The application of analytic hierarchy process in daylighting performance assessment

Daylighting is beneficial to humans and the environment. Various indicators have been proposed to evaluate its attributes. Studies on the weighting factors of these attributes are, however, sparse. This paper aims to develop a new daylighting performance assessment method by collecting the perceived importance of the attributes from occupants using the analytic hierarchy process (AHP) based on two equally important criteria - visual comfort and electric lighting energy saving potential. The study has two parts. In the first part, a general survey was conducted to verify the attributes affecting occupants' visual comfort and their acceptance of not turning on electric lights in daylit cellular offices. Brightness on desktop, brightness on surroundings, uniformity on desktop, uniformity on surroundings and perceived glare from windows were found to be the attributes. In the second part, an AHP survey was conducted to examine the weights of importance of these five attributes. The results showed that they were important to daylighting performance in the order of brightness on desktop (31%), perceived glare from windows (23%), uniformity on desktop (19%), brightness on surroundings (16%) and uniformity on surroundings (11%). The findings of this study would help to develop a comprehensive performance-based daylighting assessment method in the future.