Window area and room sizes for daylight and energy efficiency: literature versus computer simulation

Abstract

Windows may be responsible for a major part of heat gains or losses in a building. If not carefully considered, windows may often contribute to a high energy consumption in a building. Large window areas may provide good daylight provision and a good view, but they also allow for correspondingly large heat gains or losses that will affect the energy consumption of the building. This paper compares results obtained from computer simulation by using the VisualDOE programme with information obtained in the literature about window area for view and also about room dimensions to allow for a better daylight provision. It is concluded that window areas recommended for view tends to be larger than those recommended for energy efficiency and are therefore not adequate. This implies that by specifying a minimum window area for view rather than a window area to optimise the energy efficiency of the building, might incur a higher energy consumption. It was also verified that shallow rooms, as recommended in the literature for better daylight provision, are not appropriate to allow for low energy consumption.