Pacific Northwest National Laboratory (PNNL) conducted a series of cost effectiveness analyses for the U.S. Department of Energy (DOE), covering the 2009 and 2012 editions of the International Energy Conservation Code (IECC) for new single and multifamily homes. The evaluations were performed against a 2006 IECC baseline, taking state-specific code amendments into consideration. These reports outline the results of these analyses, including a National Cost Analysis and Cost Analyses for selected states.