Tubular skylight an efficient way to bring in more natural light

Posted May 24, 2024 6:00 am

James Dulley

Q: I would prefer to get more free natural light but am not sure whether to install a large rectangular skylight or a tubular one. Which one is the best choice?

A: Although the amount of electricity used for lighting in the typical house is only a fraction of that for heat, cooling and water heating, it still constitutes a significant annual cost. Using more natural lighting instead of light bulbs is not difficult to accomplish. Also, at the same brightness, most people can see much better under natural light than under artificial light.

If saving electricity is your primary concern, then replacing all your light bulbs with LEDs is the least expensive option. Although not as natural as true sunlight, the higher temperature ones, 4000 degrees Kelvin rating, produce a more natural light. Also, ones with a high CRI (color rendition index) make colors looks more realistic.

A tubular skylight is generally a more efficient and less expensive choice than a traditional rectangular skylight for natural lighting. A traditional rectangular skylight provides more lighting than a tubular one and a view of the sky. Its drawback is it creates a large hole in the insulation envelope of your roof which loses energy and it costs much more to install.

I installed a tubular skylight in my garage and it provides adequate light for most activities out there during the daytime. When there is a full moon at night, it actually produces enough light for me to walk to my car in the garage.

This is a tubular skylight being installed on a shingle roof. Notice how the shingles fit over the flashing to eliminate leaks. Courtesy of Solatube

Tubular skylights are available in several diameters depending upon how much light you need and the space available. As a reference, a small 10-inch-diameter model produces as much light as three 100-watt incandescent light bulbs. A larger 14-inch model is equivalent to using five 100-watt bulbs.

If you are still using old incandescent bulbs instead of LEDs, the annual electricity savings from installing a large tubular skylight is about $90. If you typically use compact fluorescent bulbs, or preferably LEDs, the annual savings is about $20. This might not sound like a lot per year, but the tubular skylight should last for very many years.

A tubular skylight requires no maintenance other than wiping off the clear or globe in the ceiling. The dome on the roof should stay clean from just the rain. It is not difficult to install one yourself, especially if you have an asphalt shingle roof.

Tubular skylights use a sheet metal tube which extends from above the roof to the ceiling below. The interior of the sheet metal has an extremely reflective coating so very little brightness is lost as the sunlight bounces back and forth on its way down. A clear dome seals the top of the tube above the roof and a flat diffuser snaps over the bottom in the ceiling.

In order to control the brightness, optional dimmer flappers are available to reduce light intensity. These can be operated by an electric motor (requires wiring) or a solar panel with a remote control. Another nice feature for bathrooms is a model which also works as an exhaust fan.

The following companies offer tubular skylight kits: ODL, (866) 635-4968, www.odl.com; Solatube, (888) 765-2882, www.solatube.com; Sun-Dome, (800) 596-8414, www.sun-dome.com; Tru-Lite, (520) 622-2152, www.tru-liteskylights.com; and Velux, (800) 888-3589, www.veluxusa.com.

Q: I am getting quotes on a new furnace. Some contractors are adding in a fee for the county inspectors. Is this really necessary when I am just having my old furnace replaced?

A: From a legal standpoint, the requirements for inspections depend upon your local codes. If one or more of the contractors includes it in your quote, most likely it is required by law.

I recommend paying the small fee to have it inspected. I had a new heat pump installed 10 years ago without an inspection. The contractor had dropped a screw on a wire which kept one resistance element on. It really drove up my electric bills until I found it myself.

• Send questions to James Dulley, Daily Herald, 6906 Royalgreen Drive, Cincinnati, OH 45244 or visit www.dulley.com.

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