To examine whether green buildings deliver their promised performance, the U.S. General Services Administration (GSA) conducted a study of 22 representative buildings from the administration’s portfolio. Each building was evaluated on its environmental performance, financial metrics, and occupant satisfaction. The overall results show that on average, GSA’s green buildings use less energy and water, have lower carbon dioxide (CO2) emissions, cost less to maintain, and have more-satisfied occupants.
Of the 22 buildings in the study, 12 previously had their performance assessed in 2007. All buildings in the study incorporated sustainable design, and 16 were LEED-NC certified or registered. The study was conducted in two phases and results were compared to both industry and GSA baselines. In the first phase, which was completed in 2008, the GSA developed a repeatable, post-occupancy evaluation methodology that was piloted across the 12 buildings mentioned above. In the second phase of the larger study, the first 12 buildings were reexamined and 10 additional buildings were added to the sample. Data in the study is primarily from 2008 through mid to late 2009, and addresses Energy Use Intensity (EUI), energy cost, CO2 emissions, maintenance costs, occupant satisfaction, and water use.
Key findings include:
The buildings in the study use 25 percent less energy compared to national averages, tracking at 66kBtu per square foot versus 88kBtu per square foot. In addition, the GSA’s LEED Gold–certified buildings in the study have a 27 percent lower energy use (52kBtu per square foot).
The buildings in the study have aggregate operating costs that are 19 percent lower than national averages, at $1.60 per square foot, rather than $1.98 per square foot.
The buildings in the study have a 27 percent higher occupant satisfaction rate.
The buildings in the study have 36percent fewer CO2 emissions than the national average.
The full white paper can be viewed and downloaded at gsa.gov/graphics/pbs/Green_Building_Performance.pdf