I have been spending a lot of time recently thinking about two posts I made regarding the LEED 25 percent premise and why this will be problematic for green building mandates.  Why did I reconsider these posts?  Rob Watson told me I was wrong. 

Watson knows LEED better than you and I.  He was one of the original members of the USGBC.*  When he tells you your post about green building "does not add up", you listen.  Watson made some great points that I would like to share with you. 

The general premise of my post was that the USGBC intends for only 25 percent of the building stock to attain LEED certification.  As more cities mandate LEED certification, which requires 100 percent compliance, some projects will fail to achieve LEED certification.

Watson was kind enough to explain the 25 percent premise to me in more detail.  In short, it is not as simple as adding up all the building stock, determining how much new stock achieves LEED New Construction certification and coming up with a percentage.    This was the incorrect equation floating around in my head:

Here is how Watson describes it: 
    The 25% guideline (and again to emphasize that this is as much a figure of art as it is of science) refers to each individual market, so once a project ‘graduates’ from the new construction classification, it goes into the existing building classification. Thus, the 25% of new construction floor area gets significantly diluted once it becomes part of the much larger EB base.
Based on this description, it is now clear to me that the 25% guideline would only apply to new construction starts, not the entire building stock.  Here’s the simplified equation:

I am less concerned about the 25 percent premise from a risk and liability standpoint after Watson’s clarifications.  My primary concern was that very soon, 25% of the total building stock would achieve LEED certification and that the USGBC would have to make significant revisions to reduce the number of certifications occurring.  Since the 25% guideline is only measured in terms of new construction starts, the percentage will fluctuate up and down from year to year. 

Of course, LEED is under continuous improvement and increasing stringency in part to ensure that the system is dynamic and market leader and to disseminate best practices as rapidly as possible.  But the massive overhaul of LEED that I feared does not appear to be on the horizon. 

*To be clear, Watson was speaking to me as the CEO of The EcoTech International Group.  He was not speaking on behalf of the USGBC.