(I don't know what circa means; I'll have to look it up)
Is this not a-MA-zing? We have two A/C units, one for each end of the house. They are original to the house and still going strong. Of course, they aren't very energy efficient and we're contemplating replacing them. Tom did some research (thank you internet and all those people who love to put their information out there) and discovered that if we replaced them with new ones, we'd save about $200.00 a month on our electric bill. You can't beat that with a stick.