I need to recharge my ac system, but the cost of R-22 is so high these days. Does anyone know if it's possible to put 410-A into an R-22 system?

the rubber seals used for r-22 are not compatable with 410A, you would be further ahead to find where your leaks are and fix them. Once the system is tight you shouldn't have to recharge it.
My home system is 15 years old and my car, 10 years neither has ever been recharged. ( maybe I should keep my mouth shut ! )

did you know the federal fine for discharging refrigerant into the air is $5000, and up to 5 years in prison?

not a DIY job. the recovery equipment is $10-25,000 to purchase.

other major surprises: the refrigerant oil in a 1st-generation a/c turns to sludge when the new refrigerants hit it, which burns up the compressor. the whole thing has to be flushed with dry nitrogen and then prepared for recharge.

the new stuff is not as efficient... you need new evap and control valves in the lines, the filter/drier needs to be replaced, and the A-coil and possibly the evaporator are not sized correctly for the new stuff, so you get crummy cooling even if everything else is done right.

if you think this sounds like a total replacement, you're catching on.

by a pro who has the equipment, the training, and the EPA license.

in our area, there is at least one HVAC shop that's offering 2-1/4 ton replacements for $1800... this is probably a SEER 14, low end, but it cools and it's repairable.

ain't the news you're looking for, but really, it's what you need to hear. get quotes.

Good info all around. I was aware that we'd have to somehow capture the old refrigerant if any remained. I would definitely hire someone to do it. But I wouldn't be above managing what I could if I could.