As part of the U.S. Department of Energy Building Energy Codes Program's support for the development and implementation of model building energy codes and standards for new residential buildings, DOE analyzes each new edition of the International Energy Conservation Code to assess its cost effectiveness relative to the prior edition. This report estimates the incremental cost to comply with the 2018 IECC relative to the 2015 IECC, the associated energy savings, and the life-cycle cost savings.