This report focuses on single-family and low-rise multifamily residential buildings based on the International Energy Conservation Code (IECC). The IECC is developed by the International Code Council (ICC) on a 3-year cycle through a public development and public hearing process. While proponents of code changes often include the energy and cost-effectiveness criteria for their respective code change, the IECC process does not include an energy or cost-effectiveness analysis of the entire edition of the code.
PNNL evaluated the cost effectiveness of the changes in the prescriptive and mandatory residential provisions of the 2021 edition of the IECC, hereafter referred as the 2021 IECC, compared to those in the prior edition, the 2018 IECC.