I've got zoned heating in a 1950's modified cape code with two Trane heat pump/air handler units that are from 1992 - one is 10 seer, the other 11. Total SF is 1650. I'm looking to replace the 11 that heats/cools the front of the house. I might add on to the back - that's why I'm thinking of waiting to replace that one.
Do I need to replace the air handler? What about the duct work - it's the round 6 inch flexible stuff? The air handler is in an outside utility shed and the ducts run through a tight crawl space, maybe 2 feet.
I was looking at the Trane XL20i or the XL16i. Would the cost difference be made up quickly with the higher efficiency?
I also see that Trane has a smaller air handler for tight spaces (2/4TFB Compact) - any reason not to get this?
Any general comments on Trane versus other manufacturers?