Solatube

Product Summary:

Solatube, is an established manufacturer of commercial daylighting systems and tubular skylights.

Detailed Description:

Solatube, is an established manufacturer of commercial daylighting systems and tubular skylights. Tubular skylights were developed in 1989 by the Australian Steve Sutton, who founded Solatube, Inc.

Tubular skylights, or light pipes, allow daylight to be transferred from the roof to occupied space below, even when there is a considerable distance involved (such as through an attic). The system is composed of three parts: an acrylic rooftop dome and flashing, a reflective light pipe, and an interior diffuser. With most of these products, the reflective tube can bend around obstructions, or connect nonaligned roof and ceiling penetrations.

So are tubular skylights, like SolaTube, a good economic investment? Unfortunately, the payback from Solatube, at least from an economic standpoint, is not clear.

For instance, SolaTube offers a 10" tubular skylight (which costs approximately $800 to purchase and install) that produces 3,750 lumens of light during full sunlight conditions. As a 60 watt incandescent bulb produces approximately 870 lumens, this size TS can replace four 60 watt incandescent lights producing 3480 lumens total.

At 4.16 hours of use, those bulbs would use one kWh of electricity to operate or approximately two kWh per 8 hour work day. Assuming 10 cents/kWh, the four incandescent bulbs cost approximately $.20 cents/day to operate. Therefore, assuming the .20 cents per day cost and 260 work days per year, you end up with an annual cost per four incandescent bulbs of $52.00 per year. $800.00/$52.00=15.38 years to breakeven on the investment.

The bottom line is that, in most residential situations, tubular skylights, like SolaTube, cannot be justified economically based on the energy savings, though there may be other non-financial benefits.
However, it's possible that tubular skylight may make more sense in commercial buildings, which have greater daytime use. See this article.

More Information:

http://www.solatube.com