Navigating The 2024 Energy Code: What You Need to Know

The 2024 Illinois Energy Conservation Code took effect on November 30, 2025, bringing new requirements that directly influence the design and permitting of commercial and multifamily projects. For architects working on new construction, these requirements must be reflected in both the design and the permit documents.

The updated code places greater emphasis on building performance, including HVAC systems, lighting, controls, water heating, the building envelope, and overall energy use. Projects must also achieve a required number of additional efficiency points through qualifying measures. How those points are achieved can meaningfully shape the building design.

On a recent 36-unit multifamily project, for example, high-efficiency water heaters helped achieve the required efficiency points with minimal deviation from what the project already needed. Other compliance measures, however, can have much broader implications.

One of the biggest considerations for new commercial construction is solar. Depending on the building and applicable code requirements, roof-mounted photovoltaic systems or provisions to accommodate solar in the future may need to be incorporated. This can affect available roof area, electrical infrastructure, equipment placement, and the architectural design itself.

Requirements like these can create permit challenges if the selected efficiency measures or system provisions are not accurately reflected in the drawings and documentation submitted for review. A project that otherwise appears ready for permit may require revisions if its chosen compliance path does not satisfy the applicable code.

Before Submitting for Permit, Confirm:

• Which version of the energy code applies based on the project and permit date
• Which measures will be used to achieve the required efficiency points
• Whether photovoltaic or other renewable energy requirements apply
• How those requirements affect roof area, equipment placement, and electrical infrastructure
• How the building envelope and MEP systems contribute to compliance
• What calculations, drawings, and supporting documentation are required for permit review
• Whether the local jurisdiction has additional amendments or requirements

Energy code compliance now has a direct impact on decisions architects and project teams make throughout the design. Understanding the applicable requirements and clearly documenting the selected compliance path can help reduce revisions during permit review.

Neville Engineering supports architects, developers, and project teams in interpreting MEP and energy code requirements and developing practical, compliant solutions for new construction.

The requirements are already in effect. The key is ensuring they are fully reflected in the design before the project reaches permit review.