Subjective experiments on the suitable illuminance in a living room daylitby Mirror Duct System

The objective of this study is to identify theeffects of mirror duct system on energy savingsfor luminaries. The results of the experimentsshowed that more than half of the subjects judgedthe room was bright when the illuminance on thedesk from mirror duct system was higher than100 lx. Half of the subjects judged ceilinglurninaire could be turned off when theilluminance on the desk was higher than 100 Ix inthe case of relaxing. On the other hand, about80% of the subjects always switched on theluminaire regardless of the illuminance on thedesk in the case of reading.