4 FM quick reads on LEED
1. LEED in Motion Report Provides Evidence of LEED Buildings' Efficiency
Today's tip of the day is about the third LEED in Motion report that provides evidence that LEED buildings are more efficient than traditional.
The third LEED in Motion report — this one titled Impacts and Innovations — was released at Greenbuild 2013, and among its fascinating statistics (85 percent of LEED-EBOM certified buildings achieve the green cleaning credits), the report reveals details of a new study.
Between July 2012 and July 2013, USGBC analyzed more than 450 LEED certified projects, and determined that the projects, on average had an energy use intensity, of 31 percent lower than the national average. What's more, 404 of the 450 projects had an Energy Star score of 85 or higher.
That seems like pretty clear evidence that, for the most part, LEED buildings are, indeed, better performers than their non-green counterparts. Data continue to flow in — and USGBC is hammering home the point that they're continuing to collect and analyze data — but it seems increasingly clear that at least one of the major criticisms of LEED (that's its buildings are the same as traditional buildings) is baseless.
Energy Modeling: What Happens When You Make Bad Assumptions?
Today's tip is about energy models, and the notion that they're only as good as the data put into them — that is, how close to reality the assumptions are made at the start of a project. In other words, the quality of the input data is ultimately what determines how useful the output data is. This is an especially cogent principle when it comes to an energy model, as the fewer assumptions the engineer doing the model must make, the more reliable the energy model will be.
The facility manager must have an open, honest discussion with the design team at the very beginning of the design process to make sure everything and everyone is on the same page. The information derived from this meeting - or more likely, these meetings…plural - will improve the quality of data input into the model. Inputs include window to wall ratio, tightness of air infiltration, thermal wall and roof insulation, performance criteria of glass, type and efficiency of mechanical system, lighting type and expected watts per square foot, plug loads watts per square foot, and occupancy.
Of course, there will always be some variables that are impossible to predict. The occupancy of the building may be greater than expected. The building's operating hours may be longer than expected. Equipment may not interact as expected. Even so, an energy model is still an essential (and if you're doing LEED, required) part of the construction process.
How many times have you heard that a LEED building is supbar because it used slightly more energy than its energy model predicted? That doesn't mean it's a bad building! After all, an energy model isn't intended to be a totally accurate predictor of the precise amount of energy used. That's what measurement and verification are for after the building opens. After building systems are commissioned, facility managers must measure and verify from the second the door are open in order to find anomalies and fix issues that may arise.
What Can We Learn From LEEDs Critics?
Today's tip of the day is about what we can learn from LEED's critics.
Oftentimes, the natural response to criticism is to get defensive, dig in your heels, and then counterattack. But that is usually less productive and more polarizing. To avoid such a reaction and instead open a dialogue is the key finding common ground and moving forward.
With that in mind, one of the more fascinating sessions at Greenbuild 2013 was titled "What We Can Learn From LEED's Critics." The session, presented by Tristan Roberts of BuildingGreen, Rob Watson of ECON Group (and who carries the "Father of LEED" moniker), and Pamela Lippe of E4 Inc., broke LEED criticisms into three main categories, and then examined the validity of each, and how USGBC has responded.
The first criticism is that the LEED process is broken - this covered both the rating system development process, as well as the certification process. To address the first, USGBC says it has maintained an open, iterative process to the rating system development process, as evidenced by the more than 20,000 public comments over six comment periods, and then the 86 percent approval when LEED v4 was put to a vote. They've also drastically cut down on the time between submission and certification — 85 percent of projects are ruled on within 25 days of submission. That's a vast improvement.
The second criticism is that LEED is not vigorous enough. You hear this one a lot from the vocal critics who say a LEED certified building isn't any better than a traditional. USGBC is working diligently to compile more LEED data — now requiring all LEED registered projects to submit five years of water and energy data — to show that LEED buildings are, indeed, more environmentally responsible than traditional. During this discussion, Rob Watson unleashed the quote of the conference: "If your building isn't performing, it's your fault. Not LEED's." How true.
The third criticism is that LEED is too complex and too expensive. You commonly hear this from folks who think LEED certification is simply "buying a plaque" and that the constant updates to LEED make it impossible to keep up. No one would deny that LEEDv4 is a giant step forward in terms of rigor, but that's what is needed to move the market, says USGBC. And as for "buying a plaque," reasonable minds can disagree on the value of certification itself, but USGBC has always said that a third-party review is what really motivates projects teams to stay the course and follow through.