Lighting quality and office work: two field simulation experiments

This paper describes two experiments concerning the effects of variations in lighting quality on office worker performance, health, and well-being. Experiment 1 had four experimental conditions: a regular array of fully direct recessed parabolic luminaires; direct/indirect luminaires with no control; direct/indirect luminaires with a switchable desk lamp; and, workstation-specific direct/indirect luminaires with control over the direct portion. Experiment 2 contrasted two conditions with no individual lighting control: a regular array of recessed prismatic lensed luminaires, and suspended direct/indirect luminaires. Participants considered the direct/indirect systems to be more comfortable than the direct-only systems, with a further increase in comfort associated with individual control in Experiment 1. There were no simple main effects of lighting quality on the performance of any task, although the expected changes in performance associated with task visibility, practice, and fatigue were found. Interactions between lighting quality and time suggested that having a degree of individual control of lighting tended to maintain motivation and vigilance over the day.