The manufacturing sector of the U.S. economy, consisting of 21 three-digit NAICS industries that produce the nation’s durable and non-durable goods, purchases a significant fraction of all the energy sold in the country each year. Important though this sector is, the economic determinants of energy use as an intermediate input in the production process, and the impacts of energy efficiency policies, are somewhat clouded in mystery. In this new study, NAICS-level energy-related data are analyzed and compared from three different federal government data sources, i.e., the Manufacturing Energy Consumption Survey (MECS) produced by EIA, the Annual Survey of Manufacturers (ASM) produced by Census, and the Intermediate Industry Accounts (IIA) produced by BEA. Differences in the data, and different analytic methods, are found to produce different estimates of energy efficiency progress. However, when using a common econometric model specification there appears to be some consistency in the findings related to public policy impacts.