There are thermal breakers, which are the most common and least expensive type, and magnetic (aka "Magneto-mumble-mumble-thing-or-other") breakers, which are more expensive and longer lasting. I'd go for the latter.
You might want to run eyes & hands over the entire AC system though, and make sure ALL of it is adequately sized and showing no heat damage, fraying, etc. Even if the PO starched his socks, you don't know what he might have done to the AC system. Good time to check for a newfangled concept
like a proper GFI in the system, too.