According to Heschong Mahone Group, daylight is as important in predicting an increase in retail sales as factors such as parking, number of competitors, and demographics. The same group also found that call center workers experienced the following performance improvements with increased daylight:

13%	increase in productivity from natural daylight
12%	increase in processing speed with window view
25%	improvements on mental function tests with view
17%	improvement on mental function tests with natural ventilation

Green Design Resources:

• Windows and Offices: A Study of Office Worker Performance and the Indoor Environment (PDF)
• Effect of Indoor Environmental Quality on Occupant's Perception of Performance (PDF)
• Metropolis Magazine: Green Office Buildings and Green Leases
• Promote Health and Well-Being
• CNN: The Business of Green