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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 2024 edition of the IECC as amended went into effect on 11/30/25.
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 2024 edition of the IECC as amended went into effect on 11/30/25.
| 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) will become effective 11/30/25.
- Illinois Specific Amendments
- 2024 IECC Cost Effective Analysis