Two recent studies of LEED-certified and Energy Star-rated commercial buildings show the benefits of these buildings versus their non-rated counterpoints.
Buildings certified under the LEED-NC (new construction) standard, "average substantial energy performance improvement over non-LEED building stock," according to the study conducted by the New Buildings Institute for the U.S. Green Building Council (USGBC). The study looked at the performance of 121 LEED-NC certified buildings, 22% of all such buildings.
In terms of Energy Use Intensity (EUI), the LEED buildings performed 24% below (better) than the national average of all commercial building stock. For offices, the most common type, LEED EUI's were 33% below the national average.
The Energy Star ratings of the buildings were also superior. The average Energy Star rating of LEED buildings was 68 (meaning better than 68% of similar buildings) compared to the median rating of 50. Nearly half of LEED buildings had Energy Star ratings of at least 75.
LEED buildings also performed as forecast by the energy usage modeling encouraged by the LEED program. Measured energy savings for the buildings in the study averaged 28% compared to code baselines, close to the average 25% savings predicted by energy modeling in the LEED submittals.
However, superior energy performance was not universal among LEED buildings. "Within each of the metrics, measured performance displays a large degree of scatter, suggesting opportunities for improved programs and procedures," the report declared.
A second study, "Does Green Pay Off," compared the performance of Energy Star-rated buildings vs. non-rated buildings to determine the benefits of investments in energy savings and environmental design. Energy Star-rated buildings had higher occupancy rates, higher rental rates and rented for more per square foot than non-rated buildings, the study found.
Operating expenses for rated buildings were also lower--$1.27 per square foot per year versus $1.81 for energy in 2006.
"Together, the higher occupancy rates, higher rents and lower operating expenses translate to significantly higher values," the report states.
Many benefits have yet to show up, the study added, because building tenants are the beneficiaries and they want proof of performance before they are willing to share in the cost of energy saving investment. Broader understanding of the benefits among tenants is likely to translate into higher rents and therefore higher building values, the report adds. The study was conducted by CoStar, a real estate information company, and a professor at the Burnham-Moores Center for Real Estate.