LEED Buildings Flunk Targets
Thursday, August 6, 2009 at 2:36PM Grant's Preface:
OK, it is a bit of a teaser heading with a factual basis, but Mark Stetz provides a compelling case for why "good intentions" are not enough for high-performance buildings.
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 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.
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 Institue 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
http://www.newbuildings.org/measuredPerformance.htm
3. Do LEED-certified buildings save energy? Yes, but...
Newsham, G.R.; Mancini, S.; Birt, B.
National Research Council Canada
NRCC-51142 August 2009
https://www.nrc-cnrc.gc.ca/eng/projects/irc/post-occupancy.html
4. A Better Way to Rate Green Buildings
Henry Gifford 2009
http://www.EnergySavingScience.com
5. Personal communication with Brendan Owens, USGBC 2009.
Reader Comments (17)
As LEED buildings rise in popularity, best practices and certification point risk areas will come to light, just as "low hanging fruit" points did some years ago.
Some culprits I have experienced include:
1. Lack of centralized leadership and knowledge center for the LEED project
2. Overlooked certification points in the areas of infrastructure and common amenities
3. Contractor management of the construction process, especially the documentation requirements for waste and indoor air quality (IAQ)
4. Team members lack authority to effect change or implement inspector/commissioning agent recommendations
5. Loss of design points due to missing documentation or improperly completed forms
6. Subcontractors’ unfamiliar with LEED
7. No LEED training for contractors and subcontractors, focusing on topics such as materials separation, erosion/sedimentation control, and IAQ protection of materials (including designated smoking areas)
Posted by Alexia Nalewaik, CCE MRICS MSc
It is important to highlight and discuss failings to afford change.
I have a minor concern for load bearing structural materials possibly not the best for sustainability due to long term wear and tear data.
Intentions are a start, not a solution. LEED helps
When Coca-Cola starts and add campaign featuring a grid independent bottler, I am sure more of us will accept Coke being more expensive than beer in many countries :)
Posted by Ken Nakagama
Great, very informative and frank article. Thank you for the posting. I like the good intensions of LEED participants, but the quesions is: what better incentives can be provided for long-term and real building compliance?
Posted by Orit Reuben
I've heard rumbling of weakness within the USGBC LEED certification program, but I've never read anything in black and white (proof). Thanks. I hope, as the author suggest, LEED v3 is a step in the right direction. Otherwise the commercial market will turn its back on the process and the skeptics win.
Chris
"Designing" and "living/working with" are two different things. This has been one of my biggest frustrations over the years with performance models. Real people don't behave like computer simulations (at least, not most of the time).
I always tell people looking for ways to "go green" to make it as simple as possible so that you are more likely to engage in the desired behavior. Making daily decisions that minimize energy use is a lot like dieting or an exercise program. People tend to be very "fired up" at first and compliance is good, but as time goes on, they get more lax. Or, I would anticipate in this case they may even expect the building to do the work rather than the occupants (after all, it's a LEED certified building, not LEED certified occupants).
I live in a passive solar home. In my experience, a "passive home" requires an active homeowner to achieve optimal performance. Maybe this is part of what is coming to light with this study?
Great article. I completely agree. If we don't evaluate what works, what doesn't, and why, we risk repeating mistakes, wasting resources, minimizing the quality of our experience within the built environment and giving "Green"/LEED a bad name. Such evaluations must also include a systematic analysis of the occupant/building interface, looking at the relevant human physiological, psychological, and social/cultural factors, and how they impact both the building's performance as well as the occupant performance and general well being. I do think that LEED 2009 is an improvement over past versions, but it needs to go farther, particularly with regards to human factors. Anthropological/sociological/ethnographic methodologies and theoretical frameworks should be required components of these analyses - something that the firm I work for promotes: http://www.megroup.com/index.php/green/human-inquiry.
I've written a similar article on this for Science Progress: "Every Building is an Experiment" - http://www.scienceprogress.org/2009/03/every-building-is-an-experiment/, as well as lectured on this. One of which can be seen at http://www1.unl.edu/mediahub/media/726 (Keeping Green Buildings From Turning Brown).
Yes, the buildings may have been built to LEEDs standards, but what the owners and tenants do inside can change the whole carbon footprint. Kathy Turner, author of the LEED performance study, and it was based on the 100 or so out of 520 buildings built up to 2006. The results of the 12 months of utility data were pretty much all over the place. Warehouse were low in usage, office buildings middle, and data centers (phone centers, high tech and labs) were very high in electricity usage.
The green movement needs credibility, and is utilizing the support of ASHRAE and considering Net Zero buildings in the future.
