R410A vs R454B: Heat Pump Refrigerant Change in Maine

Editor's note (March 2026): The federal 25C tax credit referenced in this article expired December 31, 2025. Efficiency Maine rebates remain available and are now the primary incentive for heat pump projects. Learn more about what has changed.

We have been getting calls from customers in the Portland area this summer asking the same question: "I heard they changed the refrigerant in heat pumps. Does that affect my system?" Short answer: no. Your system is fine. But the longer answer is worth understanding, because the change is real and it does affect new installations going forward.

What Changed on January 1, 2025

The EPA now requires all new residential heat pump and air conditioning equipment to use refrigerants with a lower Global Warming Potential (GWP). This is part of the American Innovation and Manufacturing (AIM) Act. In practice, it means the industry is moving from R410A (the refrigerant in most systems installed over the past 15 years) to R454B, which is classified as an A2L refrigerant.

R454B has about 78% lower GWP than R410A. Same heating and cooling performance. Lower environmental impact.

If Your System Was Installed Before Summer 2025

Your system uses R410A. This is true for every heat pump we installed before summer 2025, because R454B equipment only became available through our Mitsubishi distribution channels in early summer 2025. Before that, we were installing the best available technology that met all safety, efficiency, and Efficiency Maine program standards.

Your R410A system will continue to run for its full expected lifespan. There is nothing to replace, nothing to upgrade, and nothing to worry about.

The Questions We Keep Hearing

Will my R410A system still work?

Yes. Your R410A system will operate the same way it has since the day we installed it. R410A refrigerant will remain available for service and repairs for many years. The EPA phase-down targets production of new equipment, not servicing of existing systems.

Can I add a new indoor unit to my R410A multi-zone system?

Editor's note (December 2025): Most R410A indoor unit inventory has now been depleted. Parts remain available for servicing existing systems, but new R410A equipment is no longer generally available through distribution channels. If you need to expand your system, contact us to discuss your options.

At the time of writing, R410A compatible indoor units were still available through existing inventory. The new unit must be R410A compatible to work with your existing outdoor unit. If you are considering expanding your system, give us a call and we will walk through your options.

What if my R410A system needs refrigerant or repairs?

R410A refrigerant will be available for servicing existing systems through at least 2035, and likely longer. Parts and components for R410A systems will continue to be manufactured and stocked throughout your system's lifetime. We maintain inventory for all the systems we have installed.

Schedule a free energy assessment if you are considering expanding your current system or adding heat pumps to additional rooms.

Why did Horizon Homes not install R454B equipment earlier?

Because it was not available. R454B mini-split equipment only became accessible through our distribution channels in early summer 2025. We install the most current, compliant, and reliable technology available at the time of each installation. Every system we put in met all applicable standards on the day it was installed.

Is R454B better than R410A?

Both refrigerants deliver the same heating and cooling performance. R454B has a lower environmental impact (lower GWP), which is why the industry is transitioning. R410A systems have a proven track record over two decades of reliable operation. The efficiency of your system depends more on equipment quality and installation than refrigerant type. As a Mitsubishi Diamond Contractor, we install to the highest standards regardless of refrigerant.

Should I replace my R410A system with R454B?

No. Not unless your system has reached the end of its useful life, which is typically 15 to 20 years. Your R410A system remains fully functional, serviceable, and efficient. When it is eventually time for replacement, we will install the latest available technology.

What This Means for New Installations

If you are getting a heat pump installed today, your system will use R454B refrigerant. The performance is the same. The installation process is the same. The Efficiency Maine rebates are the same (up to $9,000 for qualifying households). The federal 25C tax credit also applies to both R410A and R454B systems, covering 30% of equipment and installation costs up to $2,000 per year for qualifying heat pumps. The only difference is the refrigerant inside the system, and that difference benefits the environment.

Our technicians are trained and certified in both R410A and R454B (A2L) refrigerants. We service every system we have installed, regardless of refrigerant type.

The Bottom Line

If you have an existing R410A heat pump: it works, it will keep working, and we can service it for years to come.

If you are getting a new system: you will get R454B, which performs the same and has a lower environmental footprint.

Either way, we are here. If you have questions about your specific system, call us at (207) 221-3221. If you are thinking about adding heat pumps to your home, schedule a free energy assessment and we will walk through your home and show you what makes sense.