New Custom Energy Code Takes Effect in Illinois

Commercial buildings have long been the biggest energy users, accounting for 40% of total energy consumption (U.S. Department of Energy). With these buildings averaging 50-100 years, it’s more important than ever to invest in efficient and sustainable construction practices from concept through completion — efforts that can have a substantial impact on energy savings and the future of our environment.

In 2024, Illinois released its first integrated, custom energy code based on the 2021 International Energy Conservation Code (IECC), joining 13 other states that have adopted minimum energy codes based on the IECC or its equivalent.

The Illinois Energy Conservation Code establishes minimum requirements for commercial buildings, applying to the construction of, renovations to and additions to all commercial buildings in the State. It also establishes minimum and maximum requirements for residential buildings, applying to the construction of, renovations to and additions to all residential buildings in the State, except as provided for in Section R102.1.1.

According to EnergyCodes.gov, adopting the latest model codes in Illinois is estimated to reduce greenhouse gas emissions by 21,180,940 metric tons over 30 years. That’s the equivalent of 4.6 million passenger vehicles, or 2.6 million homes! In the residential market, the new code can save the average new homeowner nearly 10% on utility bills, according to a release from the International Code Council.

Illinois is also in the process of adopting a stretch energy code to allow municipalities and projects authorized or funded by the Capital Development Board to achieve more energy efficiency in buildings than the Illinois Energy Conservation Code through a consistent pathway across the State. The Illinois Stretch Energy Code is in development and is expected to be made available to the public later this fall.

On average 30% of the energy used in commercial buildings is wasted — U.S. Environmental Protection Agency