At a glance
| R-410A | R-454B | |
|---|---|---|
| Composition (by weight) | R-32 / R-125, 50 / 50 | R-32 / R-1234yf, 68.9 / 31.1 |
| ASHRAE 34 safety class | A1 | A2L |
| GWP, 100-year (EPA Technology Transitions table) | 2,088 | 465 |
| Glide at a 40°F dew point | 0.2°F | 2.4°F |
| Critical temperature | 160.4°F | 173.5°F |
| Lubricant | POE | POE |
| EPA SNAP listing, home and light-commercial AC | Acceptable, new equipment | Acceptable subject to use conditions, new equipment |
Chemours sells R-454B as Opteon XL41, and Honeywell's technical data sheet lists it as Solstice 454B. EPA's Technology Transitions reference table lists R-454B's GWP as 465; Chemours and Honeywell list 466 on the IPCC AR4 basis.
Operating pressures
R-454B was designed to run close to R-410A, a little lower. At a 40°F evaporator, R-410A reads 118.4 psig and R-454B 107.0 psig (dew points). At a 110°F condensing temperature, R-410A reads 366.4 psig and R-454B 345.9 psig (bubble points). Chemours' own cycle comparison for air conditioning puts R-454B suction and discharge pressures about 7% below R-410A.
Close is not the same. An R-454B suction reading of 107.0 psig is a 40°F dew point, but on an R-410A chart that pressure reads 34.8°F, so using the wrong chart overstates superheat by several degrees. Set gauges to R-454B and use its own PT chart.
Glide and charging
Arkema describes R-410A as a near-azeotropic mixture, and its glide is almost zero. Arkema puts R-454B's glide at about 1.2 K (about 2°F), so its chart has separate bubble and dew columns: use the dew point for superheat and the bubble point for subcooling (see bubble point, dew point and glide). Arkema advises charging R-454B as liquid because it is a blend. Chemours says R-454B's glide is low enough that a system can be topped off after a leak; Daikin's literature takes the opposite view for blends. Follow the equipment manufacturer's service instructions.
Safety class and equipment
AHRI's summary of ASHRAE 34 lists R-410A as A1 (lower toxicity, no flame propagation) and R-454B as A2L (lower toxicity, lower flammability, with a maximum burning velocity of 10 cm/s or less). EPA lists R-454B as acceptable for new residential and light-commercial AC and heat pumps subject to use conditions, which require the equipment to meet UL 60335-2-40, 3rd edition. UL's summary of that edition says systems above a charge limit, typically more than 4 lb, need a refrigerant leak detector that starts the indoor fan to dilute a leak. See A2L refrigerants for what changes in tools and handling.
Cylinders differ too. AHRI Guideline N calls for all refrigerant containers to be light green-gray (RAL 7044) since 2020, with a red band on the shoulder or top for flammable refrigerants. Arkema notes that most cylinders of any refrigerant will be gray, so color alone no longer identifies R-410A. A2L cylinders such as R-454B use a left-hand thread on the valve outlet, per Arkema and Chemours.
Not interchangeable
R-454B is not a retrofit refrigerant for R-410A equipment. EPA lists it for new equipment only, Carrier states that R-454B "cannot be used as a direct replacement for R-410A in an existing system", and Arkema notes that R-410A systems lack the safety features A2L refrigerants require. An R-410A system is serviced with R-410A; an R-454B system with R-454B.
US regulatory status
EPA's 2023 Technology Transitions rule under the AIM Act set a GWP limit of 700 for refrigerants in new residential and light-commercial AC and heat pump systems starting January 1, 2025. R-410A is above that limit; R-454B is below it. An interim rule let systems built from components made or imported before 2025 be installed until January 1, 2026.
A final rule published May 26, 2026 and effective July 27, 2026 removed that installation deadline. New R-410A systems may still be installed where every specified component was manufactured in or imported into the US before January 1, 2025. New systems using R-410A components made after that date remain prohibited, and such components must be labeled "For servicing existing equipment only." EPA declined to treat a replacement condensing unit on an existing split system as a new installation, so a homeowner can still replace just a failed condensing unit. EPA says components used to repair existing systems are not subject to the restrictions, though the AIM Act phases HFC production and consumption down to 15% of baseline by 2036.