Illinois Energy Conservation Code

(20 ILCS 3125/15)

Privately Funded Commercial Facilities must comply with the Illinois Energy Conservation Code per 20 ILCS 3125. See Subpart C of the Illinois Energy Code for more information. The 2021 edition of the IECC as amended went into effect on 1/1/24.

Residential Buildings must comply with Illinois Energy Conservation Code per 20 ILCS 3125. See Subpart D of the Illinois Energy Code for more information. The 2021 edition of the IECC as amended went into effect on 1/1/24.

The Illinois Energy Conservation Code (Base Code) is available online at https://codes.iccsafe.org/ Amendments to the Model Code are shown below.

2024
- The 2024 Illinois Energy Conservation Code (Base Code) is now under development. Additional information can be found on the 2024 Base Code Proposals page.