Pig, Scott., Eilers, Mark, and John Reed. “Behavioral Aspects of Lighting and Occupancy Sensors in Private Offices, ACEEE 1998 Summer Study.”
This paper examines people’s behavior as it relates to lighting usage in private offices in a university office building. Sixty-three private offices were monitored at one-minute intervals for room occupancy and lighting usage over an 11-month period in 1995. Walk-through observations were also conducted, and two written surveys were administered. Four lighting control configurations were tested; two configurations used manual dual-level switching, and two configurations used automated daylighting controls. All rooms had occupancy sensors, however these were disconnected for one group of offices to provide a control group.
The results showed that people in offices with occupancy sensors were less likely to run off the lights when they left the room. Instead they relied on the occupancy sensors to control the lights for them. They were also somewhat less likely to choose a switch setting other than full illumination from the overhead lights. Both of these findings suggest that in this kind of setting, people modify their behavior in the presence of an occupancy sensor in ways that reduce the savings potential from the device. The tendency to rely on the sensors to control the lights was estimated to reduce the savings from the occupancy sensors by about 30% in this case. Overall, the occupancy sensors were not cost effective in these individual offices from the standpoint of saving lighting energy, because people managed the lights in their offices fairly diligently. The use of blinds was also found to be a significant factor in savings from the daylight controls.