Today's refrigerants aren't the final stop. Here's what's realistically next, why propane isn't a simple swap-in under current US codes, and why there's no confirmed date yet.
As explained in the AIM Act article, the federal allowance pool for HFC refrigerants keeps shrinking on a fixed schedule — including R-32 and R-454B themselves, which are HFCs with meaningfully lower GWP than R-410A (675 and 466 vs. R-410A's 2,088) but are not zero. The honest expectation, shared across refrigerant manufacturers, is that today's "new" refrigerants are a waypoint, not a final destination — another transition is coming, just not on a firm calendar yet.
Unlike the 2025 shift to R-32/R-454B, which had a clear regulatory trigger and a known replacement lined up years in advance, the next step is genuinely unsettled as of this writing:
The AIM Act's allowance pool steps down again in 2029 (see the AIM Act article), which is the most concrete forcing function on the horizon — but a shrinking allowance pool doesn't by itself mandate a new refrigerant chemistry the way the 2025 GWP threshold did. It's reasonable to expect pressure building toward another transition sometime around 2030 and after, but treat that as an informed expectation, not a scheduled rule — nobody in the industry has a locked date yet.
A system installed today running R-32 or R-454B isn't going to be forced out of service by a future refrigerant transition — the pattern with R-22 and R-410A has been "keep servicing what's out there, restrict what's new," not "existing equipment must be swapped." The practical risk is the same one that applies to R-410A right now: whichever refrigerant your system uses, it's a smaller and smaller share of an evolving supply for as long as it's in service, so future repairs involving refrigerant may cost more over time.
For an aging system that's already a marginal repair-vs-replace call, that's one more reason it may make sense to replace before you're forced to by a breakdown, rather than after — you get to choose the timing and the equipment, instead of reacting under pressure with whatever's on the truck.
HVAC Referee checks your actual quote against equipment, installation, and pricing standards — including which refrigerant and efficiency tier you're being quoted.