Prediction of Discomfort Glares from Windows: Influence of the Subjective Evaluation of Window Views

Lighting in buildings can exert a large influence on the comfort, well-being, and health of occupants. A window plays a major role in providing both natural lighting in buildings and a view out, so that occupants can keep in touch with the external environment. Thus, it is essential to understand what the visual requirements are to meet occupants' needs and how window views could affect those requirements. This study aims to reveal occupant perception on window views and to identify its effects on the assessment of glare from windows. This paper presents the results from the experiment conducted in a chamber with a simulated window, which can render various window views and luminance conditions. Forty-eight subjects participated in the experiment. The results show the evidence that the glare sensation of occupants could vary with the occupant's perception on window views under the same luminous conditions. A discomfort glare index that predicts a subjective discomfort glare as a function of background and window luminances, position index, and perception on window views, has been developed by this study. A comparison between the developed and existing glare prediction models was discussed in this paper.