IMPACT OF WINDOW-TO-WALL RATIO, GLASS REFLECTANCE, AND SURFACE REFLECTANCE ON INDOOR ILLUMINANCE: A SIMULATION STUDY USING DIALUX

The growing adoption of window facades in buildings has enhanced the use of daylighting, which has generally been well-received by occupants. However, the effectiveness of daylighting in interior spaces can be influenced by several factors, including the window-to-wall ratio (WWR), glass visible transmittance (VT), and the reflectance of walls, ceilings, and floors. This study investigates how these factors affect indoor average illuminance. To model the indoor lighting environment and adjust these factors, a simulation method using DIALux software was employed. Multiple linear regression analysis was then used to assess the impact of each factor on average illuminance. The results reveal that WWR and VT are the most significant variables, with their increases leading to substantial improvements in illuminance, though the benefits diminish at higher levels. In contrast, ceiling and floor reflectance have minimal effects, with ceiling reflectance being the least impactful. The regression analysis validates the model's high predictive accuracy and highlights the critical role of WWR and VT in achieving optimal lighting conditions.