Chicago buildings The Energy Efficient Building Act is designed to help protect the environment and reduce energy consumption. By following an energy conservation code, property owners can reduce air pollution, moderate energy demand and stabilize energy costs and electric, oil, and gas supplies.

The efficiency gains of the 2009 IECC set a new baseline for International Energy Conservation Code-compliant, new single-and multifamily homes, and while, there will be regional variability and uncertainty in technology penetration, quantitative estimates of  National Energy & Cost Savings for New Single-and Multifamily Homes from U.S.DOE concluded that moving from a baseline of the 2006 IECC to the 2009 IECC reduces average annual energy costs by 10.8%, while moving from the same baseline 2012 IECC reduces them by 32.1%. In its May 2015 report entitled  2015 IECC: Energy Savings Analysis, the U.S.DOE concludes that new single-and multifamily homes built to the 2015 IECC, compared with buildings built to the 2012 IECC, would result in an energy cost savings of approximately 0.82-0.63 percent for Illinois Climate Zones 4 and 5. In its June 2015 report entitled  Energy and Energy Cost Savings Analysis of the 2015 IECC for Commercial Buildings, the U.S.DOE concludes that new commercial buildings built to the 2015 IECC, compared with buildings built to the 2012 IECC, would result in an energy cost savings of 11.5 percent on a national aggregated basis.