Abstract: “This paper suggests a way to measure %DF using fieldwork data by taking samples in residential rooms at the University Science Malaysia. The two rooms face east and west for comparison. Two varied window to wall (WWR) and window to floor (WFR) ratios were tested for this experiment. The %DF values calculated from this research were analysed by comparing the east-facing room to the west-facing room and by comparing the different WWR and WFR. The results indicate that given the dynamic and varying sky conditions, east-facing rooms resulted in higher %DF values in both WWR and WFR. It is also found that in Malaysian skies, a 1%DF value is a good estimate for a residential room natural illumination level.”

Keywords: Daylight factor %DF, Window to wall ratio (WWR), Window to floor ratio (WFR)