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Liv Haselbach, guest blogger

Indoor Air Quality and Energy Efficiency Now Key to Projects Becoming Certified

The US Green Building Council (USGBC) released an updated version of its Leadership in Energy and Environmental Design (LEED) rating system for New Construction and Major Renovations in April 2009. The 2009 version replaces the 2.2 version for projects registering after the release date.

This green rating system provides a format within which buildings and their associated sites can be developed in a more sustainable manner. It requires that certain minimum standards be met for a few specific prerequisites such as nonsmoking areas and minimum ventilation requirements, and then allows the developer to choose from a list of green options for credits in several categories, each with associated point values. A certain level of points attained will allow for a project to be LEED certified, and additional points can be attained for higher levels of certification, such as the ‘silver’ level in version 2.2, with a minimum of 33 points.

Although there were not many major changes between the credits in the two recent versions (2.2 and 2009), the point values have changed significantly. The five main categories in both versions are Sustainable Sites, Water Efficiency, Energy and Atmosphere, Materials and Resources, and Indoor Environmental Quality. Overall, the relative values of the Sustainable Sites and the Water Efficiency categories from version 2.2 to 2009 have not changed much. However, the relative value of the Energy and Atmosphere category has increased by 41%, while the relative values of the total points available in the Material and Resources and the Indoor Environmental Quality categories have decreased by 32% and 35% respectively.

For specific credits, the relative value of the Energy Efficiency credit has increased by 30% while the relative value of the Increased Ventilation credit has decreased by 35%.

What this means to those designing HVAC systems is that measures that improve energy efficiency have become more important. Therefore the adoption of technologies that improve indoor air quality and simultaneously improve, rather than decrease, energy efficiency will more readily aid in obtaining LEED certification.

For more information: http://www.usgbc.org/DisplayPage.aspx?CategoryID=19

Liv Haselbach is an associate professor in Civil and Environmental Engineering at Washington State University and specializes in sustainable development.