SummaryHow occupants interact with their buildings needs to be a key consideration for all green building planning, design, operations and decision-making. Research on the performance of green buildings in recent years has placed greater emphasis on the need and opportunity to better understand the roles of occupants and the factors that shape their behavior, including default conditions, institutional frameworks, organizational culture, peer pressure and more. Understanding the relative impact of technology-based vs. occupant behavior-based strategies -and combinations of the two -is a key to learning how to make high performing green buildings commonplace.These questions are especially critical in the Federal building context, where ambitious sustainability goals require pushing green building performance to exemplary levels. These goals include the requirement that all new Federal buildings be designed to achieve zero fossil fuel use by 2030 (Energy Independence and Security Act of 2007) and the Army's Net Zero Installation program, whereby Army installations work to make entire bases so resource efficient that they will use net zero energy, water or waste by 2020.Fort Carson in Colorado Springs, CO is one of only two Army bases currently pledged to achieve net zero energy, water and waste. Its ambitious goals, and over 50 LEED-rated green buildings, make it an ideal site for a demonstration project on how occupant behavior may be leveraged to help buildings achieve net zero energy performance.This study, The Role of Occupant Behavior in Achieving Net Zero Energy: A Demonstration Project at Fort Carson, was sponsored by the U.S. General Services Administration's (GSA's) Office of Federal High-Performance Green Buildings (OFHPGB). The Office's mission is to facilitate the greening of the Federal building portfolio, by conducting applied research and demonstrations, developing standards, guidance and tools, and disseminating information. The Pacific Northwest National Laboratory (PNNL) partnered with GSA, the Department of Defense (DOD) and Department of Energy (DOE) in conducting this demonstration project at five green buildings on the Fort Carson Army base.The research focused on understanding the potential for institutional and behavioral change to enhance building performance. The research team identified specific occupant behaviors that had the potential to save energy in each building, defined strategies that might effectively support behavior change, and implemented a coordinated set of actions during a three-month intervention.The intervention focused on changing two occupant behaviors that had the potential to save energy: shutting down computers at night in the participating buildings, and setting back thermostats 5-10 degrees at night during heating season in the two buildings with decentralized heating/cooling controls.The behaviors were selected considering the specific context of each building, including the way occupants interacted with building features and estimates of the energy use impac...