LEED is the “yardstick” by which the design and construction industry measures the sustainability of a structure, comparing multiple buildings all on the same scale in an effort to prevent green-washing. It is a nationally accepted benchmark that offers third party verification of sustainable design practices. LEED focuses on the “triple-bottom line,” taking people, profit, and planet into consideration. It continues to mature in an effort to respond to new technologies and policies, and affect market transformation. As of mid-2009, The Leadership and Environmental Design (LEED) rating system is in its third version.
There are currently nine different LEED rating systems available to choose from and select the one most applicable to your project type. LEED addresses both the design and construction phase of a building, as well as the maintenance and operations of existing structures. Within the rating systems are various credit categories including sustainable sites, water efficiency, energy and atmosphere, materials and resources, indoor environmental quality, location and linkages, regional priority, and innovation in design. There are four certification levels: certified, silver, gold, and platinum.
Changes to the LEED rating systems that appear in the new LEED version 3 guidelines, released in April of 2009, include a strong emphasis on reducing greenhouse gas emissions, addressing climate change issues, along with reducing fossil fuel and resource depletion. Indoor environmental quality has a greater focus than the previous version, as a reaction to the amount of time a typical American spends indoors, which is often over 90 percent. These areas of increased focus are demonstrated through three major differences in this newest version. There are no new credits; however, they are weighted quite differently than before. Previously in version 2.2, 69 points were available in the LEED for New Construction rating system, whereas now 100 points are available. Credits that have a greater impact on greenhouse gas emissions and climate change issues now have more points than before. Another change is that there are new prerequisites in some categories, resulting in all of the credit categories including at least one prerequisite. Previously not all of the credit categories had prerequisites, such as the water efficiency category. The third change is a focus on regional issues. Regional Priority credits are specific to a project's zip code. They are not new LEED credits, but instead are existing credits that USGBC chapters and regional councils have designated as being particularly important for their areas. The incentive to achieve the credits is in the form of a bonus point.