This study represents the most elaborate assessment to date of U.S. residential sector electricity efficiency improvements. Previous analyses (Bodlund et al. 1989, Geller et al. 1986, Hunn et al. 1986, Krause et al. 1987, Lovins 1987, Meier et al. 1983, Miller et al. 1989, NEEPC 1987, NPPC 1986, NPPC 1989, Usibelli et al. 1983, XENERGY 1990) have estimated the conservation potential for other countries, states, or individual utility service territories. As concern over greenhouse gas emissions has increased, interest has grown in estimates of conservation potential for the U.S. residential sector as a whole. The earliest detailed estimate of U.S. conservation potential is now out of date (SERI 1981), while more recent estimates (Carlsmith et al. 1990, EPRI 1990) are less detailed than is desirable for engineering-economic estimates of the costs of reducing carbon emissions. In this paper, we first describe the methodology for creating supply curves of conserved energy, and then illustrate the subtleties of assessing the technical conservation potential. Next, we present the data and forecasts used in this assessment, including costs, baseline thermal characteristics, energy use, and energy savings. Finally, we present the main results and conclusions from the analysis, and discuss future work.