Impact of Window Size and Sunlight Penetration on Office Workers' Mood and Satisfaction

Sunlighting or direct-gain passive solar strategies let sunlight penetrate the living space. In environments where the well-being of the building occupant is a salient concern to the designer, this intrusion of sunlight ought to be controlled so that it does not impede the performance of the occupant. This study investigates the impact of window size and different amounts of sunlight penetration on occupant emotional response and degree of satisfaction. Unlike previous sunlight requirement studies, sunlight penetration is measured not in terms of duration, but rather in terms of size of sunlit areas, and therefore as a visual stimulus. The study was performed in an office room of a typical size. It was found that window size did not significantly affect the occupant emotional state or the degree of satisfaction. Sunlight penetration significantly affected the feeling of relaxation when the observer was sitting sideways to the window and the relationship had an inverted U-shape. The study stresses the validity of this novel way of assessing sunlight penetration in terms of size of the sun patches inside the room and its importance as a significant environmental attribute and design parameter that ought to be accounted for during the design of windows in sunlighting or direct-gain passive solar strategies.