Daylighting and Retail, PART III of III

Recent studies report that daylighting can offer retail establishments a strong competitive advantage. This is supported by a study commissioned by PG&E that compares the retail sales performance of 108 stores operated by a large (unidentified) chain retailer. Two-thirds of the stores had skylighting, and the remaining one-third did not. Otherwise, the stores were very similar, with the same basic interior design, the same merchandise and all management and advertising handled by headquarters. Considering several factors, skylighting was found to have the largest impact, boosting a store’s sales index by an average of 40 percent.

The appearance of daylighting very often contributed to achieving a fresh appearance: clean, crisp, clear and bright. One effective application of daylight is incorporating skylights in the changing room to provide an opportunity for consumers to see natural skin tones, and fabric colors as they will be experienced outside of the store.

Wal-Mart Success Story


Many Wal-Mart stores and distribution centers around the world include a daylight harvesting system, which integrates skylights that dim or turn off interior electric lighting in response to the amount of daylight available. By using dimmable T-8 fluorescent lamps, electronic continuous dimming ballasts and computer controlled daylight sensors with approximately one skylight per every 1,000 square feet, they take full advantage of natural light when available.

Daylight harvesting is estimated to save up to 75 percent of the electric lighting energy used in the sales area of a supercenter during daylight hours. Each daylight harvesting system is estimated to save an average of 800,000 kWh per year, which is enough energy to power 73 single-family homes (11,020 kWh average annual usage) for an entire year.

Every facility Wal-Mart builds today from the ground up includes a skylight/dimming system. Nationwide, Wal-Mart builds or converts 200-300 facilities each year. All new stores will include the daylighting system.