The difference in efficiency is actually less than 5% for r32 compared to 410a. The offshoot of that is also that the compressors will not last as long because they run like 20f hotter. The 4%ish efficiency gain is also not enough alone to meet the new requirements, so it still falls back to a larger surface area needed on the A coil. The efficiency standards that were being put in place are simply too big of a jump in too short an amount of time. It’s not like everyone doesnt already want to save money on their heating and cooling costs, but requiring homes already built to deal with the fallout of having to install units that won’t fit in their homes is a shit move. I don’t have anywhere I could even take away from to make my utility closet any larger. Requiring the new standards in newly built homes wouldn’t be as big a deal, as it can be planned and built for, but some people will have to buy used hvac units, keep their current ones running as replacement costs shoot sky high (working control boards for some old units can fetch $800. Same issue with other parts and labor to keep them running), or give up and install window units that are way, way, less efficient.