Energy efficiency (i.e., the ratio of output of performance to input of energy) in office buildings can reduce energy costs and CO2 emissions, but there are barriers to widespread adoption of energy efficient solutions in offices because they are often perceived as a potential threat to perceived comfort, well-being, and performance of office users. However, the links between offices' energy efficiency and users' performance and well-being through their moderators are neither necessary nor empirically confirmed.

People spend most of their time inside buildings, and buildings are responsible for approximately one third of total direct and indirect energy-related worldwide carbon emissions. Likewise, buildings in the U.S. account for about 40% of total U.S. energy consumption. Future building development will be driven not only by emerging challenges such as vulnerability to a changing climate and resource scarcity, but also by disruptive innovations and societal changes.

The built environment accounts for approximately forty percent of the total energy consumption in developed countries. Because buildings have a long life, the greatest opportunity for energy reduction in the built environment will come from energy conservation in the existing building stock. An overview of the policy challenges presented by the built environment, with an emphasis on existing facilities, is accompanied by a discussion of specific technologies that may have the potential to reduce energy use.