Daylighting Impacts on Retail Sales Performance

This paper reports on a study of the effect of daylighting on sales performance. In this project, we established a statistically compelling connection between sky-lighting and retail sales. The methodology used to conductthis research is described and the results are presented and interpreted. For the retail study, average sales for 108 stores of a retail chain were compared, controlling for age and size of store, hours of operation and location. The stores were very similar with the same products, the same approach to merchandising and the same management. Two thirds of the stores were equipped with skylighs that provided general illumination, and which included automatic photosensor controls to reduce electric lighting when there was sufficient daylighting. The remaining third of the stores had conventional electric lighting with no skylights. The findings of this study show significantly higher retail sales in the stores with skylights, and they suggest that there is an important relationship between daylight availability in buildings and human factors that affect sales performance. Possible causal mechanisms are discussed, along with limitations of current findings and future research directions. The paper also presents an important methodology that may be applicable to other areas of lighting research.