing, as the oils are incompatible. Plan for a full system replacement — indoor and outdoor components — when the time comes.

For homeowners with R-410A systems that are 10+ years old and experiencing frequent repairs, upgrading now to a new R-454B or R-32 system makes financial sense. The 5-8% efficiency improvement alone saves $150-$250 per year at New England electricity rates, and you gain access to current state rebate programs that may not be available when your old system finally fails. Timing a planned replacement is almost always better than an emergency replacement in the middle of January.