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Skylight tube solves lighting problems

Skylight tube for efficient natural lighting

Q: Several rooms, especially my kitchen, always need the lights on. I prefer natural daylight, but I cannot afford a skylight. What do you think of less expensive skylight tube kits? Do they work and are they efficient? - Ann T.

A: As an engineer, I have been following the design, performance and feature improvements of skylight tubes over the past several years. The new models use vastly improved designs and materials that make them more efficient and easier to install. Any time that you can avoid using electric lights, you lower your utility bills and eliminate the expense of bulbs.

After researching skylight tubes over the past year and evaluating the performance claims by the many manufacturers, I finally installed a medium-size kit in my own home as the ultimate test. It is actually in my large garage where I spend time restoring cars.

The results were, in one word -WOW! The amount of light from the skylight tube kit is truly impressive. It is so bright in my garage now that, every time I leave my garage, I still reach out to switch off the light (which is seldom on). These new skylight tubes transmit light so efficiently that it glows indoors on a clear moonlit night.

Natural light makes most things look better indoors. In the kitchen, foods look more appetizing than under bulbs. Since natural light is full-spectrum light, some doctors claim that it minimizes the winter "blues." The acrylic rooftop dome and diffuser block nearly all of the furniture fading ultraviolet rays.

A bathroom or dressing area is another excellent location for a skylight tube kit. Some models now have optional ceiling vent kits to light and vent the bathroom with one unit. The trim ring around the decorative ceiling light diffuser is also an air inlet vent, which is attached to a flexible duct.

A small fan (about 150 cubic feet per minute) is mounted up in the duct. This duct branches off to the side of the skylight tube inside the attic. The fan uses a GFCI-protected circuit. Since it is located well up inside the duct near the roof, it operates quietly.

If you surf the Internet or read home magazines, it seems like everyone is selling skylight tube kits. Don't just buy the cheapest one because there are major differences in quality. The kits are shipped with various levels of preassembly for easy installation and some have lifetime warranties.

A skylight tube is simply a tube (a rigid smooth or a flexible corrugated material, 10 to 21 inches in diameter) with a super-reflective lining. It runs from your ceiling up through the roof. There is a light

James Duller is a mechanical engineer who writes on a wide variety of energy and utility topics. His column appears in a large number of daily newspapers.

Copyright 1999 James Dulley


diffuser on the ceiling and clear dome on the end that sticks up through the roof. Many of the new designs have high-quality flashings and storm collars to eliminate all leaks.

The major advantages of a skylight tube over a standard flat skylight are its low cost, simple do-it-yourself installation and energy efficiency. Since it is small in diameter and the entire tube forms a sealed dead air space, there is very little energy loss as compared to a skylight. Tubular Skylights even use a double insulated diffuser indoors for a total insulation value of R-22.

From indoors, most skylight tubes look just like an ordinary ceiling-mounted light fixture. For a more interesting and contemporary look, choose a decorative or "mood" ceiling diffuser. For example, ODL makes a changeable one with a stylish blue center cone. It can be positioned up or down. There is also a perforated cover to give a star-like appearance. The quality of the reflective tube material is the heart of any efficient skylight tube. Two of the best rigid aluminum tube materials to check for are Alcoa Everbrite 95 and 3M Silverlux. These are used by the best quality rigid skylight tube kits. Look for these names on the protective film on the reflective surface.

Rigid aluminum skylight tube sections can be rotated (45-degree angle joints) to fit around attic obstructions; however straight is preferable and most efficient. If your attic has many obstructions and you want the easiest installation method, choose a kit that uses a flexible corrugated reflective tube material. It is almost as simple to install as a flexible dryer vent duct.

If you use the area at night too, consider an optional electric light kit. A 100-watt incandescent or 20-watt compact fluorescent bulb is positioned up inside the skylight tube. This is ideal if your room does not have a ceiling light fixture and is much easier to install. If you like bright light in the early morning or evening, consider a kit with a prismatic top dome that directs more low-angle sunlight down into the tube.

Write for (or instantly download - Utility Bills Update No. 542 - buyer's guide of the best skylight tube kits, materials, warranties, sizes, features and prices. Please include $3 and a business-size SASE. Mail to: Jim Dulley, Illinois Country Living, P.O. Box 3787, Springfield, IL 62708.


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