Prior to this study the relationship between daylighted buildings and occupant productivity had not been rigorously documented. These results indicate a clear direction for building design and use. Daylight design, when done with care, also reduces energy by 30-60% in commercial and institutional buildings. With the addition of full spectrum light, a dynamic improvement in productivity, sales, and health may be achieved.

Retail sales analysis included data from 108 stores, two thirds with skylighting. The study found that skylights [or natural daylighting from full spectrum fluorescent tubes] significantly correlate to higher sales with 99% statistical certainty. According to the study, a skylit store would be likely to have an average of 40% higher sales than similar stores without skylights, with an expected range of increase between 31-49%. Thus, if a typical non-skylit store were averaging sales of $2/sf, an increase in sales to $2.61-$2.98/sf could be expected.

Duro-Test Vita-Lite simulates natural daylight.