R-454B explained

What the manufacturer says it is

Chemours sells R-454B as Opteon XL41. The product information sheet lists it as a blend of R-32 and R-1234yf, 68.9 percent and 31.1 percent by weight. Ozone depletion potential is 0. Global warming potential is 466 on the AR4 basis and 467 on AR5. The safety classification is A2L. The lower flammability limit is 11.5 percent by volume, cited to ASHRAE Standard 34. Chemours describes it as a mildly flammable, low-GWP refrigerant “to replace R-410A in new equipment designs,” including heat pumps. The product page states a GWP of 466 and calls that a 78 percent reduction versus R-410A. Product information PDF Product page

“New equipment” is the important phrase. Rheem Canada’s A2L FAQ says A2L refrigerants can only be used in equipment designed for A2L refrigerants, and that Rheem has chosen R-454B as its primary refrigerant. Rheem FAQ Pouring R-454B into a system built for R-410A is not a service procedure. The compressor, the oil, and the safety hardware are part of the equipment design.

Why new machines are showing up with it

Canada ratified the Kigali Amendment on November 3, 2017, and implements the HFC phase-down through the Ozone-depleting Substances and Halocarbon Alternatives Regulations. Canada.ca Environment and Climate Change Canada’s consultation document sets the consumption cap at 10 percent below baseline from 2019, 40 percent from January 1, 2024, 70 percent from January 1, 2029, and 85 percent from January 1, 2036. ECCC That is a cap on how much HFC can be consumed. It is not, in that document, a sentence that makes an installed R-410A heat pump illegal.

Manufacturers that sell into more than one country have moved new residential equipment to R-32 or R-454B. The FIT Aurora outdoor family on the capacity page, DH9VS, is R-32. The Aurora wall matches in the same catalog are also R-32. Atmosphera, a different wall family, is R-32 too. Daikin catalog, CT-ZONE 02-26 Moovair’s February 2026 single-zone, Central-Moov, and Myriad+ tables print R-454B for the matches on the capacity page. M-Series Mitsubishi Electric Canada’s current Hyper-Heat page, cited only as another maker’s choice, says that lineup includes R-454B models. Mitsubishi Electric Canada Which fluid is in the quoted model is the brand’s choice. NRCan’s cold-climate listing rules score HSPF2, SEER2, capacity at −15°C, COP, and compressor type. They do not name a refrigerant. NRCan Yukon’s rebate follows that list, the balance point, and the backup. It does not pay extra for R-454B.

What a homeowner needs to know about safety

A2L, in the classification Chemours prints, means lower toxicity and mild flammability. It is not the non-flammable A1 class R-410A sits in, and it is not propane. The charge limits, leak sensors, and service tools belong to the equipment and the technician. None of that is a Saturday job.

• Do not vent refrigerant. A release is a regulated waste, not a step in cleaning the coil.
• Do not “top up” an R-410A system with R-454B, or the reverse. Rheem’s line is the useful one: A2L refrigerant only in equipment designed for it.
• Ask which refrigerant the quoted model uses, and whether the installer is set up for that class. The nameplate is the record. The brochure family name is not.
• An existing R-410A heat pump can keep running. The supply of new high-GWP refrigerant is what the phase-down tightens. That is a different sentence from “your system is illegal.”