User interaction for personalized total light management

Despite the potential energy savings of automatic lighting control in office buildings, findings show disappointing performance due to poor usability. To explore solutions with a potential to improve user satisfaction with these systems, an iterative user-centered design was done to propose personalized system behavior and an easy-to-use user interface (UI) for total light management (TLM). The steps included defining the semi-automatic system behavior that implicitly derives user lighting preferences from user interaction with the system. Four control options were evaluated in an expert review. Based on the received feedback a redesigned UI was subsequently evaluated as part of the TLM system in a Wizard-of-Oz study. The results showed that the UI offering direct control of lighting dimming level and the position of the blinds offered higher level of usability than the UI with indirect control in which a user defines the desired illuminance from a combination of artificial lighting and daylight.