I'm in the process of buying a house, and the heat pump is a 17 y/o Trane which appears to be working fine (AC at least...its nice and cold). I'm hoping it'll last another 5-6 years.

The air-handler however is 27 years old and is rusted and damaged as you can see in the picture linked below.

http://www.flickr.com/photos/2776004...87196/sizes/o/

How important is it to match a new air handler to the Trane I have in place now? If they use whatever builder grade unit they find and it's not matched, what will be the result for me? Higher electric bills? The Trane will die sooner? Since the current 27 y/o handler is original, it doesn't appear to be matched to the 17 y/o Trane...and it seems to be working fine.

Secondly do the pictures of those ducts look pretty bad? Should I assume they are leaking or something? The inspector is recommending that they be replaced.

Also portions of the newer ducts are touching the ground in the crawlspace. Is it a pretty big deal that they aren't hung properly? I'm assuming it is since my inspector said something about water accumulating in them if they dip to the ground.

Thanks for any info. I'm pretty new to all this.