How Much Energy Is Saved With Crawlspace Insulation?

Crawling Space Heat Loss

• According to Kansas State University Engineering Extension, having an insulated foundation can reduce heating costs by up to 50 percent. The dirt that surrounds your crawl space is not a good insulator; it takes 11 feet of soil to provide the same amount of protection against heat loss as 2 inches of foam insulation. Without sufficient insulation, a crawl space can lose up to 47,000 BTUs per lineal foot per year.

Types of Insulation

• Two types of insulation will work in a crawl space. The first is fiberglass batting, which comes in rolls. Install batting in any unfinished wall, floor or ceiling by cutting the insulation to size and fitting it between joists or beams. The second option is rigid foam board. Foam board has the benefit of being thinner than batting. You install it in the same way as batting: cut it to size and place it between joists or beams.

R-Value

• Regardless of which type of insulation you use, you must also determine which R-value is appropriate for your crawl space. R-value is the level of thermal resistance that a certain material provides. The higher the R-value, the more effective insulation is at maintaining heat. The R-value you use depends largely on where you live. According to the Energy Efficiency and Renewable Energy Clearinghouse, if you are in the northern United States, use an R-value of 19. If you live in the middle of the country, R-10 is sufficient. Before you buy insulation, check their map of recommended R-Values.

Considerations

• Before insulating your crawl space, address moisture issues. Use gutters to keep rain from collecting around your foundation and slope the soil away from the house to avoid drainage issues.

  Ensure the crawlspace is airtight. Address air leaks by sealing off vents and other airflow passages.

  Consider sealing off your crawl space entirely to protect your family from radon and to save even more on your energy costs.