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CURRENTS:
Building a New LEED

LEED 2009 looks to the future by standardizing the sometimes disparate LEED categories and providing a point model with more basis in hard scientific data

11/2008

By Nadav Malin

The U.S. green building council’s (USGBC) LEED rating system was a victim of its own success almost from the moment it launched. Overextended staff and hypergrowth led to spotty customer service and complaints from many users and stakeholders about a lack of responsiveness. But as LEED has matured, USGBC has gotten better at managing its success and focusing its efforts. Now it is ready with LEED 2009 (which until recently had the working title of “LEED version 3.0”), the most substantial restructuring of the LEED rating systems in the program’s history.

Building a New LEED

Building a New LEED

Image Courtesy U.S. Green Building Council

The point redistribution in LEED 2009 was based in part on this breakdown showing how important each impact category is relative to the others(top).

Point allocations in LEED for New Construction 2009 differ from those in previous versions mostly because USGBC deemed climate change the most important area of concern, and assigned more points to credits that aim to reduce greenhouse-gas emissions (bottom).

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Fundamentally, LEED 2009 is about aligning and rationalizing the various rating systems—LEED for New Construction, LEED for Commercial Interiors, and others. With LEED 2009, USGBC is getting its family of unruly ducklings in a row through “credit alignment”—revising similar credits in different systems to use the same language. This step also establishes a framework so that additional variations can be created to support more building types and special situations without demanding as much customized support in the form of unique systems, training courses, exams, and applications.

USGBC has also redistributed the points for all the rating systems and arrayed them on a 100-point scale, with 10 bonus points. This uniform point scale provides consistency across the various systems (which previously had a variety of point tallies), but underneath it is a more substantive development. For the first time, the number of points assigned to each LEED credit (each of which defines an action or performance level) has been informed by a scientific analysis of the benefits provided by that achievement.

This new weighted-point allocation system fulfills a promise made by USGBC president and CEO Rick Fedrizzi in 2006 to align LEED with the emerging imperative to address carbon emissions. It also applies environmental life-cycle assessment (LCA) to LEED’s point structure. USGBC’s first stab at this distribution is not perfect, but it establishes a framework that can be refined into something more rigorous over time.

USGBC staff worked with the various LEED committees and paid consultants to come up with a method for assigning points to credits based on the environmental or human-health value of each credit. To do that, they borrowed a list of impact categories from the U.S. Environmental Protection Agency, and drew connections between LEED credits and these impact categories. Credits for reducing energy use in the building, for example, are linked to benefits in the categories of greenhouse-gas emissions and fossil-fuel use.

USGBC’s next step was to decide how important each impact is relative to the others. This weighting of impact categories involves both science and value judgments. Eventually the organization hopes to engage its members in a broad-based effort to establish its own weightings, but for now it adopted weightings that the National Institute for Standards and Technology (NIST) established for its Building for Environmental and Economic Sustainability (BEES) life-cycle analysis software. Opinions differ as to whether the NIST process used the most sophisticated method or just smoke and mirrors, but the weightings that came out of that process are as good a place to start as any (see chart).

Once USGBC had decided how each credit affects each impact category and how important each impact category is relative to the others, it took just a few calculations in a spreadsheet to decide how many points should be assigned to each credit. But USGBC also took another step: just as you wouldn’t change all your holdings based on a single assessment to rebalance an investment portfolio, LEED is not switching over entirely to the science-based allocation. Instead, LEED 2009 has a point distribution that represents a hybrid of the old, intuition-based allocation and the new, science-based one. This hybrid recognizes that the science-based allocation isn’t yet sophisticated enough to factor in all the environmental and health benefits of various credits, much less the what-is-the-market-ready-for considerations that have made LEED such a hit in the industry.

Where is the science lacking? The life-cycle-assessment and other tools behind this weighting depend on many simplifying assumptions. For example, all the impacts were estimated based on a hypothetical 135,000-square-foot office building in a location with moderate heating and cooling loads. The impacts for any real building will be different. In the future, LEED might include a tool that rebalances the points for each project based on building-specific factors. Another simplification is that each credit is linked to one or more impact categories, but USGBC didn’t factor in how much benefit each credit has in each category.

Because of the importance assigned to greenhouse- gas emissions, the big winners in this process were credits designed to reduce energy use, both in buildings and from transportation. The credit in LEED for New Construction for access to alternative transportation went from one point to six, for example, and the two credits for energy efficiency and renewable energy together went from 13 to 26 points. Water conservation credits also benefited, going from 5 points to 10. These changes aren’t quite as dramatic as they sound, however—each point in the new system is only worth about two-thirds as much as a point in the old system because there are more points overall.

There are some changes to credit requirements in LEED 2009, but these are, for the most part, minor adjustments to make the different LEED rating systems more consistent with each other. For example, in LEED for Commercial Interiors (LEED-CI), project teams had the option of including plumbing products in their recycled content materials; however, this option was not available in the other systems. For consistency, it was removed from LEED-CI.

One credit that changed substantially was indoor water use reduction, where LEED 2009 requires 30 percent savings instead of 20 percent to earn the first point. Going even further, the 20 percent savings that used to earn an optional point became a prerequisite for all LEED construction projects.

Behind the scenes, USGBC is making other changes that will become more evident to users down the road. LEED 2009 will have an entirely new online application tool that will use online templates instead of PDF files to collect LEED documentation. And new rules will allow LEED committees to propose and apply ballot changes to individual credits without sending entire rating systems out for member ballot. Thanks to those new rules, a backlog of changes in credit requirements that USGBC held back from the 2009 update will likely begin appearing in 2011.

There is a lot one could quibble with in the details, but the overall move that USGBC is making with LEED 2009 is impressive in its scope and vision. More than anything else, it recognizes that LEED has to continue growing and changing to keep up with market demand and environmental and social imperatives. Now LEED has a platform that can better support that evolution.

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This article appeared in the November 2008 print issue of GreenSource Magazine.

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