My lighting column for the February issue of tED Magazine. Reprinted with permission.

According to the U.S. Department of Energy (DOE), more than 600,000 retail buildings are currently operating in the United States, representing more than 11.3 billion sq.ft. As one of the largest markets for lighting, retail applications have distinctive needs.

“Lighting in retail spaces can be characterized in two ways—a necessary evil and a powerful tool in a merchandiser’s toolbox,” says Jay Weiland, Director, Retail Vertical, Acuity Brands Lighting. “Sure, lighting is a cost, and some retailers initially see it that way, but lighting is also necessary to help customers not only find what they are looking for, but also feel comfortable while engaging in the shopping experience.”

Customer experience is more critical than ever, Weiland adds, due to ecommerce competition. This is encouraging retailers to consider lighting not a cost but an investment in generating sales.

Lighting requirements

Retail lighting varies depending on the type of store, owner/brand goals, and merchandise being displayed. Generally, the retail market may be delineated between big box and boutique. Big-box stores typically prioritize energy efficiency, maintenance, uniformity of light levels, and low installed cost. Boutique applications typically prioritize color quality, visual comfort and setting a desired look. Both are typically concerned with using focal lighting to accent and promote key merchandise.

“Certain specialized retail applications may prioritize other unique attributes,” says Bill Foley, VP Brand Management, Cree Lighting. “For example, jewelry stores often require very small point sources with relatively high color temperatures to make gemstones sparkle while favoring lower color temperature sources for areas displaying gold.”

Weiland adds that color quality and modeling are critical in effective retail lighting. “The higher the color rendering index (CRI), the better,” he says. “A higher CRI will render colors more vividly, which is especially critical when retailing items such as clothing, produce or jewelry.”

In 2015, the Illuminating Engineering Society published TM-30, which proposes new color metrics that cover color fidelity similar to CRI but also gamut (saturation). While not standards, these metrics offer additional tools that can be used to evaluate and predict color quality.

Because shopping is primarily a heads-up visual activity, achieving good vertical light levels (typically 6 ft. above the finished floor) is often more important than horizontal light levels (typically 3 ft. above the finished floor). It’s all about the sightlines, says Sally Lee, LC, LEED-Green Assoc., Market Segment Manager-Retail, LEDVANCE (formerly OSRAM SYLVANIA). That and producing contrast to highlight key merchandise.

“Depending on store design and merchandise displays, once a general light level is established, the accent/feature display and vertical/perimeter lighting systems can be determined,” she says. “For a just noticeable difference, two to three times the general lighting is required.”

Lee adds that for accent lighting to achieve the most dramatic and visually interesting displays, a contrast of five to 10 times the ambient light level is most effective. “While all this is more easily taken care of in new construction projects, we find a lot of accent lighting in existing stores has become marginalized over the years,” she says. “It’s worthwhile to check lighting contrast to make sure the accent lighting is doing its job.”

Bloomingdale's San Francisco, California. Architects - RYA Design Consultants. Image courtesy of Acuity Brands Lighting.

Bloomingdale’s San Francisco, California. Architects – RYA Design Consultants. Image courtesy of Acuity Brands Lighting.


Foley, Lee and Weiland point to several key trends at the leading edge of retail lighting design. Notably, using lighting to create a strong customer experience, volumetric lighting, LED and control technology, and daylighting.

Customer experience. Retailers are facing fierce competition by other channels such as online. Lighting can contribute to a unique shopping experience that keeps customers coming back. “Some retailers are installing consistent lighting as an extension of their brand,” Weiland says. “Some use lighting to create multiple dynamic spaces to make their stores more of a destination. And some are starting to experiment with and use visual light communication in luminaires.”

Multimedia displays. Many stores are using multimedia displays to grab attention, enhance the customer experience, and promote key products. “We are seeing a lot of big screens in retail right now, and working them into the lighting design successfully is deliberate,” Lee says.

LED lighting. LED lighting is becoming increasingly popular in retail spaces in both new construction and upgrades. “LED lighting has become the proven path to better light for retail applications,” Foley says. “LED sources allow retailers to dramatically lower the cost of ownership through high system efficacy, long life and high color rendering.”

Lighting controls. LED technology increasingly is being paired with lighting controls to satisfy energy codes and create just the right scene. “LED lighting opens up a whole new range of opportunities for dynamic lighting control,” Foley adds. “While dimming control has long been available in various types of lighting, with LED, dimming has never been easier or more effective. LED technology also enables color tuning to a user preset or even installation-variable range of color temperatures.”

Daylighting. Some retail stores have adopted daylighting as a means of improving lighting quality, notably CRI. “And where natural light is impossible, say in the third floor of a mall, lighting technology like tunable white can get a similar emotional reaction from customers,” Weiland says. “There’s even lighting that mimics clouds passing overhead.”

Integrate or decorate. LED lighting more easily integrates into store fixtures and architecture, making the lighting disappear. Alternately, the lighting can stand out as a decorative element. “Where can’t you put LEDs?” Lee wonders. “You can even wear them. Lighting is a great tool to capture and direct consumer attention.”

Volumetric lighting. Selecting luminaires that throw light on walls and ceilings can make the retail space appear larger and more inviting. “This is a particularly important trend in big-box retail where a lack of light on the high ceilings often creates a cavelike, gloomy effect, while glare can make it difficult to see products on the top shelf,” Weiland says. “More and more highbays and striplights are becoming available with direct uplight or more vertical footcandles to create better illumination and lighting uniformity.”

Final word

“Retail customer engagement begins with an objective assessment of the customer’s environment, needs, objectives and constraints,” Foley says. “Diligence in this inquiry creates a funnel through which the variety of retail lighting solutions can be considered, eventually honing in on an appropriate solution.”

“Move quickly, Weiland advises. “Sell the total value.”