US Department of Energy commissioned the results of a national study on the consistency and replicability of the HERS Ratings System. SPEER, with the five other Regional Energy Efficiency Organizations, performed the research and compiled the results of the study of ratings in ten states across the U.S. The goal of this study was to evaluate the impact of increased participation of HERS Raters on the accuracy and consistency of the code enforcement process. The report notes widespread inconsistencies in raters’ documentation of critical energy measures. The national average variance of the ratings scores of individual houses was 13 points.