LEED Buildings: How energy efficient are they??

So far in my career, I have been exposed to a few decent examples of the "way things really work" in the building industry. I've learned that building energy simulations and early design analysis can be tweaked to produce figures which will please the client all while staying within commonly accepted assumption boundaries. I've learned how and why the ignorance regarding the actual science behind green buildings is exploited as everybody rushes to jump on the bandwagon. And now, after stumbling upon the website created by a veteran in the building energy efficiency industry, Henry Gifford, I've begun to take a more critical look at my once flawless view of the LEED Rating System.

LEED is almost a household term these days after the US Green Building Council established it as the pioneering method for benchmarking the performance of buildings which fit the characteristics of good energy and environmental design. LEED has truly been a very successful program; the environmentally-conscious education of literally thousands of building industry professionals and construction of millions of square feet of new buildings has been guided by its good intentions. But now, it is becoming more evident that good intentions and solid marketing value of LEED is not enough to actually make a significant impact on the energy consumption of buildings.

A 2008 study that was prepared by the New Buildings Institute with funding from the USGBC and the EPA shows that the median of the 121 LEED Buildings tested perform at 24% better than than the national mean of US Building stock. Sounds great, right? Well, a more critical look by Mr. Gifford exposed flaws in the way the data was presented which shows actually that LEED buildings perform worse when the mean of their values of consumption is compared to the mean of the recently constructed building stock (2000-2003).  The "gist" of this contradicting study can be found from Henry's presentation at the Westford Symposium for Building Science:

This must be embarassing for the USGBC - however they need to stop getting defensive about it and take it as a call to action to make the system more legitimate! I think in many ways this is occuring based on a press release sent out to USGBC members on Sept 25. In it they say that they are "Tackling Building Performance Head On!!". This sounds very hopeful in my opinion however it must be done right in order to be effective. The building owner and maintenance personnel must truly be held accountable for the energy performance of the building and as Henry eloquently states "the plaque should be attached with removable screws".

A very thorough paper outlining Gifford's approach to rating buildings can be found here.