Speaking of refrigerants, you can replace R22 directly, R134 sometimes directly but desirably with new oil and capillary, and probably other refrigerants with..

Speaking of refrigerants, you can replace R22 directly, R134 sometimes directly but desirably with new oil and capillary, and probably other refrigerants with... R290 - an innovative compound that is very environmentally friendly and cheap. Also known as Propane. I've done it with my home office room A/C, a small 12,000 BTU unit. I couldn't believe it when I found out you can do that. They say R290 is cleaner, purer, blah blah, but the gas from a simple propane tank you can get anywhere works fine. Remains to be seen for how long, so far 2 summers and going strong.