Illinois: New Year, New Energy Code


You may not have noticed, but on January 1, 2016, the 2015 Illinois Energy Conservation Code became law, based on the approval from the Joint Committee on Administrative Rules at the December hearing. This updated code is an amended version of the 2015 International Energy Conservation Code (IECC) (the latest national model code) and provides minimum energy standards for all new residential and commercial buildings. The Illinois Capital Development Board, in conjunction with the Department of Commerce and Economic Opportunity, updates the code every three years, as Illinois is one of the states in the Midwest with a legislative requirement to update their energy code to the latest national model code, within a year of its release. The previous version of the Illinois Energy Conservation Code was based on the 2012 IECC and was adopted on January 11, 2013.

Now, I know what you’re thinking: “That’s great that the State of Illinois has an updated Building Energy Code, but what does it mean for building efficiency and what changes were made?”

Efficiency Improvements

When comparing 2015 to the 2012 Illinois Energy Conservation Code, there were minimal efficiency improvements to the Residential Section (Chapter 11 in IECC) and moderate efficiency improvements to the Commercial Section (Chapter 5 in IECC/ASHRAE Standard 90.1-2013) when compared to the improvements in efficiency in the 2013 update. Although we do not know the exact efficiency improvement to the residential section of the Illinois Code (because Illinois is implementing an amended version of the 2015 IECC), according to the Department of Energy (DOE) final determinations, the Residential Section of the unamended 2015 IECC is approximately 1% more efficient (site energy savings) than the 2012 IECC.

The Commercial section in the Illinois Code is roughly equivalent to the national model code, so, according to the DOE final determinations, the Commercial Section is approximately 7.6% more efficient than the previous national model code.

The improvement in efficiency for all new buildings will result in reduced energy use and lower costs for the tenant or homeowner.

Changes from 2012 IECC

Residential Section

The residential section of the 2015 Illinois Energy Conservation Code experienced relatively few changes when compared to the 2012 version, but as with any update, there are minor improvements which make it easier to read and use. The two major changes made to the residential section of the code are:

  1. New Compliance Option – The Energy Rating Index (ERI) has been added to the code as an alternative performance compliance option for builders to meet the code requirements. The ERI is based on a scale of 0 to 100, where 0 is a zero energy home and 100 is a home based on the 2006 IECC. In order to comply with the code, a home must, at a minimum, achieve an ERI score of 55, the mandatory code requirements, and the 2009 IECC insulation and fenestration requirements.
  2. Basement Insulation Option – In the basement, residential builders now have the option to install either (1) R-10 continuous or R-13 cavity (10/13) ten feet below grade, or six inches above the floor, or (2) install R-15 continuous or R-19 cavity (15/19)  a minimum of four feet below grade.

Commercial Section – ASHRAE Standard 90.1-2013

As indicated by the improvement in efficiency, there are significant changes to the Commercial Section of the 2015 Illinois Energy Conservation Code when compared to the 2012 version. Although there is not enough time (or space) to discuss all the 110 changes in detail, DOE identified eight major changes which positively impact energy use. In general, these improvements require a more efficient building envelope, increased efficiency requirements on mechanical equipment, and improved lighting, daylighting and controls. A description of all changes can be found in the DOE Standard 90.1-2013 Determination of Energy Savings: Qualitative Analysis.

The eight major changes that contribute to the improved efficiency of a building are below:

  1. Addendum 90.1-2010bb – This change requires increased insulation values for opaque wall assemblies in most climate zones. More efficient windows are also required.
  2. Addendum 90.1-2010m – This change adds lighting control requirements for interior and exterior lighting alterations.
  3. Addendum 90.1-2010u – This change now requires a minimum efficiency requirement for all fans. Each fan must now have a “Fan Efficiency Grade (FEG)” of 67 or higher.
  4. Addendum 90.1-2010aq – This change expands the requirements for fan speed control to other applications and requires improved economizer efficiency.
  5. Addendum 90.1-2010am – This change requires boilers comply with a specified turndown ratio to reduce energy use.
  6. Addendum 90.1-2010bq – This change adds new efficiency requirements for commercial refrigeration. These requirements apply to walk-in coolers and freezers, refrigerated display cases, condensers and compressor systems.
  7. Addendum 90.1-2010by – This change requires lighting controls be placed in additional spaces and reduces the light sensor timer.
  8. Addendum 90.1-2010co – This change requires a decrease of lighting power density (LPD) in most building types.

For additional information about the 2015 Illinois Energy Conservation Code, please contact Ian Blanding, Building Policy Associate at MEEA.

For training opportunities, technical resources or code interpretation requests, please review the Illinois Department of Commerce and Economic Opportunity Energy Conservation Code website.