Air sealing and insulating the crawlspace walls can often be a simpler approach than air sealing and insulating the floors, because the services running in the floor space do not have to be insulated. In a heated crawlspace, the crawlspace walls are insulated to make the space conditioned like the rest of the home. Ventilation from the exterior is not needed and existing vents should be sealed. Also, steps must be taken to stop moisture from the ground from entering the crawlspace. The main focus for air sealing is the rim joists and is similar to the interior approach to insulating a basement.

This air sealing and insulating procedure is for the interior approach only. Similar results can be achieved from the exterior.

Other insulation types such as spray foam can be used as alternatives to rigid foam board. However, batt insulation is not recommended as there is potential for condensation on the inside face of the concrete.