a new refrigerant will be out soon on the market. it will be standard refrigerant for general motors cars and trucks starting 2013. it is more earth friendly than the R134a since it breaks down in the atmosphere in less than 48 hours the manufacturers say compared to R134a that breaks down in months if not years. retrofitting is not necessary for present R134a systems, just retool the a/c shop with new infrared leak detector since R1234yf is slightly flammable