> What refrigerants are you considering as there is more environmental stuff coming out killing 410A.
I'm also interested in this. Specifically, I'm interested in R-744 (CO2) as it has a GWP (global warming potential) of only 1. R-32 (Difluoromethane) has a GWP of 675 while R-410A has a GWP of 2088. Japan has had R-744 heat pumps for years now.
Drawdown lists refrigeration improvements as the single most effective method (we need to do all of them) for combatting climate change.