US buildings consume roughly 40% of the nation’s primary energy and are responsible for a similar fraction of our greenhouse gas emission. There is tremendous documented potential for lowering both of these figures through cost-effective energy efficiency improvements in buildings. Green building rating systems such as ENERGY STAR and LEED represent national efforts to realize these savings. But what do the data tell us about their success in reducing building energy consumption and greenhouse gas emission. Because building energy data are the property of building owners energy performance data are limited. What little data we have shows us that 1) there is a huge performance gap between a building’s predicted energy consumption and its measured consumption. I will discuss site and source energy and show that, from what little data we have, on the whole green buildings are not saving significant primary energy. Specific problems with LEED and ENERGY STAR ratings will be discussed, along with some ways to correct the situation.