Primary Contact for State Adoption

Lisa Hennigh
Administrator of Professional Services

Capital Development Board

3rd Floor Wm. G. Stratton Building
Springfield, IL 62706
United States

Secondary Contact for State Adoption

Chad Kruse
Manager, Illinois Office of Energy

Illinois Environmental Protection Agency

100 W. Randolph St. #11-300
Chicago, IL 60601
United States

Regional Energy Efficiency Organization

Chris Burgess
Buildings Director

Midwest Energy Efficiency Alliance (MEEA)

United States

State Profile

Code Type: Commercial Residential
Current State Code 2018 IECC with Amendments 2018 IECC with Amendments
Effective Date
Adoption Date
Enforcement Mandatory Statewide Mandatory Statewide
State Amendment Yes Yes
Can use COM/REScheck Yes Applicable by County or Jurisdiction


Commercial Residential
Current Model Code ASHRAE Standard 90.1-2010 2012 IECC
Yes Yes

State Code Analysis

Code Type: Residential Commercial
Energy Efficiency
State Amendment Yes Yes
Amendment Summary

Model Code Savings Potential

Statewide Savings Potential (2010-2030) Residential Commercial
Cost $0.49B $0.75B
Energy (primary) 44MBtu 88MBtu
Consumer Cost Savings Residential
per Home
per 1,000 ft2
Annual ($) $5 $110
Annual (%) 0.3%
Life-cycle (30 year) $76 $920
Simple Payback 2.3 years 13.2 years
Positive Cash Flow 0.3 years


Code Type: Residential Commercial
Field Study Yes Yes
Training Program No No


Additional Information

    The primary energy conservation law in Illinois was the Illinois Public Utilities Act (revised in 1986). This law required Illinois investor-owned electric utilities to use least-cost energy planning, which required the use of economical energy conservation when new resources for electricity were required.

    The Energy Conservation Code for state projects was approved by legislators in 2003 and the administrative rules for the law were developed by CDB and approved by the General Assembly's Joint Committee on Administrative Rules in 2004 and updated to include the 2004 edition of ASHRAE Standard 90.1.

    The administrative rules moving the energy code for commercial buildings to the 2006 edition of the International Energy Conservation Code were adopted by CDB and the Joint Committee on Administrative Rules and became effective October 9, 2007.

    On Friday, August 28, 2009, Governor Pat Quinn signed the Energy Efficient Building Act into law. The Act established a statewide residential energy code, which requires that newly constructed residential buildings meet the minimum standards set forth in the most recent version of the International Energy Conservation Code (2009 IECC). The Illinois Capital Development Board (CDB) must now review and adopt the code though an administrative proceeding.

    The requirements of the new energy code will apply to all new residential and commercial buildings (including alterations, additions, renovations, and repairs). Local jurisdictions would be prohibited from adopting energy codes more or less energy efficient for residential buildings (although exemptions are provided for municipalities that have already adopted a code equivalent to or more energy efficient than the 2006 IECC [before May 15, 2009] or those that have a population of more than 1 million) and from adopting energy codes less energy efficient for commercial buildings.

    Senate Bill 3724, signed by the Governor on August 17, 2012, amends the effective date of the 2012 IECC to January 1, 2013.  Administrative Rules to adopt the 2012 IECC with amendments were approved by the Joint Committee on Administrative Rules on December 11, 2012.

    On August 24, 2009 Illinois Governor Quinn signed SB 1601, enacting Public Act 96-0630. The act, to take effect in January 2010, addresses several components of building design to improve sustainability through renovation projects. LEED and Green Globes certification costs are funded by the Illinois Tax Increment Fund.

    On July 24, 2009, Governor Quinn signed into law HB 1013, requiring all new state-funded building construction and major renovation of existing state-owned facilities to seek LEED or equivalent certification. New buildings and major renovations of 10,000 sq ft or more must achieve at minimum LEED Silver or equivalent certification. New buildings and major renovations under 10,000 sq ft must strive to meet the highest standard of the LEED rating system or equivalent, but are not required to achieve certification.

    The Illinois State Senate amended the School Construction Law (Public Act 95-0416) with governor approval, directing the Capital Development Board to only issue grants to school projects with LEED for Schools or comparable rating system certification, or to projects that meet the standards set forth by the Capital Development Board Green Building Advisory Committee.

    State Funded Facilities must comply with ASHRAE 90.1 per 20 ILCS 3105/10.09-5. See Subpart B of the Illinois Energy Conservation Code for more information.The 2013 edition of ASHRAE 90.1 went into effect on 1/1/16.

    Privately Funded Commercial Facilities must comply with IECC per 20 ILCS 3125.See Subpart C of the Illinois Energy Conservation Code for more information. The 2015 edition of the IECC went into effect on 1/1/16.

    The state and local governments can adopt building codes. Local governments are free to adopt stricter energy conservation Laws for commercial buildings. However, for residential buildings, local governments may not adopt or regulate energy conservation standards either less or more energy efficient than the Illinois Energy Conservation Code.

    Exceptions which would allow local governments to regulate energy efficiency standards in a stricter manner are municipalities or counties which meet one of the following three provisions:

    • A unit of local government that on or before May 15, 2009 adopted or incorporated by reference energy efficient building standards for residential building that are equivalent to or more energy efficient than the 2006 International Energy Conservation Code.
    • A unit of local government that on or before May 15, 2009 provided to the Capital Development Board identification of an energy efficient building code or amendment that is equivalent to or more energy efficient than the 2006 International Energy Conservation Code.
    • A municipality with a population of 1,000,000 or more.