...snip.... Freon-based air conditioners are history. ...snip...
That's news to ME - every AC I've seen use Freon or other brand refrigerant. Now if you said "Freon (tm) R-12 refrigerant based ACs are history", I'd say "yes, and Dad should have sold his 70 lbs of Freon when he could" R12 was basically replaced with R134a
R-22 is the next phase out
BTW "Freon" is a trademark of Dupont, not that everyone doesn't use it, or the term "gas" - for instance, F-22 is Dupont's refrigerant, while the generic term is R-22