April/May 2009
Energy Efficiency
C O N T E N T S
Colorado Biz: ColoradoBiz Profit Report, By Deb Kleinman, USGBC CO Executive Director
Partner Events: Colorado Real Estate Journal's 2010 Green Building Summit and Expo, By Deb Kleinman, USGBC CO Executive Director
Scholarship: Greg Franta Memorial Scholarship Fund , By Clay Benson, Mortenson Construction
LEED ND: City of Aurora Sets a New Standard for Sustainable Development, By Patti Mason, USGBC CO Director of Advocacy
CMP: "How do I Find LEED-Specific Continuing Education Hours?", By Jessica Pascoe, USGBC CO Director of Education
Rocky Mountain Green: Calling all Green Building Experts!
Membership Highlights: Mike Vail of Water Legacy, By Patti Mason, USGBC CO Director of Advocacy
Natural Talent Design Competition: And the Winners Are..., By Sarah Michaels, USGBC CO Chapter Coordinator
Colorado Building Green is the official newsletter of the U.S. Green Building Council – Colorado Chapter, and is published bi-monthly. If you are interested in submiting a story, ideas or other information for publication, please contact the editor at sarah@usgbccolorado.org
LEED Buildings and Energy Efficiency: Are Intentions Good Enough?
By Mark Stetz, P.E CMVP, Principal of Stetz Consulting LLC
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 daylighting, 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.
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