R-454B (trade names Opteon XL41, Puron Advance) is an HFO/HFC blend refrigerant introduced as a primary replacement for R-410A in residential AC and heat pump systems starting January 2025. Its GWP is about 466 — roughly 78% lower than R-410A.
Performance-wise R-454B is nearly identical to R-410A: same SEER2 ratings achievable, similar operating pressures, equivalent cooling and heating capacity per pound. Homeowners would not notice a performance difference between an R-410A and R-454B system of the same efficiency tier.
R-454B is classified A2L — mildly flammable under specific lab conditions. In residential installation it requires no special handling vs R-410A; A2L flammability requires sustained open flame in concentrated refrigerant vapor, which doesn't occur in a properly installed system.
R-454B and R-410A are not interchangeable. A condenser charged with one will not work with a coil designed for the other — different oils, different pressures.
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