Striking the balance between energy saving and visual comfort in sacred structures

Across the centuries, precedent studies have showcased daylighting as the one of the key defining elements of spaces. While it does not exist in any physical forms, it possesses the ability to reveal the physical forms or recreate the atmosphere of a physical space. However, achieving the right balance in enhancing visual perception, evoking distinctive impressions and energy saving is a challenging task. This paper investigates the daylight benefits and the associated energy saving potential via studying different light treatments within a sacred environment. This study analysed the dynamic luminance contrast and luminance balance strategies adopted in a church by selective manipulation of daylight from qualitative and quantitative perspectives. The qualitative study involved surveying the occupants’ expectation and perceptions and on site monitoring. Further quantitative studies were conducted to assess the luminance and illuminance distribution and brightness contrast in the selected visual fields by using digital models. Through the comprehensive evaluation process, the benefits of the day lit and artificially lit luminous environments were compared and analysed. The energy consumption of the two lighting systems was studied and the energy saving potential of daylighting in sacred space was identified. This paper presents a holistic evaluation process which addresses both energy saving and visual comfort in the sacred realm.