Illinois

Current Energy Code Status

	Residential	Commercial
Current State Code	2024 IECC	2024 IECC and ASHRAE 90.1-2022
State Amendments	Yes	Yes
Equivalent Code*	2024 IECC	90.1-2022
Amendments Efficiency Impact (Compared to Model Adopted Code)	0.00%	11.50%
Effective Date	11/30/2025	11/30/2025
Enforcement	Mandatory Statewide	Mandatory Statewide
Can use COMcheck / Rescheck	Yes	Yes

*Equivalent Code is based on a quantitative analysis of the state code with amendments as displayed in the Residential and Commercial Status of State Energy Code Maps.

State Certifications

Federal law directs states to review and update their building energy codes regarding energy efficiency and submit related certifications. The following is the most recent certification submitted by the state.

States are required by statute to submit certifications within 2 years of the publication of an affirmative determination of a new model energy code. Learn more about the statutory requirements.

Most Recent Submitted Certification

• Residential: 2012 IECC
• Commercial: ASHRAE Standard 90.1-2010

Model Energy Code Impacts

Key metrics related to incremental construction costs and consumer energy cost savings.

Energy and Economic Impacts

Model Energy Code	Measure	Energy Cost Savings
Residential Statewide Impact  Potential (2024 IECC)	Incremental First Cost of 2024 IECC ($/home)	$ -
	Annual Energy Cost Savings ($/home)	$ -
	Annual Energy Savings (kBtu/home)	-
	30 year Life Cycle Cost (LCC) Savings ($/home)	$ -
	Simple Payback Period (years)	NA
	Housing Starts (15 year average)**	9,859
	Statewide Total Incremental Cost Impact ($)	$ -
	Statewide First Year Energy Cost Savings  ($)	$ -

Illinois has adopted energy codes that perform equally or better than the 2024 IECC.
** Based on 2020 U.S Census, American Housing Survey 15 year average housing starts

Contacts