As the days shorten and nights grow longer, many of us are milking daylight hours for all we can. Squeeze more daylight out of shorter days using an old idea — skylights — and bringing it up to date with new technology: light tubes, also known as solar tubes. Such a green home improvement project illuminates interiors with natural light, helping you fight Seasonal Affectedness Disorder and brighten your mood, as well as saving energy in rooms where you would be using electric lights during the day.

Traditionally, skylights have been the choice for homeowners adding extra sunlight into interiors. These roof windows let in abundant light, but that direct light can fade upholstery over time and allow heating or cooling to escape, raising energy bills. Skylights have also been known to gather condensation that can drip into rooms.

Light tubes, which are becoming more popular in green building plans, have an edge over traditional skylights for a handful of reasons.

“Solar tubes concentrate light through the dome and actually bring in more light overall than a traditional window-style skylight,” says Norm Delle of Galaxy Daylighting in Alexandria, Va. When installed into a window-less bathroom, “there’s no need for vanity lighting during the day,” Delle says.

Most solar lights are installed to illuminate bathrooms, though they can be built into any room. And, unlike a skylight, light tubes can be directed through an attic or room not directly under a roof.

Light tubes generally have more flexibility when it comes to location — you can put them in where you can’t put a regular skylight, because there’s an attic or other obstruction, explains Chris Beyer of Skylight Guys in Phoenix, Ariz. In fact, light tubes are a quicker and less expensive alternative to traditional skylights: While regular window-style skylights can take two days to install and drywall, light tubes can be installed within hours for a cost ranging anywhere from $375 to $700, with installation.

“Plus, light tubes are more energy efficient,” Beyer says. “They don’t let heat in or out.”

Solar tube lights have a roof-mounted unit, typically a clear dome that captures sunlight. Full-spectrum sunlight travels down shiny metal tubing — typically lined with highly reflective liquid silver that’s chemically bonded to the aluminum. Down the tube (which ranges from 10 inches to over 20 inches in diameter), sunlight hits a frosted glass diffuser and illuminates a room with bright, indirect light. UV filters can save interior fabrics from fading.

Short and straight light tubes work best, but tubes can be curved around rafters and between walls to reach dark spaces. During a full moon, light tubes can even pick up silvery moonlight.

Like more control over your day lighting? Some light tubes have a dimmer control so you can adjust light intensity.

There are even hybrids that let in natural light by day and switch to fluorescent when the sun goes down, such as the models that bear incandescent bulbs or compact fluorescent bulbs.

Even more high-tech are light tubes with solar florescent capability that can capture UV rays as florescent polymers, convert them into red and green light, and illuminate interiors on overcast days.

Another high-tech light tube version has fiber optics in the tube instead of reflective material. A series of lenses absorb light on the roof, then light is channeled down fiber optic lines plunging two stories down. These cables can even have UV-filtering barriers that screen out harmful rays.

Fiber optic tubes and solar-storing fluorescent tubes are still much too expensive for the average homeowner, costing more than double a regular solar tube, and aren’t yet ready for the market yet. “They’re still pretty inefficient,” says Beyer.

For now, green homeowners hoping to add some efficient lighting will do well to see where a light tube can let some sunlight in.

Photos: Courtesy Solatube.

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Solar tubes help milk daylight
Solar light tubes, which are becoming more popular in green building plans, have an edge over traditional skylights for a handful of reasons.