Energy Star is a voluntary energy efficiency-labeling program operated jointly by the United States Department of Energy (U.S. DOE) and the United States Environmental Protection Agency (U.S. EPA). U.S. DOE and U.S. EPA enter into partnerships with manufacturers and key stakeholders to promote products that meet energy efficiency and performance criteria established by the agencies. The Energy Star label allows consumers to more easily identify and purchase energy-efficient products. By transforming the market for high-efficiency products, U.S. DOE and U.S. EPA reduce air pollution and greenhouse gases associated with energy consumption. Since the program inception in 1992, Energy Star has become a leading international brand for energy efficient products. Energy Star's central role in the development of regional, national, and international energy programs necessitates an open process whereby its program achievements to date, as well as projected future savings, are shared with stakeholders and the public. Energy Star consists of three programmatic areas: products, buildings and industrial plants, and homes. This report focuses only on labeled products that are administered by the U.S. EPA, such as office equipment, appliances, and electronics. It does not cover savings for buildings and industrial plants, homes, or labeled products administered by U.S. DOE. The methodologies for quantifying savings for these other Energy Star program segments are significantly different than the methodology (for U.S. EPA-labeled products) outlined in this report, and cannot be addressed here in adequate detail. Numerous supporting stakeholders, including utilities, regional energy partnerships, energy consortia, and nonprofit organizations, leverage the Energy Star program nationally. All stakeholders work toward advancing Energy Star goals, improving Energy Star consumer awareness, and promoting the sales of Energy Star products. This report provides a top-level summary of national savings achieved by Energy Star voluntary product labeling and does not make an attempt to attribute the national savings across federal, regional, state, and/or local efforts. Today, U.S. EPA Energy Star includes over forty individually labeled products and has implemented over 70 specification revisions. To best quantify and analyze savings for all products, we developed a bottom-up product-based model. Each Energy Star product type is characterized by product-specific inputs that result in a product savings estimate. Energy Star program impacts are the sum of the impacts for each individual Energy Star product type. The bottom-up model allows us to separately evaluate the implementation process for each product type and quantify Energy Star's impact within each market. The model results inform U.S. EPA's product development strategy by providing valuable feedback regarding existing Energy Star market share and untapped market potential, a ranking of savings by product type, and impacts of ongoing specification revisions. Since Energy Star specifications are often a key component of many regional energy efficiency efforts, the bottom-up model allows U.S. EPA to provide critical product data to facilitate the development of localized programs.