I'm going to deviate a little from my normal pattern here.

I just ran across a story (printed, sorry no link) about encapsulated crawlspaces. It was touting the energy savings that could be realized by encapsulating the crawlspace. I have seen some claims as high as 15% savings in heating a cooling.

More importantly, I think there are some other benefits that could be realized, especially with older homes. one of the things I see all of the time is missing or incomplete vapor barriers. What happens then is that increased (uncontrolled) moisture can be introduced in to the house through the crawlspace. Even when the moisture barrier is complete and well sealed, the tradition is for the crawlspace to be openly vented to outside air. So... if it rains, that will also introduce uncontrolled moisture into the crawlspace. Of course, all of this moisture is going to end up in the house.

The moisture isn't necessarily bad, but the problem is that areas like crawlspaces don't have good airflow. Moisture + stagnant air = mold. Mold is bad.

So, if we can install a system that tightly controls humidity, lowers counter temperature air infusion, and therefore creates cleaner air that is more efficient to heat or cool, it sounds like a win/win.

The downside is that most of the systems I have heard of cost from $6,000 to $12,000 to install. For many homes, that is money that will neither be recaptured through resale or through energy savings. But, it may be something that decreases contaminants in the inside air.

Food for thought.