Optimal office lighting use: a Swedish case study

The purpose of this paper is to determine the optimal office lighting use with different types of lighting controls to achieve energy savings and provide visual comfort for individuals.

A case study and field measurements were carried out in 18 single-occupancy offices in Sweden where six different lighting controls were investigated. Occupancy and daylight hours were key issues for determining the lighting use. For each office, occupancy patterns, use of a ceiling luminaire, energy usage and perceptions of office lighting in the spring-summer and autumn-winter were established.

The use of luminaires varied among the occupants and could be habitual. Though the study yielded positive results concerning the potential for manual or daylight dimming with occupancy switch-off controls to increase optimal lighting use, combining dimming controls with manual on/off controls is rather effective if occupants generally sit in their offices most of the day.

Precise comparisons of the performances of the different controls were limited due to the offices’ different window orientations; thus, measurements in identical offices are desirable. The small sample size limited analyses of lighting use and the personal perceptions of lighting quality.

Apart from the contribution to simulation techniques, the findings imply that office lighting controls should be selected taking individuals’ behavioural patterns and perceived lighting quality into consideration.

This paper describes an approach to determine the use of lighting controls and provides a basis for establishing optimal lighting use for individuals with regard to occupancy and daylight availability.