Building energy efficiency has come to the forefront of political debates due to high energy prices and climate change concerns. Energy consumption in commercial buildings accounts for a significant proportion of worldwide energy consumption. In the U.S., commercial buildings consume 19% ofthe total national energy use and emit more than one billion metric tons of carbon dioxide . The demand for energy by the commercial sector is projected to increase by 1.2% per year from 2006 to 2030, driven by trends in population and economic growth . Due to this relatively large share of a nation’s total energy consumption, any increase in the energy efficiency of the energy systems for commercial buildings would result in notable energy savings and emissions reductions. Improving energy efficiency in new commercial buildings is one of the easiest and lowest cost options to decrease a building’s energy use, owner operating costs, and carbon footprint.