Monday, September 21, 2009

Where do good intentions LEED again?

Mark Stetz a fellow EVO-ite gave me permission to repost his complete article that he wrote in preparation for a class he is teaching at Greenbuild.  The article already appeared at, but I thought it would be of value to our readers as well.
The article address one of the main shortcomings of the LEED certification that I have continued to hear since I joined the energy industry.
Buildings and Energy Efficiency: Are Intentions Good Enough? by Mark Stetz, P.E., CMVP, FIGP
One of the benefits claimed for LEED-certified buildings is their reduced energy use, resource consumption, and carbon footprint relative to their peers. Designing a building to be energy-efficient, take advantage of solar energy and day lighting, use emerging technologies, and using a commissioning agent seems like a good way to lower energy and resource use. Achieving design goals requires that specialists from many different disciplines work together in a harmonious relationship, but the greatest danger to any relationship is failed expectations.
The LEED rating system scores buildings by assigning points based on land, material, water, and energy use over a building’s lifetime. One of the weaknesses of the LEED system is that points are based on design intent and not verified performance. For years, the USGBC claimed that LEED-certified buildings used less energy than the average building, although they had little supporting evidence. This claim was based solely on expectations of superior performance. Critics were quick to argue that the point- and expectation-based rating system would not result in well-designed cost-effective buildings. [1]
The USGBC – partly out of curiosity, partly in response to its critics – commissioned a study to investigate how LEED-certified buildings actually operate rather than rely on how the designers and builders think they operate. The 2008 study by Frankel and Turner [2] showed that design intentions are unfortunately often not realized. Of the 552 LEED-certified buildings in existence at the time, only 121 had utility data available for review. Of those 121 buildings, 40% did not meet their energy target and more than 20% had energy use intensities greater than code requirements! While debate continues over the validity of the statistical and evaluation methods used, the report suggests that over half of the buildings met or exceeded expectations. But for a program that emphasizes energy efficiency as one of its key attributes, how is it that 20% of these buildings did not even perform up to code?
For conventional buildings, code-compliance is based on design intent rather than post-occupancy verification. Since the Frankel & Turner study did not evaluate individual non-LEED buildings, it is not possible to show how many conventional buildings live up to their design intent. Additional analysis of the same buildings conducted by National Research Council Canada [3] reached similar conclusions, with the good news that on average, LEED buildings do save energy but that individual buildings may not. But no one occupies the average building any more than they have the average 2.3 children.
In an attempt to address some of the weaknesses with LEED 2.2, LEED 3.0 – released April 2009 – further emphasizes designing for and achieving energy reductions. The point system has been revamped to make it align more with the USGBC’s goals of energy and carbon reductions. Energy efficiency (EA-1) can now earn a building up to 19 points and the Measurement &Verification credit (EA-5) – which validates energy use - is now worth 3 points. To enable additional post-evaluation research, USGBC will require post-occupancy access to the water and energy bills, access that needs to be maintained even if the building changes owners. Although some critics have suggested that certification be revoked if an individual building ever fails to live up to its claims [4], the USGBC has not yet taken that draconian step.
Lessons learned from studying existing buildings – LEED and non-LEED alike – support the continued integration and cooperation of disciplines when designing, constructing, and commissioning buildings so that they work as a system rather than a collection of parts. They also show that performance monitoring during the life of the building is equally important. Only 25% of LEED-certified buildings apply for and receive the M&V Credit EA-5 [5], possibly because there are easier and cheaper ways of earning points. Unfortunately, receiving the M&V credit only requires writing an M&V plan; there is no requirement that it be implemented. The expectation that someone will carry out the M&V plan will continue to be a weakness with the LEED system.
Benefits of building performance monitoring include not just cost control and the ability to claim carbon emissions, but also feedback for the designers and operators to apply to their next project. Building simulation models may appear reliable because they are done on a computer, but many building characteristics are unknown and unknowable, so assumptions are used instead. For example, a building may be designed as a 9 to 5 office building but the tenants actually operate 24/7. The resultant energy use will be significantly greater than originally estimated, but with no real verification, it would appear that the building is less efficient than intended. In this case, the assumed occupant behavior does not match reality. Only by verifying the actual energy use and comparing it to the models can assumptions and building performance can be validated.
If LEED-certified buildings are to live up to their expectations, performance cannot be based on design intent. Hope is not a plan. The goals of energy, cost, water, and carbon reductions need to be demonstrated in practice if the LEED program is to maintain credibility. The new LEED 3.0 requirements are a step in the right direction; the rest is up to those who design, build, commission, and occupy buildings. 
About the author
Mark Stetz, P.E. CMVP, FIGP, is the Principal of Stetz Consulting LLC and an energy engineer specializing in building performance verification and energy audits. He will be teaching Building Performance Verification at Greenbuild in 2009 and Measurement & Verification at the ASHRAE Winter Meeting in 2010. Mark is also on the Advisory Board of the Institute of Green Professionals.
1. LEED Scores Early Successes but Faces Big Challenges
E Source Technical Brief ER-04-3
Platts Research & Consulting 2004
2. Energy Performance of LEED® for New Construction Buildings
Cathy Turner, Cathy; Frankel, Mark
New Buildings Institute May 2008
3. Do LEED-certified buildings save energy? Yes, but...
Newsham, G.R.; Mancini, S.; Birt, B.
National Research Council Canada
NRCC-51142 August 2009
4. A Better Way to Rate Green Buildings
Henry Gifford 2009
5. Personal communication with Brendan Owens, USGBC 2009.
Nathan Shetterley (
EVO Director of New Media