Wal-Mart, the world's largest retailer, first tried out its bright idea -- skylights -- at a store in Oklahoma. The "early experiment" was in 1995, when the roof of a new Wal-Mart Supercenter in Moore was dotted with skylights.
Wal-Mart, the world's largest retailer, first tried out its bright idea -- skylights -- at a store in Oklahoma.
The "early experiment" was in 1995, when the roof of a new Wal-Mart Supercenter in Moore was dotted with skylights. At the same time, skylights were being added to a roof at a Wal-Mart in City of Industry, Calif., said Charles Zimmerman, Wal-Mart's vice president of prototype and new format development.
The skylights worked, paying dividends in natural light and lower energy costs.
Almost every Wal-Mart built since then -- more than 2,000 Wal-Marts, Supercenters and Sam's Clubs stores -- has been constructed with skylights, Zimmerman said.
The skylights are connected to fluorescent lights, which automatically dim or turn off as the natural light becomes brighter.
In all, it costs more than $200,000 for a store to be outfitted with skylights during the construction stage, including the electronic dimming ballasts and computer controlled daylight sensors. "In less than two years, the energy savings will pay for those different costs all rolled together," Zimmerman said.
The mammoth Edmond Supercenter, which spreads out over 212,000 square feet, is outfitted with 180 skylights, letting in streams of sunlight every 50 feet.
"It's a huge difference. It's like night and day, literally," manager Mike Davis said.
Davis' previous store was built in 1981 -- without skylights.
"It was dark, almost claustrophobic," he said.
The Supercenter on Interstate 35 opened in September. Natural light has enhanced the shopping experience. "It makes the customers feel more welcome. It makes the associates feel better about work. That's always important," Davis said.
Studies have shown employees are more productive working in natural light. What the Wal-Mart knows for sure is that the skylights save money in energy bills, Zimmerman said.
Wal-Mart's official stance is "we truly believe that corporations can develop and implement practices that are good for the environment and good for business."
Since 1995, Wal-Mart estimates its "daylight harvesting system" has saved annually about 600 million kilowatt-hours -- enough power to supply about 53,390 homes per year.
To learn more about environmental sustainability, Wal-Mart has built an experimental store in McKinney, Texas. Energy used to light a typical Supercenter is about 1.5 million kilowatt-hour per year. Savings in McKinney are projected to approach 300,000 kwh a year. Skylights attached to lighting systems have been used in commercial buildings on both coasts, as well as in Europe, said architect Jay Yowell, whose area of interest is sustainable design. "It's not as revolutionary as it was five years ago."
Companies install the energy-efficiency skylights because it pays off in lower energy costs.
"It all comes down to the dollar. They are not doing it because they love trees or the spotted owls."
Despite the possible benefits, Yowell said, he didn't know of any public buildings -- other than Wal-Mart -- using energy-efficient skylights in Oklahoma.
While it's usually not practical to add a skylight to a building after it has been built, it is simple to save on lighting energy costs by switching to compact fluorescent light bulbs, Yowell said.
CFL bulbs that have been approved by the federal Energy Star program use two-thirds less energy than standard incandescent bulbs while providing the same amount of light. The CFL bulbs last 10 times longer and save $30 or more in energy costs during the lifetime of the bulb.
If every American home replaced one light bulb with an Energy Star light bulb, enough energy would be saved to light more than 2.5 million homes for a year and prevent greenhouse gases equivalent to the emissions of nearly 800,000 cars, according to the energy star program.
Yowell said he is converting his own home to CFL bulbs, partly because the cost had dropped. "It used to be that one bulb was equivalent to a whole case of light bulbs. It's not such a shock now."
In addition, Yowell said, the CFL bulbs are available at stores everywhere, including the new Wal-Mart in Edmond.
Copyright © 2006, The Daily Oklahoman
Source: Knight Ridder/Tribune Business News
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