Currently 1.6 million square feet of building space are being certified worldwide under LEED each day. Nearly 50,000 projects are currently participating in LEED, comprising more than 8.9 billion square feet of construction space in more than 130 countries (USGBC, 2012). In the United States and Canada, 3,700 buildings have been certified by Green Globes (Stover, 2012).
Leadership in Energy and Environmental Design
The USGBC was co-founded by David Gottfried and Michael Italiano in 1993. They invited members of environmental design, real estate, academic, governmental, and business communities to shape the development of standards to guide construction projects, to improve performance, and help design and build structures that are more environmentally sensitive and sustainable.
An initial certification program, LEED 1.0, was launched in 1998 (Smith et al., 2006). It was followed by versions 2.0 in 2000, 2.1 in 2002, and 2.2 in 2005. A system of 69 credits was incorporated in the LEED framework, and the credit structure was updated with each version. LEED 3.0, published in 2009, redistributed the points to better reflect consensus priorities about the relative importance of environmental issues. The scoring regime was modified to create a new 100-point rating system that included 4 bonus credits for sensitivity for locally or regionally important features and 6 credits for innovation in design. A new version of LEED was developed during 2012, but the USGBC has delayed its consensus ballot on LEED 2012 until June 1, 2013.
Several steps are required to earn LEED certification for new construction, major renovations, and existing buildings. The basic framework involves registration, application, submission, review, and certification. Owners or developers who seek to achieve LEED certification of a project must develop building strategies early in the process in order to satisfy a set of established prerequisites. Each of the four levels of certification (Certified, Silver, Gold, Platinum) requires satisfying a different number of earned points which are awarded as a cumulative total for each performance category in the rating. For the base level of Certified, a project must earn 40-49 points out of 100 points; Silver, 50-59 points; Gold, 60-79 points; and Platinum, 80+. Currently, there is a cost of $900 to $1,200 to register projects; the cost of certification varies by project size (USGBC, 2012).
The possible points for each of the categories for LEED-NC under version 3.0 provide a sense of how efforts for the priorities are rewarded: sustainable sites (26 points); water efficiency (10 points); energy and atmosphere (35 points); materials and resources (14 points); and indoor environmental quality (15 points). There is the potential to achieve 10 bonus points through innovative design (6 points) and regional priority (4 points) (Smith et al., 2006; USGBC, 2012).
The USGBC has also developed a set of programs tailored to different building types and different numbers of buildings. They include LEED-NC, LEED-EB (existing buildings operations and maintenance), Core and Shell Development, Commercial Interiors, Retail, Homes, Schools, Healthcare, LEED for Neighborhood Development (which may include entire neighborhoods or portions of neighborhoods), and LEED Volume certification (for organizations planning to certify at least 25 new buildings or existing buildings seeking certification of their operations and maintenance).
The LEED Volume certification program is intended to streamline the certification process for organizations that plan to certify at least 25 projects. The three-step process requires (1) registering a building prototype; (2) precertification of the prototype; and (3) ongoing certification of individual buildings as they are constructed. The program is intended to reduce costs to participants by taking advantage of uniformity in building design, construction, and operational practices and managerial uniformity within an organization in order to forgo the need for a full review of every project seeking LEED certification