Leadership in Energy and Environmental Design (LEED) is an independent, third-party green building certification system that promotes sustainable building and development practices by defining and measuring “green buildings.” In March 2000, LEED was developed by the U.S. Green Building Council (USGBC), a nonprofit organization committed to a prosperous and sustainable future through cost-efficient and energy-saving green buildings.
The USGBC’s mission is “[t]o transform the way buildings and communities are designed, built, and operated, enabling an environmentally and socially responsible, healthy, and prosperous environment that improves the quality of life.” 1
LEED is one of USGBC’s preeminent programs developed to provide building owners and operators with a framework for identifying and implementing practical and measurable green building design, construction, operations, and maintenance solutions.
LEED has become the common benchmark for sustainability and has rapidly become the largest and most widely recognized green-building design certification program in the country. The LEED program is constantly evolving and maturing and the USGBC projects the release of the next update of the LEED rating system in November 2012 (LEED 2012).
This article is the first in a series that will provide details on the current LEED rating systems and will also highlight proposed changes as they are released by the USGBC. This first article provides an overview of the existing LEED certification program, and the subsequent articles will touch on more details of each of the LEED certification program’s nine rating systems and changes proposed to those rating systems by LEED 2012.
LEED by the Numbers
Nine Rating Systems
LEED sets forth nine rating systems for reviewing projects as distinguished by specific building type, sector, and project scope. A project is reviewed under one of the following nine rating systems.
- New Construction (NC). LEED for New Construction and Major Renovations certifies (1) the design and construction of new commercial or institutional buildings and high-rise residential buildings of all sizes, public and private, and (2) extensive alteration work in addition to work on the exterior shell of the building and/or primary structural components and/or the core and peripheral mechanical, electrical, and plumbing service systems and/or site work. LEED for Schools (SCH), LEED for Retail, and LEED for Healthcare (HC) all fall under the LEED-NC rating system in certifying the design and construction of new buildings and major renovations for these specific occupancy types.
- Existing Buildings: Operations & Maintenance (EBOM). LEED for Existing Buildings: Operations & Maintenance certifies the sustainability of ongoing operations of existing commercial and institutional buildings and requires recertification at least once every five years to maintain certification status.
- Commercial Interiors (CI). LEED for Commercial Interiors certifies the design and construction of interior spaces, and only tenants who lease their space or do not occupy the entire building are eligible to seek certification. LEED for Retail also falls under this rating system in addressing tenant spaces in retail buildings.
- Core & Shell (CS). LEED for Core & Shell certifies the design and construction of projects where the developer controls the design and construction of the entire core and shell base building, but has no control over the design and construction of the tenant fit-out. Owners of LEED Core & Shell projects may require LEED-CI in tenant leases for tenant fit-outs.
- Homes. LEED for Homes certifies the design and construction of single-family and small-scale residential buildings and is designed to promote the transformation of the mainstream homebuilding industry towards more sustainable practices.
- Neighborhood Development (ND). LEED for Neighborhood Development certifies the planning and development of neighborhood projects that perform well in terms of smart growth, urbanism, and green building. For a LEED-ND project, while there is no minimum or maximum size, at least two habitable buildings has been determined to be a reasonable minimum size, and 320 acres has been determined to be a reasonable maximum size.
Seven Building Topics/Credit Categories
LEED studies seven building topics that are the same across each of the rating systems except LEED for Homes and LEED-ND. The topics consist of both prerequisites and credits. The credit categories measure the overall performance of a project by awarding points for credits achieved in each of the categories.
- Sustainable Sites (SS). In the SS category, points are awarded based on the location of the project and use of the entire project property, so as to minimize the project’s impact on the site.
- Water Efficiency (WE). In the WE category, points are awarded for water-efficient practices, both indoor and outdoor.
- Energy & Atmosphere (EA). In the EA category, points are awarded for energy efficiency, particularly in the building envelope and heating and cooling design.
- Materials & Resources (MR). In the MR category, points are awarded for efficient utilization of materials, selection of environmentally preferable materials, and minimization of waste during construction.
- Indoor Environmental Quality (IEQ). In the IEQ category, points are awarded for improvement of indoor air quality by reducing the creation of and exposure to pollutants.
- Innovation in Design (ID). In the ID category, points are awarded for special design methods, unique regional credits, measures not currently addressed in the applicable rating system, and exemplary performance levels.
- Regional Priority (RP). In the RP category, points are awarded for the achievement of credits that address geographically specific environmental priorities identified by the USGBC Regional Councils and Chapters as having additional regional environmental importance.
LEED for Homes adds the Location & Linkages topic, which awards points for the placement of homes in socially and environmentally responsible ways in relation to the larger community. LEED for Homes also adds the Awareness & Education topic, which awards points for the education of the homeowner, tenant, and/or building manager about the operation and maintenance of the green features of a LEED home. The LEED-ND rating system addresses the following additional topics: Smart Location & Linkage, Neighborhood Pattern & Design, and Green Infrastructure & Buildings.
Four Certification Levels
In order to earn LEED certification, a project must satisfy all the prerequisites and qualify for a minimum number of points to attain one of the four levels of certification. Four levels of certification are possible, depending on the number of criteria met, and indicate increasingly sustainable building practices. Certification is awarded according to the following scale for all rating systems except LEED for Homes, which follows a 136-point scale.
- Certified: 40–49 points
- Silver: 50–59 points
- Gold: 60–79 points
- Platinum: 80 points and above
Buildings that achieve one of the above certification levels will be recognized with a formal letter of certification.
The current LEED certification system in use is LEED 2009. The USGBC’s LEED 2012 update opened for public comment in November 2010. A second round of public comments opened on August 1, 2011. The USGBC staff and LEED committees review comments and recommendations and post responses on the USGBC website. Revisions of the rating system will be made based on the comments received. The USGBC membership vote on the final draft of LEED 2012 is scheduled for August 2012, with LEED 2012 set for release on November 7, 2012.