When to replace Centrail air units?
 

What's the normal age of most central air units? I had to service mine and it's at about 12 years old now with a SEER rating of 10.

I just had to replace mine. Mine is 17 years old. The people that installed the new one told me that 15-18 years is a pretty average lifespan for those things.

If you don't mind sharing, about how long did it take them to replace the old and install the new? Total job cost?

Ours conked out last summer - its 18 yrs old. The furnace is 27 yrs old and also near the end of its life cycle ... so we're hoping to replace both at the same time and get some sort of pkg. discount.

What do you mean by a SEER rating? Generally you replace them when they break, which is unfortunately during summer. I had one for 6 years and another for 2. Units are given alot of use here, and they are ran for 5 months straight during summer. About 3k for the unit