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Hello,

My wife and I recently (september) purchased a 44 year old home in Indianapolis IN. Prior to having the home listed, the previous owner had a pre-listing home inspection in Feb 2012 where the inspector noted a six-degree temperature difference between the rest of the house and a southern wing to the house. This wing is part of the original house, is one story, has about R44 attic insulation (we had it re-insulated upon moving in) and has three rooms: an office/den, a guest master bedroom with 4-piece ensuite bath, and another full bath. This wing is over a crawl space, which has no exterior wall crawlspace vents. However, due to storage equipment blocking the access to the crawlspace, it was never actually inspected. The original owner had her heating company evaluate the temperature difference, and they recommended a zone heating system.

Based on this information, I had a couple companies come by to give quotes on the attic insulation and zone system installation shortly after we moved in. By this point, of course, the crawl space access panels were unobstructed and we discovered that the ducts leading from the main supply trunk to those rooms in that wing had actually fallen apart. So, we figured re-connecting the ducts would solve the problem.

However, it did not. In the interim, my parents visited and my father suggested insulating the ducts themselves. My heating company did so and in the process found another duct in that crawl space which had actually been disconnected. However, despite that, there is still quite a bit of difference in temperature, sometimes ten degrees when it is exceedingly cold outside.

I have had several companies come in and offer contradictory suggestions on how to fix the problem, so I am looking for additional advice.

One major theme involves encapsulating the crawl space with insulation of the band boards. Most companies who offer that service CAN also install 4" foam board insulation along the concrete walls but recommend against this, as its cost savings are minimal without several years' worth of deep freezes. Of those who recommend band board insulation, some recommend foam board, some foam board with spray foam to anchor the edges, and some batt insulation.

Other companies recommend pulling off the insulation on our subfloor, pulling off the insulation we just installed on the ductwork, and adding a supply vent to heat the crawl space, with reinforcement of the band board insulation.

We don't really have a moisture problem at all, the crawl space is bone dry even when it is pouring rain outside, so with a 12 or even 20 mil piece of plastic encapsulating the crawl space I can't imagine it offers much in the way of insulating value. Furthermore, I'm not really sure I buy the "heat the crawlspace" theory, because, in effect, with the ducts disconnected, the crawl space was being heated in Feb and there was still a temperature difference.

So, what would folks here recommend? What solutions have you all found that help?

Thanks and have a great day!

See my answer to your same question in the Holmes on Homes thread.

Is there adequate air return to the furnace?
Did anyone mention air volume dampers to those rooms?