But two studies released this fall added a sour note to the clarion call. At the beginning of November, Greener World Media issued a report by Rob Watson. The editor of GreenerBuildings.com, Watson is renowned for developing the USGBC’s Leadership in Energy and Environmental Design rating system (popularly known as LEED). Watson’s report included impressive data on market trends, land impact, and water efficiency for LEED projects. When it came to energy savings, though, the numbers were discouraging. “Some LEED buildings are not performing as expected given their design and technology elements,” Watson stated bluntly. “This is an area of controversy and a source of great attention by the U.S. Green Building Council.”

Another report—released at the end of October by the USGBC’s Chicago chapter and its partners—put a finer point on the problem. The study looked at the median efficiency of LEED-certified buildings in Illinois and found that they were performing only 5 percent better than their non-LEED counterparts throughout the region. Fewer than 30 percent of the buildings were eligible for the government’s ENERGY STAR label. And the Platinum and Gold LEED buildings were no more efficient than those that had Silver or basic LEED certifications.

Given all the buzz and optimism surrounding green buildings—and the meticulous detail of the LEED rating system—these findings might seem puzzling. But they make more sense up close. Anyone seeking LEED certification can choose from a menu of eco-friendly credits. Instead of selecting energy-minded features like efficient mechanical systems, developers often reach for the low-hanging fruit. They might use paints that have low levels of volatile organic compounds or install cabinets made from rapidly renewable wood. They may opt to recycle their construction waste or increase airflow throughout the building. All of these choices fulfill the “Environmental Design” half of the LEED bargain, saving trees and improving the quality of human life, and many of them help minimize pollution during the construction phase. But none of them prevents an occupied building from guzzling fuel and pouring greenhouse gases into the atmosphere for years to come.

When the Illinois study looked at cases where engineers had taken the time to labor over sophisticated energy models, it found that 75 percent of those buildings fell short of expectations. The fault presumably lay with building managers who made numerous small mistakes—overheating, overcooling, misusing timers, miscalibrating equipment. The buildings’ owners, with LEED banners already hanging in their lobbies, had little incentive to demand better day-to-day performance. At a building science symposium in Westford, Massachusetts, former heating systems contractor Henry Gifford roundly criticized the USGBC for letting LEED recipients rest on their laurels in this way. “They don’t have to do a good job,” he noted, “because nothing they do will screw up the greenness of that building.”