Internationally, code officials recognize the need for a modern, up-to-date energy conservation code addressing the design of energy-efficient building envelopes and installation of energy-efficient mechanical, lighting and power systems through requirements emphasizing performance. The International Energy Conservation Code is designed to meet these needs through model code regulations that will result in the optimal utilization of fossil fuel and nondepletable resources in all communities, large and small.

The 2015 IECC became effective in Illinois on January 1, 2016

The Capital Development Board (CDB), in conjunction with the Department of Commerce & Economic Opportunity (DCEO), has completed the cycle for the Illinois Energy Conservation Code (IECC) to update from the 2012 International Energy Conservation Code (IECC) to the 2015 IECC. In accordance with The Energy Efficient Building Act, CDB is required to review and adopt the most current version of the IECC within one year after its publication date. The Code will then become effective within 6 months following its adoption by CDB. The effective date for the 2015 IECC, with Illinois Amendments, to become law in the State of Illinois was January 1, 2016.

When developing Code adaptations, rules, and procedures for compliance with the Code, CDB is required to seek input from representatives of the building trades, design professionals, construction professionals, code administrators, and other interested entities affected by the new Code. To ensure input from these groups, CDB created the Illinois Energy Code Advisory Council (ILECAC) which has representatives from each of the groups listed above. Proposed amendments were accepted by the ILECAC from July 1, 2014 – December 1, 2014. The ILECAC reviewed all properly submitted, proposed amendments to the Code and, after deliberation, voted regarding the acceptance or rejection of these proposed amendments. The Council’s recommendations were then presented to the CDB. With CDB’s vote to accept the ILECAC’s recommendations, they were submitted to the Joint Committee on Administrative Rules (JCAR) for acceptance and implementation. JCAR Voted to accept CDB’s recommendations December 15, 2015.


Public Act 096-0778 was signed into law on August 28, 2009 amending the Energy Efficient Commercial Building Act by including residential buildings and amending the name of the act to the Energy Efficient Building Act.  The new requirements for residential buildings became effective on January 29, 2010.

Public Act 093-0936 (Energy Efficient Commercial Building Act) was signed into law in August, 2004. Thereby, an Illinois Energy Conservation Code for Commercial Buildings based on the 2000 International Energy Conservation Code (IECC), the American Society of Heating, Refrigeration and Air-conditioning Engineers (ASHRAE) 90.1-1999 Standard referenced therein, and the 2001 IECC Supplement to that Code, became effective April 8, 2006. On October 9, 2007 the Law was revised to mandate the latest published edition, excluding supplements, of the IECC. As of August 18, 2009 the Illinois Energy Conservation Code for Commercial Buildings was the 2009 IECC.  On August 28, 2009, Public Act 096-0778 requiring an energy code for residential buildings was signed into law.  It became effective January 29, 2010, establishing the 2009 IECC as the first energy code for residential buildings in Illinois.

Senate Bill 3724, signed by the Governor on August 17, 2012, amended the implementation date of the 2012 Illinois Energy Conservation Code to January 1, 2013.  The Bill also lengthened the time the ILECAC and CDB have to review and adopt future published editions of the Code and make them effective. This allowed stakeholders more time for training and preparation to build, design, and enforce the future updated codes.


The Law requires all new commercial and residential construction for which a building permit application is received by a municipality or county to follow a comprehensive statewide energy conservation code. Renovations, alterations, additions, and repairs to most existing commercial and residential buildings must follow the Illinois Energy Conservation Code. The Law requires design and construction professionals to follow the latest published edition of the International Energy Conservation Code (IECC) which is currently the 2015 IECC and the ASHRAE Standard 90.1-2013 “Energy Standard for Buildings except Low-Rise Residential Buildings,” referenced therein. Under the law, the Capital Development Board has the power to modify the Illinois Energy Conservation Code. The Illinois Office of Energy & Recycling in the Department of Commerce and Economic Opportunity is responsible for providing Training, Education and Technical Assistance in support.

Local governments are free to adopt stricter energy conservation Laws for COMMERCIAL BUILDINGS defined by the Law.  However, for RESIDENTIAL BUILDINGS defined by the Law, local governments may not adopt or regulate energy conservation standards either less or more stringent than the Illinois Energy Conservation Code.  Exceptions which would allow local governments to regulate energy efficient standards in a more stringent 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 stringent 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 stringent than the 2006 International Energy Conservation Code
  • A municipality with a population of 1,000,000 or more


The Law is designed to help protect the environment and reduce energy consumption. By following an energy conservation code, property owners can reduce air pollution, moderate energy demand and stabilize energy costs and electric, oil, and gas supplies.

The efficiency gains of the 2009 IECC set a new baseline for International Energy Conservation Code-compliant, new single- and multifamily homes, and while, there will be regional variability and uncertainty in technology penetration, quantitative estimates of National Energy & Cost Savings for New Single- and Multifamily Homes from U.S. DOE concluded that moving from a baseline of the 2006 IECC to the 2009 IECC reduces average annual energy costs by 10.8%, while moving from the same baseline 2012 IECC reduces them by 32.1%.  In its May 2015 report entitled 2015 IECC: Energy Savings Analysis, the U.S. DOE concludes that new single- and multifamily homes built to the 2015 IECC, compared with buildings built to the 2012 IECC, would result in an energy cost savings of approximately 0.82-0.63 percent for Illinois Climate Zones 4 and 5. In its June 2015 report entitled Energy and Energy Cost Savings Analysis of the 2015 IECC for Commercial Buildings, the U.S. DOE concludes that new commercial buildings built to the 2015 IECC, compared with buildings built to the 2012 IECC, would result in an energy cost savings of 11.5 percent on a national aggregated basis.

