Slabs can be big culprits for energy loss from heat that is conducted outward and through the perimeter of the slab. Slab insulation can save businesses and single-family residences up to 8% on heating use while preventing issues with condensation and discomfort.
The current Illinois Energy Conservation Code (2018 IECC) has requirements for slab-on-grade insulation. There are several code-accepted methods for placement of insulation, either inside or outside the foundation, to meet the needs of each unique condition. This Energy Smart Tip summarizes the code requirements as they apply to Illinois and provides guidance on construction details for durability and code compliance.