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Illinois residential energy code
Illinois residential energy code (2024 IECC as amended by Illinois)
As of 2026-10-22. DOE's Building Energy Codes Program (energycodes.gov) lags state adoption, so where a state's own rule was read it governs and DOE's differing figure is noted. Residential means one- and two-family dwellings and townhouses. Local amendments can apply; check the code body before relying on a section.
Key features
- Code in force: 2024 IECC as amended by Illinois
- In force since: 2025-11-30
- Adoption: Statewide mandatory code
- Status of the Illinois stretch code was not confirmed.
- Verified against the state's own adopted rule or code-body page.
Governing body
State of Illinois
Region
IL
Category
code