(20 ILCS 3125/45)
    Sec. 45. Home rule.
    (a) No unit of local government, including any home rule unit, may regulate energy efficient building standards for commercial buildings in a manner that is less stringent than the provisions contained in this Act.
    (b) No unit of local government, including any home rule unit, may regulate energy efficient building standards for residential buildings in a manner that is either less or more stringent than the standards established pursuant to this Act; provided, however, that the following entities may regulate energy efficient building standards for residential buildings in a manner that is more stringent than the provisions contained in this Act: (i) a unit of local government, including a home rule unit, that has, on or before May 15, 2009, adopted or incorporated by reference energy efficient building standards for residential buildings that are equivalent to or more stringent than the 2006 International Energy Conservation Code, (ii) a unit of local government, including a home rule unit, that has, on or before May 15, 2009, provided to the Capital Development Board, as required by Section 10.18 of the Capital Development Board Act, an identification of an energy efficient building code or amendment that is equivalent to or more stringent than the 2006 International Energy Conservation Code, and (iii) a municipality with a population of 1,000,000 or more.
    (c) No unit of local government, including any home rule unit or unit of local government that is subject to State regulation under the Code as provided in Section 15 of this Act, may hereafter enact any annexation ordinance or resolution, or require or enter into any annexation agreement, that imposes energy efficient building standards for residential buildings that are either less or more stringent than the energy efficiency standards in effect, at the time of construction, throughout the unit of local government.
    (d) This Section is a denial and limitation of home rule powers and functions under subsection (i) of Section 6 of Article VII of the Illinois Constitution on the concurrent exercise by home rule units of powers and functions exercised by the State. Nothing in this Section, however, prevents a unit of local government from adopting an energy efficiency code or standards for commercial buildings that are more stringent than the Code under this Act.
(Source: P.A. 99-639, eff. 7-28-16.)