Status (updated 7/18/2007): Complete
Funding sources: CBE Industry Consortium
Project Objective
Study the performance of green and LEED-certified buildings in comparison to conventional buildings, in terms of occupant satisfaction with indoor environmental quality (IEQ).
Significance to Industry
The United States Green Building Council (USGBC) created a new framework for rating green buildings with its Leadership in Energy and Environmental Design (LEED) system. By early 2003, over 100-million square feet of buildings were undergoing the certification process through USGBC. The document has gone through three iterations and serves as a basis for a number of other rating systems, such as LEED for Existing Buildings (LEED-EB), and Commercial Interiors (LEED-CI). LEED’s environmental marketing appeal has been such that the Governor of California has mandated that all new and renovated state buildings acquire a rating of silver or higher.
With the success of the rating system, there is general agreement that LEED has brought sustainability into the mainstream of building design and construction. What is less clear is the extent to which it has actually reduced the negative effect of buildings on the environment, and/or improved indoor environments for the occupants of these buildings. Comprehensive post occupancy evaluation (POE) studies of LEED-certified buildings is needed to establish the success and shortcomings of the current LEED system, and to guide future editions.
Research Approach
We are studying occupant satisfaction with “self-assesed” green buildings and LEED-certified buildings, using CBE’s occupant IEQ survey tool and building benchmarking database. This database contains survey responses from over 200 buildings and 35,000 individual occupants, making it a useful measure for studying building performance. The survey consists of a set of core questions to assess occupant satisfaction with four main IEQ factors in the workspace—thermal comfort, lighting, air quality, and acoustics. The survey relies directly on occupants to obtain feedback about how they feel about their IEQ conditions in their space, and how it affects their effectiveness.
We compared survey results of these green and LEED-certified buildings with other buildings in CBE database. Building comparisons were done by ranking individual buildings based on their average scores in each of the four IEQ categories.
Based on the survey results, we plan to investigate the sources and influences contributing to the level of occupant satisfaction with IEQ in these buildings. We hope that this study will lead to proposed improvements to the IEQ category of future revisions of the LEED-NC rating system.
Publications
Abbaszadeh, S., L. Zagreus, D. Lehrer and C. Huizenga, 2006. Occupant Satisfaction with Indoor Environmental Quality in Green Buildings. Proceedings, Healthy Buildings 2006, Vol. III, 365-370, Lisbon, Portugal, June.
Presentations
Lehrer, D., et. al., 2006. LEED Post-Occupancy Evaluation: Taking Responsibility for the Occupants. (long version) BetterBricks USGBC Workshops, Portland and Seattle, November.
Huizenga, C., et. al., 2005. LEED Post Occupancy Evaluation: Taking Responsibility for Occupants. (short version) Greenbuild Expo and Conference 2005, Atlanta, November
