Visual comfort assessment of daylit and sunlit areas: A longitudinal field survey in classrooms in Kashan, Iran

Abstract

Visual comfort in schools enhances not only health and wellbeing, but also satisfaction and therefore learning and visual performance. This research aims at testing students’ evaluations on visual comfort through questionnaires in daylit and non-daylit areas in classrooms. Dynamic daylight metrics including Spatial Daylight Autonomy (sDA) and Annual Sunlight Exposure (ASE), codified in LEED v4, are calculated and compared to students’ evaluations. A typical high school in Kashan was selected in which subjective and field measurements were carried out simultaneously in two different oriented (south and north) classrooms during a school year (2014–2015). Simulation results show that 71% of the space in south facing classroom and 20% of the space in north facing classroom receives adequate amount of daylight while 29% of the space in south facing classroom and 0% of it in north facing classroom receives excessive amount of sunlight. According to simulations, each classroom has been divided into daylit and sunlit areas, in which students’ assessments about daylight and sunlight have been separately analyzed based on their position. Comparing simulation and survey results show that while students’ evaluation about daylight availability in daylit areas is mostly positive, daylight uniformity is not considered “enough” in these areas. Moreover, students’ impression about daylight availability in non-daylit areas is rather neutral and more optimistic than simulation results. More interestingly, most students in both sunlit and non-sunlit areas of classrooms do not feel much direct sunlight and glare. In fact, questionnaires’ results show a wider range of sunlight acceptance in south facing classroom and visual comfort in north facing classroom than simulation results. According to the results non-daylit areas or sun-lit areas defined by dynamic metrics would not necessarily cause visual discomfort, suggesting that some other factors (e.g., view, configurations of windows, expectations and region) can change the degree of comfort experienced in each space.