The US Department of Energy (DOE) has played a critical role in the development and dissemination of important energy-efficient technologies. Three of the most successful technologies-low-emissivity (low-E) windows, electronic ballasts and high-efficiency supermarket refrigeration systems-are reviewed in detail herein. DOE initiated R&D projects and worked in partnership with private companies to develop, refine, and demonstrate the technologies. Without DOEs financial and technical assistance, companies would not have been likely to pursue what were then perceived as high-risk, uncertain technologies. Combined, the technologies provided US manufacturers with ca $3.5 billion in additional sales revenues cumulatively throughout 1995, The primary energy savings from use of the technologies reached about 250 trillion Btus per year as of 1995, worth about $1.5 billion per year. Moreover, US consumers should realize net economic savings of around $10 billion over the lifetime of three technologies sold through 1995.