Evaluation of the effect of daylight on room brightness

Abstract

The purpose of present study is to investigate effects of daylight on room brightness using a reference matching method. Participants observed two scale models simulating a room. One was a test room with a window through which artificial daylight entered and the other was a reference room without a window. Participants made brightness match by adjusting illuminance of the reference room with various illuminance levels (from ceiling luminaires) of the test room and window sizes. The results showed that, at the illuminance levels below 300 lx, the illuminance adjusted by participants was low even if the daylight increased the total illumiance of the test room. However, the adjusted illuminance increased efficiently with the daylight at the 1000 lx illuminance level. These results suggest that effects of daylight on brightness change with illumiance levels. The results were also discussed in terms of those of previous study using a magnitude estimation method.