Air Conditioning Contractors of America (ACCA), provides free resources for code officials who need to increase their understanding of residential HVAC design tools like Manuals J, D and S. Their brochures are printable and offer a description of the various ACCA manuals and checklists for plans examiners to use. ACCA has an agreement in place with ICC so that Governmental Members can apply for free membership in ACCA. ACCA members get reduced rates on training and other resources sold by ACCA.

The Building Codes Assistance Project (BCAP) is a nonprofit advocacy organization that promotes the adoption, implementation and advancement of building energy codes on the state, local, and international levels. BCAP is a proud project of the Trust for Conservation Innovation (TCI).

The Building America Solution Center provides free access to expert information on hundreds of high-performance construction topics, including code briefs, publications, program checklists, and technical guides to building components.

  • Access the full Building America Solution Center here
  • Access the Code Briefs section here

Watch videos on duct sealing, air sealing, and ventilation from Washington State University, which applies to all climate zones.

Articles, guides, and popular building energy and moisture related topics

The solution center provides guidance, templates, videos and more. This initiative is designed to make residential and commercial properties more energy efficient in a number of ways, including sharing of successful best practices and describing lessons learned from program administrators, implementers and contractors who have operated across the country.

Are you interested in purchasing a quality home or townhouse in Illinois?  Do you want to learn more about how to make your existing home more energy-efficient?

  • DOE’s Building Energy Codes Program Compliance Software Tools
    • REScheck: Used to show compliance on residential building plans
    • COMcheck:  Used to show compliance on commercial building plans
    • Other forms of compliance may be used as approved by the Authority Having Jurisdiction.
    • USDOE’s Solutions & Help Center – Help with compliance software


Residential Buildings

Commercial Buldings

ANSI/ASHRAE/IES Standard 90.1:

International Energy Conservation Code (IECC):


Resource Guides

BECP has also developed a series of resource guides — each focused on a particular practice or stakeholder group, and providing guidance on common challenges, best practices, and related resources.

Are you interested in purchasing a quality home or townhouse in Illinois? Do you want to learn more about how to make your existing home more energy-efficient?

  • Illinois Consumer Checklist This checklist is designed to help you spot check for compliance with the Illinois Energy Conservation Code. While it does not include every requirement, this checklist will help you assess a home and make an informed decision about the quality of construction and efficiency of a home.
  • Illinois Consumer Guide – This guide provides a quick way to assess home energy performance. The guide describes the minimum standards of construction practice for new homes in Illinois based on the 2012 International Energy Conservation Code (IECC) with amendments as the Illinois Energy Conservation Code. While it does not include every requirement, this will help you assess your own home, and if you are in the market for a new home, make an informed decision about the quality of construction and efficiency for the new home purchase.


  • To promote professionalism through education, training and certification of qualified officials;
  • To unify the various code administration organizations within the State of Illinois and to provide for the development of new organizations for statewide coverage;
  • To promote the development and adoption of a unified statewide code;
  • To promote the proper administration and enforcement of building and related codes.



  • To achieve recognition as professionals that contribute to the overall welfare of the public by providing the most current knowledge to a safe enviroment;
  • To communicate to the public and elected officials the role of the Code Official in developing codes that safeguard public health, safety and welfare;
  • To be recognized as an organization that will unite together to benefit all Code Enforcement personnel through the entire State of Illinois.


A complete list of Illinois ICCA Chapters can be found here.

Illinois Baseline Compliance Study – Measuring the Baseline Compliance with Residential and Non-Residential Buildings in Illinois against the 2009 and 2012 International Energy Conservation Code.

Success with the Illinois Energy Code….

Find a diagnostic energy tester.

  • Illinois Resources For Builders & Code Officials — Success with the Illinois Energy Code
    Tech Tips, Trade Checklists & Code Officials Checklist – Downloadable and printable

The Illinois Department of Commerce Office of Energy & Recycling’s  schedule for another training series directed at the Illinois construction industry is now available. Homebuilders, general contractors, architects, engineers, code officials, HVAC specialists, realtors, new and existing Chicago REP’s and home performance professionals will be able to learn about the newest energy conservation codes for new construction, additions and renovation projects in Illinois. Sessions will be offered to Illinois Investor-Owned energy companies customers at no cost.  View course offerings HERE.

Additional classes will be listed soon.

The International Code Council is a member-focused association. It is dedicated to developing model codes and standards used in the design, build and compliance process to construct safe, sustainable, affordable and resilient structures. Most U.S. communities and many global markets choose the International Codes. International Code Council Members include state, county and municipal code enforcement and fire officials, architects, engineers, builders, contractors, elected officials, manufacturers and others in the construction industry. The International Code Council has more than 350 Chapters. Each Chapter has its own personality and focus, representing all International Code Council member professional disciplines.

At the Midwest Energy Efficiency Alliance, we leverage our unique position as the Midwest’s key champion and trusted information resource on energy efficiency policies and programs to help our members and stakeholders identify, understand and implement cost-effective strategies that provide economic and environmental benefits.
As a collaborative network and an influential membership organization spanning thirteen states, we provide a professional forum where energy providers, policymakers, implementers, manufacturers and advocates can make connections, seek advice and learn about energy efficiency. With our dynamic annual conference, MEEA plays an important role in forging partnerships, promoting new technologies and curating the evolving conversation around economic sustainability and environmental stewardship from energy efficiency.

Insulation Video Series provided by North American Insulation Manufacturers’ Association (NAIMA). The NAIMA Series covers:

  • Pre-insulation inspection, air-sealing evaluation.
  • What a good insulation installation looks like.
  • What to look for in an insulation inspection.

These videos demonstrate best practices in installing batt insulation in homes.