Posted by John Turner
There needs to be clarity over what LEED actually is. In the UK we have BREEAM, which is a similar approach, and suffers similar problems. The focus currently is on assessing the projected performance of the design. This is based on operational assumptions, the most significant being that the users occupy the building for a set purpose and time profile, and will operate the building and its systems efficiently and effectively.
Until these processes (LEED, BREEAM etc) have a substantial - I would suggest equal - weighting to in-use assessment, they will remain largely aspirational statements of design intent, and little more. There is a method for assessing buildings in use under BREEAM (not sure if LEED offers this), so it would seem logical that for certification, there should be a need to link the two processes - ie a building has a "Design Rating" and an "Operational Rating".
The Design Rating is simply the 'statement of design intent' we currently have and use, and is pretty much a marketing tool - however the fundamental underlying assumptions on building usage patterns should be a part of the rating. Perhaps the metrics should be shifted towards working time rather than annualised - W/m2/work hour (btu/ft2/work hour) or similar.
The Operational Rating is the one that could add real value to building users, as it would allow them to asses firstly performance against design, secondly their operational performance in managing their building asset, and finally identify areas where they could secure cost benefits through operational improvements. And surely that is what the desired output of this process really is, rather than some pointless "my building design is more green than yours" competition.
Identification and demonstration of the disconnect between the design aspiration and the built reality is, I suppose, the first necessary step for bodies corporate to start joining the dots.
Posted by Eric Hutcheon
One of my major complaints with LEEDS is its lack of recognition of existing circumstances.
Example - A company in an existing office space in an area with a 25% vacancy rate builds a new building 12-15 miles away from it's employees "center". They get a LEEDS certified building by building in a green field, even though there was more than ample existing space available within a 5 mile radius of the existing office. Not only were a lot of resources used in the construction of the new building and the land that was turned from green field to impervious structure and parking lots, but the majority of employees ended up having to drive an extra 24-30 miles a day.
They received LEEDS silver, but it was an overall a far greater increase in energy and resources used.
Posted by Paul Fritz
It is important to understand that LEED is just a simplified tool that in no way can match the complex realities of sustainable building performance. The great success of LEED is not certification of buildings, but the acceptance of some kind of standard and an awareness about performance that serves as a starting point. Since LEED was first implemented, the green building movement in the US has become increasingly sophisticated. Now there are myriad daylighting and thermal performance software tools, product manufacturers offer much more information on their products, and so on. Slowly but surely, we will eventually get down to the real-time analysis; but we need to take it one step at a time. Europe is still way ahead, but we're quickly approaching...
Posted by DEN Architecture
thanks
wish there were more comments -- did anyone read ECOLOGICAL DESIGN 1996.....?
Posted by sven alstrom aia
The Mark Stetz blog covers the issue very well. I also had the good fortune to hear Cathy Turner, co-author of the original study, present her findings in a webinar sponsored by Pacific Gas & Electric. She raised a good point: did the buildings fail or did the energy modeling fail in the design phase?
Posted by David Adams
Some very good points made in this article and a good reality check for building owners! Just as life-time cost of ownership is most dramatically impacted by energy efficency measures; follow-through with continuing operations is the real challenge to actually achieving long-term sustainability. That is why training and operations proceedures and manuals are so important.
Posted by Lance LeTellier, PE
As a roofing contractor I see many instances where you trade off performance for green roof systems with low VOC. While the manufacturers are working on it, they are not there yet.
Posted by Doug Plotke
The author's observations make a case for re-certifying LEED Buildings under LEED-EBOM which requires ongoing monitoring and evaluation of systems performance. LEED certification should not be a static and singular event but a long-term commitment.
Posted by Joanna C. Rodriguez, AIA, LEED AP
this is a really good point- having started in the 70's with superinsulationand worked throu zero energy and net zero - a couple of hundred times- we can certify that the least consistent installed component of any home is the owner. Our early homes were blower tested on completion and once every 6 years and a few are still tested now- oldest one in the testing program is now 31 years old - technically the envelope has survived exceptionally well- highest infiltration has been 0.14 NACH- great results through a number of door sill replacements etc- energy performance varies with the mood and perserverance of the occupant. Once we got this good at envelopes- operating NH non-generating houses all electric at $28.00 a month all year long- we discovered that the occupant was the biggest wild card.
Posted by Kricket Smith-Gary
Thanks for the article. It shows one fragile point of LEED certification program in the sense of its inability to address the long chain in the fragmented Construction and Real State industries: from plan and development, design and build to the impacting O&M stage. It partly reflects the difficulty found in this markets for any initiative. The first stages are well addressed by LEED while in the M&V Plan's implementation it looses impetus. M&V when actually implemented can be a tool to keep track of building's performance even over its lifespan. It also can be a natural link to LEED-EB.