How can software technology support recent updates to the LEED rating system? On April 27, 2009, the USGBC launched the much-anticipated update of the organization’s LEED sustainable design rating system, LEED Version 3 with revisions to the rating system itself (designated LEED 2009), a system update to the online certification system LEED Online, and a new certification process to be administered by a newly created organization, the Green Building Certification Institute.[1]

The approach to assessing levels of sustainability in LEED 2009 is very similar to that of previous versions of the rating system. The enhancements offered by the new system include harmonization of credits to improve consistency of application across different LEED variations, credit weightings to increase focus on energy and emissions, and regionalization which gives local areas an ability to incent the adoption of specific strategies. LEED 2009 places greater emphasis on understanding whole building energy requirements.

Informed decisions early in the design process are critical to achieving the highest levels of efficiency -- a significant goal of LEED 2009. Sustainable design and analysis software technology provides opportunities for owners, designers, engineers and contractors to support the new credit weighting emphases on increased energy efficiency and carbon dioxide emissions reductions. The process of design and construction based on building information modeling (BIM) process links models to analysis tools that predict energy consumption.

Increased energy efficiency

Building performance analysis software tools accept data from models and predict the energy efficiency that proposed designs will achieve. These tools evaluate heating and cooling requirements, identify daylight­ing opportunities, and assess building equipment selections to reduce energy use. Local weather and electric grid data are used to estimate building energy consumption and carbon emissions.

Energy reduction efforts yield cost savings and meet regulatory requirements for energy reduction. Building information models yield insight about sustainable design and meet the imperative for reduced greenhouse gas emissions and reduced energy consumption.

Carbon emissions reduction

Some tools accept model data and conduct carbon emission analysis to compare emissions implications of specific design alternatives and to better understand the potential for renewable energy application[2]. Powerful Web-based whole-building analysis tools are also available through BIM software technology[3].

BIM supports developers and building owners who need to meet LEED requirements to predict the energy performance of proposed renovations and retrofits by enabling users to:

• Create models for existing buildings;
• Conduct energy-analysis studies;
• Propose alternatives;
• Analyze and compare building performance for these alternatives; and
• Perform retrofits aimed at energy improvements.

The LEED 2009 focus on energy and emissions calls for more rigorous design practices and the development of consensus among owner, design and construction teams. BIM analysis and visualization tools increase the clarity of presenting sustainable design ideas to the project team, stakeholders and decision makers improving the process of consensus-building and providing valuable insight to support design decision-making.


References:

[1] www.usgbc.org/DisplayPage.aspx?CMSPageID=1970
[2] Autodesk Ecotect Analysis
[3] Autodesk Green Building Studio web-based technology, available through subscription to Ecotect Analysis