Expanding energy conservation and efficiency in every sector nationwide is one of the most cost-effective instruments for reducing US energy imports, the trade deficit and energy's environmental impacts. For these reasons, energy conservation and efficiency have been essential elements of US energy policy since the oil embargos and price spikes of the 1970s. The Energy Independence and Security Act of 2007 (EISA) is the latest federal legislation to expand and strengthen US energy conservation and efficiency policies, programs, and practices. Specifically. EISA and its recent predecessor, the Energy Policy Act of 2005 (EPAct05), contain almost 200 titles with new provisions for energy conservation and efficiency aimed at improvements in vehicle fuel economy. These provisions include efficiency of appliances and lighting; energy savings in residential, commercial, and government buildings; the efficiency of industrial manufacturing plants; and the efficiency of electric power delivery and end-use. These actions have begun to contribute to new federal, state, and local policies, programs, and practices across the US, and expectations are high for increases in the level of energy savings. This paper summarizes the history of US energy conservation and efficiency policies, outlines EISA's and EPAct05's key provisions, and considers prospects for the future. (C) 2010 Elsevier Ltd. All rights reserved.