Knowledge Center: Department of Energy Insulation Recommendations
The Department of Energy supplies detailed, scientifically calculated recommendations for each state based on climatic and economic factors. For the convenience of our customers, we provide some of this information below.
These suggested R-values and guidelines should not be considered absolute minimums and may differ from your local building codes which should be followed. Insulate walls of a crawl space only if it is always dry, the floor above is not insulated, and there is no open ventilation to the crawl space. A vapor barrier should be installed on the ground to keep moisture out of the crawl space. Do not use slab edge insulation.
For more information, including DoE information for states not listed above, see simplyinsulate.com