Solatube brings daylight indoors

The Vista, Calif.-based company earlier this week detailed an update to its "daylighting system." The system consists of a plastic dome that sits on a building's roof and a reflective tube that carries the light inside.

But this is more than just a fancy name for a skylight.

The dome of Solatube's daylighting system is actually a Fresnel lens shaped to maximize light intake while cutting out ultraviolet and infrared light. The tube that transports light is made of reflective material and can be bent to carry light to under-lit rooms.

Having abundant light inside a building can certainly brighten up a person's home. But commercial and municipal clients are increasingly seeking out daylighting systems as well. Such investments in natural lighting are often justified on the basis of higher worker productivity, decreased absenteeism, or better retail sales.

"Daylighting is huge," said Kenneth Weston, an architect at Oak Point Associates who is certified to work on so-called green buildings. "We sell it on those facts and figures (around productivity), but mostly people just want access to daylight. On a subconscious level, when you're designing someone's work space, they always want the office by the window versus the cube in the middle."

Indeed, Solatude may sell primarily to homeowners and residential architects right now, but a bigger opportunity lies in selling to businesses, said Neall Digert, vice president for commercial market development at Solatube.

"Commercially we are applying this to literally all building types, from schools, warehouses, office spaces or stores," he said.

Other daylighting companies also have built roof-mounted fixtures to carry in light. Both Nature's Lighting and Sunlight Direct, which was spun out of the Oak Ridge National Laboratories last year, focus on the commercial market.

Light controls
The latest system from Solatube has a number of enhancements designed to provide even light and reduce the amount of heat loss or gain.

The product was first conceived in the 1980s in Australia as an improvement over skylights, which are used more often to bring light in.

The new dome has a molded lens to capture light at low angles, which means it can operate better earlier and later in the day. The flashing that sits on the roof avoids the use of caulking to prevent leaks and moisture, a common complaint with skylights.

The dome and the tube that carries the light inside the building are made of a reflective acrylic that manages to maintain almost all of the light regardless of the distance it travels, Digert said. And enhancements to the lens and a dimmer allow the fixture to have a more consistent light over the course of the day, he added.

"We've been able to engineer out the shifting patterns of light you'd associate with a skylight," he said. "Because of our optics, we can control very precisely how to diffuse light into the space."

Depending on the model, the daylighting system can illuminate 200 feet or 300 feet. The lens also can reduce the amount of heat lost through the dome and maintain the color of natural light.

Weston at Oak Ridge Associates said that although there is a rising interest in architecting daylight into buildings, often commercial or municipal clients shy away from skylights because of fears about leaking. That said, flashing and sealants have greatly improved, so a properly installed system shouldn't have problems, he said.

His firm has not used roof-mounted systems, instead favoring large windows or "light shelves" that bounce light off ceilings as a way of maximizing daylight.

"The big issue with natural light or daylighting is controlling glare," he said. "Productivity goes down in the presence of glare."