Daylight and Productivity

Friday, December 4th, 2009

The relationship between daylighted buildings and occupant productivity had not been rigorously documented prior to this study done in 1999 for Pacific Gas and Electric. The Daylighting and Productivity Study examined the correlation between occupant productivity and exposure to daylight within retail and school buildings. The study demonstrates increased sales (average 40% with 99% statistical certainty) and better school test performance (typically 10-20%) when occupants are exposed to daylight. This indicates a clear direction for our future building investments. Daylight design, when done with care, is the single most powerful strategy to reduce energy use in commercial and institutional buildings (from 30-60% reduction). Daylight has now been shown to increase productivity as well. The combined assets of daylighted buildings will help to remove market barriers to using daylight in commercial and institutional building design.

“Retail sales analysis included data from 108 stores, two thirds with skylighting. The study found that skylights significantly correlate to higher sales, with 99% statistical certainty. 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 with the addition of a skylighting system.”

California Board for Energy Efficiency Condensed Report
Skylighting and Retail Sales
August 20, 1999