The green building findings by the University of California and the University of Notingham in the UK were published in the April issue of the journal Building and Environment. The researchers analyzed survey responses from 21,477 people in 144 mainly large office buildings primarily in the US.
Previous studies that reached different conclusions about worker satisfaction were based on much smaller sample sizes and different statistical tests.
The results found that factors such as buildings features, personal characteristics and conventional IEQ paramaters influence the difference in the satisfaction of workers in LEED and non-LEED certified buildings. However, the effect size of such variation is, for most, practically negligible, according to the study.
The research, conducted by Stefano Schiavon and Sergio Altomonte, found LEED-rated buildings with open spaces may be more effective in providing higher satisfaction than those with enclosed offices, in small rather than in large buildings, and to occupants having spent less than one year at their workspace rather than people who have occupied their workplace for longer. The findings suggest the positive value of LEED certification from the point of view of worker satisfaction tends to decrease with time.
The researchers say workplace satisfaction might improve of more design-related information could be collected by assessing LEED-certified buildings based on actual operations and performance. Currently, LEED certification is based on predictions without measuring real building performance post-construction.
The Environmental Policy Alliance released a report in March 2013 claiming large privately-owned, LEED-certified buildings in Washington, DC are actually less energy-efficient than their non-certified counterparts. The report found that weather-normalized energy use intensity for LEED-certified buildings was 205, compared to 199 for non-certified buildings.
The US Green Building Council, in a response to the report, contests that energy use intensity is a poor overall measure of a building’s efficiency. Energy Star ratings are a better measure of efficiency because they factor in a number of relevant metrics, the USGBC says. Using Energy Star ratings, commercial buildings in DC score in the 77th percentile nationwide for energy efficiency – and much of that is due to LEED.