I purchased new furnace last winter, but did not have the AC done because it still works. So basically my hvac system is a loveable mutt -- new Trane furnace and an old Carrier AC. The new furnace is covered under the 10 year warranty.

Eventually I will get the AC replaced, and will likely get a Trane. My question is, how will the warranty(s) work? I assume I will have two -- one for the furnace, and one for the AC. Also, if the AC install is done by a different company, will they have to do the warranty work on the AC, while the furnace install company has to do the furnace work?