depending on the age of your current AC, consider replacing it just before the new mandates go into effect with a current one. I get about 20 years out of my AC units in Texas, but you need to service the unit regularly. 15 to 20 years will get you down the road a long way.
I have similar concerns about water heaters and AC's. So I will be buying a new H2O heater to storage for the future.
See my post on the Water Heater:
https://freerepublic.com/focus/f-chat/4202162/posts Note: I live in a new community, therefore the system is not old and have caught it before much damage is done.
With older systems, much less would be realized, just as with the water heaters. See link attached.