Illinois enforces one of the newest energy codes in the country statewide, and Chicago writes its own on top of it. We work to whichever applies to the project.

The same services in every state

Adicot provides the same engineering services in every state it is licensed in, for industrial, commercial and multi-family buildings of any size. What changes from state to state is the code the work is held to.

Cooling Load/Heat Load Calculations: room-by-room loads worked with ASHRAE methods, with ventilation rates to the adopted code
Energy Code Compliance: the building modeled and compliance demonstrated on performance, in the format the plan reviewer expects

Both are sealed by a professional engineer licensed in the state. Get a Quote to see the fee.

The codes in force in Illinois

As of October 2026:

Energy: the Illinois Energy Conservation Code, which is the 2024 International Energy Conservation Code with Illinois amendments, in effect since November 30, 2025. It applies statewide to privately funded commercial buildings, whether or not the municipality has a building code of its own.
Stretch code: the Illinois Stretch Energy Code is available for municipalities to adopt in place of the base code.
Mechanical: Illinois has no statewide mechanical code. The mechanical code is the one the municipality has adopted.

What is particular to Illinois

Chicago. Chicago has its own energy code, the Chicago Energy Transformation Code, and its own mechanical code. In June 2026 the City Council adopted updated construction codes based on the 2024 model codes, so a Chicago project needs its permit date checked against the changeover.

Mechanical code by municipality. With no statewide mechanical code, ventilation rates and mechanical requirements come from the edition each municipality has adopted. We confirm it with the local building department.

Climate. Illinois is in climate zone 5A in the north and 4A in the south.