Windows and Offices: A Study of Office Worker Performance and the Indoor Environment


Heschong Mahone Group, Inc., October 2003

Review by Scott Schuetter, Energy Center of Wisconsin: 

The Heschong Mahone Group, supported by the California Energy Commission, conducted two field studies to determine the impact of the daylight and windows on office worker productivity. Both studies were of office workers at the Sacramento Municipal Utility District call center.

The first study tracked 100 workers' average handling time of calls over two timeframes; a 4 week period and a 3 week period. Linear regression was then applied to understand the impact of a wide range of environmental and work-related variables on the handling time. The study found that workers with a view of a large window tended to have decreased times than their counterparts with no view. The study also found that the absolute level of light, whether from daylight or an electric source, had no significant effect. Similarly, the effect of partition height was small.

The second study tracked the performance of 201 workers on five different cognitive tests. The tests measured visual capabilities as well as short and long term memory and were given at the same time on the same day of 5 successive weeks in the fall. Having a view again increased performance, while those workers with a view reported less fatigue and overall better health. It was also reported that the quality of the view, such as having sky and trees, was important. Alternatively, those workers experiencing glare tended to have decreased performance. However, the impact of both of these variables was small.

The report emphasizes that daylight can have both a positive or negative effect on worker productivity, depending on the way in which it is introduced. Daylighting designs with even illuminance distributions, quality views with no distractions, and minimal glare and heat gain had positive impacts on performance. Daylighting designs that introduce glare or thermal discomfort had a negative impact on performance.