When 2010 arrives and R22 systems are no longer sold, the price of R22 will go out of sight. Will it be possible to convert and R22 system to Puron?

R-22 will not go out that quick, and no if you want 410 you will need a new unit.

The R-22 apocalypse some are predictions doesn't seem likely due to stockpiles of fresh R-22, R-22 recycling and R-22 drop in replacements. Because the oils used with R-22 and 410A are incompatible as we know it now, conversion isn't an option.

If you check the Department of Energy site you will find that although all NEW systems will have to use 410A they will still be PRODUCING R22 for existing systems for another ten years. I have already had one contractor try to sell me a new system by telling me that R22 for my existing system would not be available after January 2010. He became very quiet once I quoted the Department of Energy.