Indoor Environmental Quality in LEED-Certified Buildings in the US

The purpose of this study was to evaluate the indoor environmental quality (IEQ) of workplaces in the LEED-certified buildings in the United States. LEED (R), standing for the Leadership in Energy and Environmental Design, is a U.S. national sustainable building benchmark as well as green building rating system adopted nationally and internationally. The study compared seven IEQ criteria in relation to occupant's satisfaction and performance between LEED-certified buildings and non-LEED-certified buildings. The seven IEQ criteria included qualities of office layout, office furnishings, thermal comfort, indoor air quality (IAQ), lighting, acoustics, and cleanliness and maintenance. The study found that LEED-certified buildings showed higher occupant satisfaction with office furnishings quality, IAQ, and cleanliness and maintenance quality than non-LEED-certified buildings. However, non-LEED-certified buildings presented higher occupant satisfaction with office layout quality, lighting quality, and acoustic quality than LEED-certified buildings. LEED-certified buildings had higher occupant performance in office furnishings quality, thermal comfort quality, IAQ, and cleanliness and maintenance quality than non-LEED-certified buildings. But non-LEED-certified buildings showed higher occupant performance in office layout quality, lighting quality, and acoustic quality. The implementations of the study include emphasis on various issues of IEQ in workplace design when complying with LEED and refinement of current LEED IEQ criteria.