Six Most Important IECC Building Codes Changes


As many developers, architects and home builders know, tenant and consumer demand for energy cost savings continues to grow. According to the U.S. Department of Energy, Wisconsin will adopt the 2015 International Energy Conservation Code (IECC) beginning in 2017.

Currently, Illinois is the only other Midwest state to have adopted the 2015 IECC code, as many of the states still have the 2012 or 2009 versions.

Changes in 2015 IECC code

Following are six major changes found in the 2015 IECC code for new home construction that builders should notice:

  1. Energy Rating Index (ERI) compliance path: Builders now have the option of meeting a target ERI score through a wide range of performance options to demonstrate compliance.
  2. Specify required inspections: Builders now need to specify when the inspection should be done and what should be inspected.
  3. Vertical access doors: Vertical doors do not have to be insulated to the same level as the surrounding wall, as long as they meet the fenestration U-factor requirements.
  4. Combustion closets: With rooms that contain fuel burning appliances, the appliance and combustion air opening should be located outside the building thermal envelope or enclosed in a room, isolated from inside the thermal envelope.
  5. Building envelope air leakage testing changes: Requires that one of the two ASTM standards (ASTM E 779 or ASTM E 1827) be followed when doing an air leakage test.
  6. Duct insulation: Requirements depend on location and the diameter of the duct.


For more information on Wisconsin building code requirements, please contact Laurie Dischler at