Preface by Grant:  This is a new piece by IGP Fellow, Mark Stetz.  If you are attending Greenbuild in Phoenix, he will be teaching Building Performance Verification - drop by and say hello.  The topic of a disparity between LEED building performance expectations and the reality of its performance is relevant to everyone in sustainable development because it has the potential to impact client/owner satisfaction with the project, occupancy, lease rates, marketability, and value.  Additionally, it has the potential to become a professional liability or "standard of care" issue/dispute.

USGBC Addresses Performance Anxiety
by Mark Stetz P.E., CMVP FIGP

In my last article, I discussed how LEED-certified buildings might not live up to expectations when their performance is objectively evaluated. While newly constructed LEED-certified buildings are designed to be energy-efficient, design intent is not always realized in the construction and commissioning phases. Frankel & Turner [1] showed that despite good intentions, about 20% of the LEED-certified buildings in their study didn’t perform to code.

The USGBC has been aware of this problem for some time, but now the LEED community and to some extent the general public are also aware of the ‘performance gap’ between expectations and achievement. The release of LEED 3.0 attempts to address this issue by doubling the available points for energy efficiency, raising the threshold against which savings are based, placing added emphasis on measurement & verification, and instituting minimum program requirements (MPRs) that will allow USGBC direct access to utility bill information. Yet the LEED certification process remains fundamentally an intent-based system. 

 Rather than sequestering itself in back rooms and issuing directives, the USGBC is using an open process of soliciting feedback and ideas for improving the LEED program. The Building Performance Initiative committee (BPI) held five meetings across the country and invited stakeholders – developers, owners, architects, and engineers – to discuss the current New Construction certification process. How might it be improved so that LEED certification actually indicates something more than good intentions?

I attended the Washington D.C. meeting where discussions revolved around whether New Construction certification should use design-based or performance-based methodology.

In a performance-based system, certification would be granted after occupancy and utility bill evaluation show that the building actually met design intent. One path is to grant conditional certification based on design and final certification based on performance. Another would be to require annual updates based on performance similar to the Energy Star program. The last would be to have buildings certified under the New Construction program enroll in EB/OM.

Before an actual methodology can be developed, the USGBC and building community still have to decide if New Construction certification should continue to be designed-based or make the leap to performance-based. One proposal – although discussed in somewhat facetious terms but with an element of truth to it – is to make the LEED plaque removable [2]. However, no one volunteered to be the person with the crowbar.

If the USGBC were a democracy, a performance-based approach would have passed by a wide margin with the Washington crowd, but regions. The San Francisco meeting was unanimous in wanting a performance-based system and they wanted it yesterday; the New York meeting wanted nothing to do with performance verification - so we were told - and felt design intent was sufficient.

Interestingly, the minimum program requirement of utility-bill access was seen by some owners/developers as being necessary, others felt it to be a deal-breaker and would walk away from LEED certification rather than allow outsiders access to their records. To his credit, Brendan Owens the USGBC's VP of Technical Development, stated he’d opt to lose potential participants rather than sacrifice program credibility.

Marcus Sheffer, head of the Energy & Atmosphere Technical Advisory Group (EA TAG), spoke regarding pending changes for LEED 2012 and how best to address the performance gap. He believes the role of building modeling should be to evaluate design alternatives, not to try to predict actual building performance with high precision.  Additional questions being addressed include identifying the proper metric to evaluate building performance – is energy use intensity (EUI) the right number, or should a building be evaluated based on energy cost, source energy, carbon dioxide emissions, or some combination of these? The ASHRAE 189P committee is struggling with this same issue.

Identifying an appropriate baseline and threshold will make a difference in the starting point against which savings or performance is compared. To improve the potential for performance verification, alternative compliance paths for EA5 (Measurement & Verification) are being considered.

Other barriers to translating intent into performance include architects who are primarily concerned with  aesthetics and functionality rather than building energy use, the lack of a feedback loop between those who pay the utility bills and those who operate the buildings, and contractual or legal barriers that add unnecessary roadblocks.

As an example of potential legal obstacles, the city of Arlington, VA, now requires all new buildings to seek LEED certification as a condition of occupancy. Requiring a performance review would put their buildings in a Catch-22 situation: a certificate of occupancy requires LEED certification; LEED certification would require occupancy and performance evaluation. Which will come first?

The fundamental question being asked is: do buildings that don’t achieve their design intent have the right to claim LEED certification? Some argue that yes they do, since LEED certification is recognition that the design is superior to other buildings, but there were several different proposed methods to make certification conditional or even revocable.

Toward the end of the meeting, Scot Horst explained that the Building Performance Initiative is USGBC’s effort to improve LEED and make it a more useful tool. By collecting utility information on a larger sample of buildings, it is expected that stronger conclusions can be drawn about where the disconnect between intent and performance lies. Unfortunately, conclusions alone are not sufficient. By improving our understanding of the differences, USGBC and ultimately the members of the building community will be in a better position to take action and improve building performance.

Tom Hicks – head of the BPI- asked those present if there were one thing we could do to improve the process and close the performance gap, what would that be? If you have suggestions, please feel free to use the ‘comment’ section of this blog.

The final BPI meeting will be held Friday morning (11/13) at Greenbuild to summarize what the USGBC learned from five different meetings and what actions it will recommend.

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 and  can be reached through http://www.stetzconsulting.com.

1. Energy Performance of LEED® for New Construction Buildings, Cathy Turner, Cathy; Frankel, Mark, New Buildings Institute May 2008 http://www.newbuildings.org/measuredPerformance.htm

2. A Better Way to Rate Green Buildings, Henry Gifford 2009, http://www.EnergySavingScience.com