Future of commercial skylight market looks up
Sunlight represents sustainability and other benefits of replacing noxious fossil fuel byproducts.
As pressure to save energy mounts, green architecture and building movement drive increased use of daylighting, and the future of skylights looks bright, says John McHugh, lead technical engineer, Heschong Mahone Group Inc., Fair Oaks, Calif. Evolving building energy codes, such as the California Title 24 standard, are expected to favor, or even mandate, the use of skylights in large flat-roof commercial buildings. Skylights can lower electric lighting bills by one-third or more, industry experts say.
The United States Green Building Council’s green rating system, Leadership in Energy and Environmental Design, rewards building owners with coveted points for daylighting with skylights. That said, manufactured residential and light commercial skylight sales in the United States have been flat of late. According to the 2005 AMMA/WDMA U.S. Industry Market Size Report, conducted by Ducker Research Company, Troy, Mich., the total skylight market declined by 6 percent in 2005, compared with units manufactured in 2000. Of the reported 1.5 million residential-type skylights made in 2005, about 270,000 were used in light commercial applications including small office and retail buildings. The study does not include non-unit sloped glazing or custom architectural applications or a report on the growing repair and replacement market.
Types, kinds and sorts
The skylight industry is divided into residential and commercial sectors, or peaked roof and flat roof. It also can be divided into functional and architectural categories, from mass-produced, square roof windows to the highly customized atrium and sloped-roof skylights in monumental buildings.
Tubular skylights that yield diffused daylight without a view of the sky, are used in both residential and commercial situations. These skylights will become more common in commercial buildings, predicts Stephen Selkowitz, head, Building Technologies Department, Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Calif. “Light pipes eliminate the need to build a light well,” he says. “They’re already popular in warehouses and retailers, and we’re starting to see them in offices.”
A light pipe makes sense where the roof structure is significantly above the ceiling, and the light needs to be transmitted efficiently between the roof and the ceiling, Selkowitz says. Conventional skylights, on the other hand, are better in an area where a large open space has to be daylit. “Skylights can make an architectural statement, where light pipes are strictly functional,” he says.
Mechanical louvers are showing up on sloped glass as well as on vertical glass in large commercial buildings. Light controls orchestrate electric lightingby opening louvers or raising screens automatically as the sun shifts through the day. Super Sky Products Inc., Mequon, Wis., installed such a system on the new New York Times Building.
The company uses aerogel, the lightest-weight solid in the world, for diffused lighting. It has a content of 5 percent solid and 95 percent air. The silica product has small pores to combine thermal protection with diffused light and sound reduction. Super Sky officials infuse it between polycarbonate panels framed in U-channel for a super-insulating sandwich and diffused daylight. Cabot Corp. of Boston produces Nanogel, its family of silica aerogels.
Electrochromic coatings on glass, sometimes known as “switchable glazing,” is expected to improve building occupants’ comfort and productivity when used on skylights and vertical glass in concert with daylighting controls. Sage Electrochromics Inc., Faribault, Minn., is a leading developer of electronically tintable window technology. Velux Skylights, Greenwood, S.C., is offering it as a pricy new option that eliminates the need for mechanical window coverings, says Andrew Blick, Velux commercial product manager. The company also makes light-controlled venting units powered by the sun, he says. Ten percent of all commercial skylights are operating units, he estimates. Other advanced glazing systems control solar heat gain, ultraviolet fading of furnishings and thermal loss.
Integrated photovoltaic skylights combine solar electric panels and daylighting in systems that enhance the architectural character of some projects by Super Sky. (See sidebar, right.)
Codes, LEED favor skylights
“The green building movement is fundamentally changing everything,” Selkowitz says. “Skylights are benefiting from the United States Green Building Council’s LEED certification and by the desire for more daylighting.”
One of the biggest barriers to commercial skylight use will be removed when state building energy codes require them, McHugh says. “I’m the author of California Title 24 building energy efficiency standard, the greenest standard in the U.S.,” he says “The standard states that low-rise flat-roof buildings greater than 25,000 square feet in area, and with ceiling heights greater than 15 feet, are required to have skylights.”
Selkowitz and McHugh say a new 2008 California standard might mandate skylights in buildings of 8,000 square feet or larger.
“The smaller the space, the farther apart you have to space the skylights,” McHugh says. “Larger skylights are cheaper than using multiple smaller skylights in the same space. As the ceiling heights drop, you need more skylights. The higher the ceiling, the fewer skylights you need to light the same space.” The cost of the light well more than doubles the installed cost of the skylight, he says. The added cost of multiple light wells can discourage skylight installation in low-ceiling applications, he adds.
“The green building movement, as well as the rising cost of traditional energy sources, is driving skylighting sales,” says Rod Kivilioja, sales manager for Super Sky Products. “Skylights will continue to be a good business, and the role of glass fabricators is also secure as glazing system requirements become more and more sophisticated.” Kivilioja notes other skylight trends worth watching. “Building designs involving skylights have become more and more complex,” he says. This trend favors companies that specialize in the large architectural side of business requiring custom skylights, as opposed to stock sizes and shapes. Often the entrances of important buildings built today feature atriums incorporating skylights and vertical glass to bring more daylight into the entry area.
The skylight repair business is growing since a lot of 30-to-50-year-old units are in need of replacement, Kivilioja says. “After 20 years, you typically start to see seal failure in skylights, especially on sloped glass installations,” he says. “We are benefiting from re-glazing as needed, as well as the need to totally replace old systems that don’t meet the requirements of today’s building codes. Replacement now represents about 10 percent of our business.”
Modular skylight wells should offer new hope of controlling the cost of installed skylights in buildings with slanted ceilings because they are factory-built and uniform, and therefore easier to work with than custom light wells that cost more and take more time to build, McHugh says. “Right now, skylights are primarily used in big box and warehouse applications with flat roofs,” he says. “But modular light wells can open up the market to include buildings with slanted ceilings, which represent approximately 60 percent of commercial building space.”