Proper crawlspace insulation can improve your home's comfort and energy efficiency. An unheated crawl space can send cold air up through the floor of your home, making your heating system work harder. Crawlspace insulation manufacturer Owens Corning advises adding fiber glass insulation batts between the joists in the crawl space ceiling.
Here's how: Always install the crawl space insulation with the vapor retarder toward the warm side of the structure in heating climates. In a vented crawl space, the warm side is usually up, closest to the floor. Water pipes should also be insulated and you will need to insulate carefully around electrical wiring and boxes.
Crawlspace insulation should be placed around cross braces by cutting it and pushing it between the braces. Once the crawlspace insulation is in place between the floor joists, insulation hangers or nylon straps can be used to hold the product in place. A 4- or 6-mil polyethylene vapor retarder should be laid down to completely cover the ground. Place rocks or bricks around the perimeter to hold it in place.
In cold weather, crawlspace insulation is your friend. An under insulated home means a lot more energy used to heat or cool it - and a lot more money spent when the bills come in.