A field study conducted by the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute boosts incentive for the use of or light-emitting diodes (LED). The study showed that colored LEDs in retail windows can cut lighting energy use by up to 50% and more readily grab shoppers' attention.

Lighting in retail stores often does more than just illuminate the space. Retailers, especially those selling high-end goods, use lighting to attract customers, highlight merchandise, and send a message about the quality of the store. Store display windows offer the greatest opportunity to attract shoppers passing by, making lighting a critical element in visual merchandising. When combined with 12 or more hours of use every day, the LRC says, the energy consumption and costs add up. Indeed, the U.S. Department of Energy estimates that lighting accounts for 37% of total energy use in U.S. retail buildings.

Building upon previous lab studies using LEDs in displays, the LRC developed an energy-efficient window lighting solution for retail stores through a study sponsored by the Los Angeles Department of Water and Power (LADWP). LRC researchers installed custom-built LED luminaires in the windows of three stores owned by a popular clothing retailer in the Los Angeles area to determine whether colored LEDs could draw the interest of shoppers, reduce lighting energy consumption in store windows, and maintain or improve retail sales. By adding colored light to the background, eliminating the general fluorescent lighting, and reducing the number and wattage of halogen accent lamps, the LRC was able to add interest to the windows with color-rather than with high light levels-and cut lighting power use by 30 to 50%.

LRC researchers tested different window display and lighting scenarios over an eight-week period and surveyed more than 700 L.A. shoppers about the attractiveness, visibility, and appropriateness of the windows. Results revealed that shoppers overwhelmingly preferred the colored window with a 30% cut in power over the typical bright-white, high-energy design. The surveys indicated that 74% of shoppers found that the new lighting design attracted their attention, and 84% agreed that the LED display windows were visually appealing. The lower levels of accent lighting on the window mannequins did not decrease the visibility of the displayed merchandise, according to 91% of shoppers.