Technology Snapshot & Benefits:
Solar tubes are tubes that run from the ceiling of a room to the roof, where they collect light that is reflected down the tube and then diffused into the attached room. Solar tubes work like skylights but are less expensive, require less roof/ceiling space, and can be easily installed in almost all buildings. They can even work in the basement or the first floor of a two-story house if there is a closet, a chase, or any place to feed through the solar tube up to the roof. Solar tubes are made to look like ordinary ceiling lights and can easily blend into a home. They are carefully built to maximize the amount of light provided, and can light 100 to 600 square feet of space, depending on the depth and diameter of the tube. Short, wide solar tubes provide the most light. A 10-inch solar tube can produce 3,750 lumens of light, whereas a 60-watt incandescent bulb only produces 870 lumens. This means that one 10-inch solar tube can replace about four 60-watt incandescent bulbs! Solar tubes also produce roughly 68 percent less heat than the average light bulb.

Solar tubes require no electricity to run and produce no pollution. This can result in energy cost savings and contribute to a healthier planet. The natural light that solar tubes provide also has been shown to have numerous benefits for the people living in the home. According to the National Health and Environmental Effects Research Laboratory of the EPA, natural lighting can contribute to psychological and physical health by boosting energy and concentration levels. A study by the Florida Energy Conservation Assistance Program showed that natural lighting resulted in reduced eye fatigue and headaches by providing better light and matching the normal functional rhythms of the human body. Having access to natural light also helps the body produce vitamin D.

Solar tubes are also commonly referred to as tubular skylights or sun tubes. The leading providers of solar tubes are SolaTube and Velux.

Estimated Cost Savings:
Because solar tubes require no electricity to run, replacing lights with solar tubes will reduce monthly energy bills. The savings depends on the type of light bulbs the solar tubes are replacing (incandescent or CFL), the amount of time the electric lights were normally left on, and the number of electric lights replaced with solar tubes. Solatube, a leading manufacturer of solar tubes, reported that they saw an 86.1 percent reduction in daytime lighting costs and a 68.2 percent reduction in nighttime lighting costs when their headquarters incorporated 21-inch solar tubes. This is a very high number and, again, the reduction percentage depends on the amount of lights replaced, size of the solar tubes, and initial costs.

Installation of solar tubes usually costs between $500 and $800, depending on the size of the tube and the features installed (see "Issues" for more information on possible features). It also costs more if tube extensions are required to install the solar tube. This is less expensive than typical installation costs for regular skylights. Installation costs should be weighed against long-term savings for each particular case. Some investments will pay for themselves more quickly than others; in some cases, you might even be able to make a small profit by installing solar tubes. It is important to weigh the investment against the environmental, health, and light quality benefits of solar tubes.

Issues:
When choosing a solar tube, several issues must be considered. First, look for the ENERGY STAR® label. This label indicates the solar tube truly works in the environmental-friendly fashion it should, and it could be used for federal or state tax credits. It's also important that the solar tube has some kind of moisture control so that water does not leak into the home. There are several extra features available for solar tubes that may desirable, including an electric light add-on that can be installed in the tube and used at night, a daylight dimmer to control the amount of sunlight allowed in, and designer diffusers to maximize light diffusion. Some companies also offer a softening lens instead of a dimmer for very bright climates. The actual look of the light fixture attached to the solar tube can also be customized to suit the aesthetic desires of a homeowner or business.

Regional Issues:
Solar tubes are technologically advanced, using advanced optics to draw as much light from the sun as possible. As such, they can function even in cloudy regions, during low-light hours, and in winter, although it is possible to draw more light in sunnier climates during the day. Look into details on the efficiency of different manufacturers' products in your specific climate before purchasing a solar tube.

Installation:
Solar tubes are simple enough that, in many cases, they can be installed by the homeowner. This can cut costs by almost 50 percent. Instructions often come with solar tube kits; however, a simple installation instruction video, "How to Install Solar Light Tubes," is available here. If the tube must be very long or must be bent through complex structures and is too difficult for the homeowner to install, professional contractors are available to install solar tubes.

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