There are HFC refrigerants to replace R-22 in any application. (NU-22 from ICOR is one) You will not have a problem with availability of refrigerant for a system you buy today.
Originally posted by cde72
There is no retrofit drop in refrigerant for HCFC-22 and as far as I know, none in research. To cross your fingers and hope that someone develops it is a waste of time. I have used RX-11 flush and it does a sufficient job to warrant using the lineset for HFC-410a. HFC-410a does have different operating pressures, is hygroscopic compared to HCFC-22, and operates with a different oil, but not much else is different. To make an informed decision, you really need to know that while HCFC-22 is being phased out just like all the HCFC's and the CFC refrigerants before it, HFC-410a is just a stop gap, it satisfies the requirement of zero ozone depletion, but it still has a global warming potential, and it has a questionable history of reliability due to installer ignorance. People don't like change, and HVAC techs REALLY don't like change. If it were my condo and I was going to be there for the next 20 years, HFC-410a would be my choice, probably with Carrier. If I were going to sell it in 5 years, I'd probably still choose HFC-410a, if I was selling it next year, then I would go with HCFC-22.
Just my two cents.