IL HB3510

Extends deadlines for adopting stricter Illinois Stretch Energy Code standards for residential buildings: site energy index of 0.40 deadline moves from December 31, 2025 to December 31, 2026; index of 0.33 moves from December 31, 2028 to December 31, 2029; index of 0.25 moves from December 31, 2031 to December 31, 2032

Extends identical one-year deadline extensions for commercial building stretch energy code standards: site energy index of 0.50 deadline moves to December 31, 2026; index of 0.44 moves to December 31, 2029; index of 0.39 moves to December 31, 2032

The Illinois Stretch Energy Code allows municipalities to voluntarily adopt more stringent energy efficiency requirements than the standard Illinois Energy Conservation Code, with separate components for residential and commercial buildings

Performance targets are measured using a site energy index relative to the 2006 International Energy Conservation Code, with lower index values indicating greater energy efficiency

The Capital Development Board may adopt slightly less restrictive standards if it identifies unanticipated burdens with previously adopted stretch codes, provided the relaxed standard still exceeds the applicable International Energy Conservation Code by at least 0.05