If your heat pump went in before the federal refrigerant transition, it most likely runs on R-410A; new residential systems use lower global-warming-potential A2L refrigerants such as R-454B or R-32. The two can’t be mixed, so a replacement means a new matched indoor and outdoor pair, plus a decision on the line set. At Perennial DC Heat Pumps we replace ducted heat pumps across Washington, DC, and our estimate names the refrigerant and matched models.
Which refrigerant is in your system now?
Look at the outdoor unit’s nameplate. It states the refrigerant type and factory charge, and you can read it from where you normally stand, without opening anything. That’s enough to tell an R-410A system from an older R-22 one.
The U.S. EPA’s Technology Transitions rule under the AIM Act moved new residential split systems away from R-410A toward lower-impact refrigerants. Manufacturers answered mainly with R-454B and R-32, both classed A2L under ASHRAE Standard 34: lower toxicity and lower flammability. Our replacement page explains why that change usually turns a one-part repair into a matched-system replacement.
Can you keep your indoor unit and just swap the outdoor one?
Usually not. An R-454B outdoor unit needs an indoor coil designed for R-454B, with the right metering device and, on many models, a refrigerant leak sensor wired to the controls. The pair must appear together on an AHRI certificate, which lists the rated capacity and efficiency of that exact combination. DCSEU asks for that certificate, as our rebate guide explains.
An existing R-410A coil can’t simply be reused with a new A2L outdoor unit, even when the copper fittings line up. For an air-handler replacement where your newer outdoor unit stays, the new indoor unit has to be listed with that outdoor model. When no listed match exists, we’ll tell you straight that a full matched replacement is the real comparison.
Can the old copper lines stay in your walls?
Sometimes. The line set is the pair of copper tubes between the indoor and outdoor units. Whether we can reuse it depends on four things: the diameters the new equipment calls for, the total length and lift, the tubing’s condition, and contamination from the old system’s oil or a past compressor failure. The manufacturer’s instructions set the size and length limits.
A line set running through finished ceilings in a rowhouse, or through a shared chase in a condo, can be worth keeping if it passes, because replacing it means opening walls. Our estimate states the reuse assumption, the test that confirms it, and the price and approval step if it fails.
Put these questions into a project brief
Describe what you know about the property. Technical unknowns can stay unknown.
Are the new refrigerants safe in your home?
Yes, when they’re installed to the rules that came with them. The UL 60335-2-40 safety standard sets charge limits relative to room size, and many A2L air handlers carry a leak-detection sensor that starts the blower to disperse refrigerant if it senses a leak. That sensor has to be wired and tested, never bypassed.
The refrigerant work follows a fixed order. EPA rules require a Section 608 certified technician to recover the old charge; the new circuit is brazed under nitrogen, pressure-tested with nitrogen to find leaks, evacuated with a vacuum pump to the micron level the manufacturer specifies, then charged by weight and verified by the method in the instructions. Our quote checklist lists each step as its own record.
What should your estimate say about refrigerant?
Our written estimate names the indoor and outdoor model numbers, the refrigerant, the AHRI certificate number, the line-set decision, any leak-sensor wiring and how startup is recorded. Wording such as “recharge as needed” or “new gas added” describes neither the equipment nor the work.
Our cost guide treats an accessible, reusable line set and a hidden run that must be replaced as different jobs. Replacing a line set through finished space adds opening and patching that a basic equipment line doesn’t show, so we price it from the site visit, or price the test that decides it.
What records should you keep afterward?
Keep the model and serial numbers, refrigerant type and total charge, AHRI certificate, pressure-test and evacuation readings, and the manuals together; we hand them over at the end of the job. A future technician needs that record to service an A2L system properly; the brand on the thermostat doesn’t tell them enough.
Our buying guide puts refrigerant alongside sizing, ducts and electrical work. For a replacement estimate, send us a photo of the outdoor unit’s nameplate showing the refrigerant and model number, plus any recent service report.
Questions before you decide
Can a new refrigerant simply be added to an older system?
No. An R-410A system can't be converted to R-454B or R-32 by changing the refrigerant; the compressor, metering device, controls and safety parts are designed for one refrigerant. Under EPA rules a Section 608 certified technician recovers the old charge, and the new system is charged with its own.
Does a reusable line set mean the indoor coil is compatible?
No. The line set is copper tubing, judged on size, length, condition and cleanliness. Your indoor coil must be listed with the outdoor unit on one AHRI certificate and designed for the same refrigerant, so a reusable line set tells us nothing about the coil.
Why should the refrigerant appear in the proposal?
It identifies the matched equipment pair, the safety parts an A2L system needs, and the line-set decision. It also tells any future technician what's in your system, and the AHRI certificate DCSEU asks for depends on the exact matched models, so our written estimate names it.