20 ILCS 3125/5

(a) The legislature finds that an effective energy efficient building code is essential to: (1) reduce the air pollutant emissions from energy consumption that are affecting the health of residents of this State; (2) moderate future peak electric power demand; (3) assure the reliability of the electrical grid and an adequate supply of heating oil and natural gas; and (4) control energy costs for residents and businesses in this State. (b) The legislature further finds that this State has a number of different climate types, all of which require energy for both cooling and heating, and that there are many cost-effective measures that can reduce peak energy use and reduce cooling, heating, lighting, and other energy costs in buildings.