Individual dynamic lighting control in a daylit space

The objectives of the study are to observe individual preferences for dynamic lighting, individual control and possibly achieve energy savings in a daylit space. The dynamics in this study are modifications of light level and correlated colour temperature (CCT) from the electric lighting system in combination with daylight. Subjects performed office work for one day in a simulated office environment. Every 30 minutes the subjects were invited to use the dimmer controls to change the lighting conditions to their preferred level. Measurements were made of illuminance, luminance, CCT and energy use, whereas questionnaires were used to evaluate user satisfaction. The study shows that subjects tended to choose a preferred CCT level, which they maintained to some extent during the day; the subjects did not regulate according to a fixed light level throughout the day. Energy savings were not accomplished in this study and it is concluded that the field of dynamic lighting deserves more research.