This Technical Support Document (TSD) describes the process, methodology and assumptions for development of the 50% Energy Savings Design Technology Packages for Highway Lodging Buildings.This design guidance document provides specific recommendations for achieving 50% energy savings in highway lodging properties over the energy-efficiency levels contained in ANSI/ASHRAE/IESNA Standard 90.1-2004 (ANSI/ASHRAE/IESNA 2004a). These 50% savings design packages represent a further significant step towards realization of the U.S. Department of Energy's (DOE) net-zero energy building goal for new construction by the year 2025. DOE has previously supported the development of a series of 30% energy savings design guides, which were developed by a partnership of organizations, including the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (ASHRAE), the American Institute of Architects (AIA), the Illuminating Engineering Society of North America (IESNA), the United States Green Buildings Council (USGBC), as well as DOE 1 .This report provides recommendations and user-friendly design assistance to designers, developers, and owners of highway lodging properties and is intended to encourage steady progress towards net-zero energy performance in these buildings. The design package provides prescriptive recommendation packages that are capable of reaching the 50% energy savings target for each climate zone, thereby easing the burden of the design and construction of highway lodging with exemplary energy performance.To develop the set of energy efficiency measure recommendations that meet, or exceed, the 50% goal, we used a highway lodging prototype, adapted from previous work for achieving 30% savings in the Advanced Energy Design Guide for Highway Lodging Buildings (AEDG-HL), to represent this class of buildings.We created baseline models from the prototype that are minimally code-compliant with ASHRAE 90.1-2004, and advanced models based on the recommended energy-efficient technologies. To determine the energy savings at different climate locations, we performed EnergyPlus simulation analyses. The simulation approach used is documented in this TSD, along with the characteristics of the prototype and assumptions of the baseline and advanced models.Finally, we assessed the cost effectiveness of the energy-efficient technologies recommended in the design package using the simple payback period method.Prescriptive packages of recommendations presented in the design package by climate zone include enhanced envelope technologies, interior and exterior lighting technologies, heating, ventilating, and airconditioning (HVAC) and service water heating (SWH) technologies, and miscellaneous appliance technologies. Final energy efficiency recommendations for each climate zone are included, along with the results of the energy simulations indicating a national-weighted average energy savings over all buildings and climates of 55.5% in comparison with the Standard 90.1-2004 as baseline.A cost estimate of the re...