Solar tubes – conduits of sunlight
Solar tubes are cylinders used to bring natural light into homes, to help replace or add to electric lights. They’re also known by several other names, including sun pipes, sun scopes, light tubes, and daylight pipes. They’re usually installed on roofs and come through to the ceiling below (like a skylight, or like the periscopes we’ve all seen in old movies with submarines), and they look like small spotlights.
The concept of solar tubes isn’t new– similar devices were even used in ancient Egypt. The most common form uses reflective material inside the tube to help amplify the light inside the room below. A clear dome at the top of the tube lets sunlight in. Inside the house, a diffuser spreads light in the room. The light will be brightest if the tube is short and straight.
Other systems use more complex technology, like optical fibers or fluorescent polymer layers. Light tubes using technology that follows the movement of the sun have been installed in places like a subway station in Berlin.
Why not just use a window?
Like skylights, solar tubes provide light coming directly from above, so you’ll get more sunshine. Solar tubes are better insulated than skylights or ordinary windows, though you won’t be able to see as much of the outside world. For interior rooms without outside walls, they can be a great source of natural light. Because of the way the technology works, they can actually provide much more light than a skylight that’s many times larger. For people with seasonal affective disorder who need more access to sunlight, they can help supplement existing windows. Solar tubes can also be useful in rooms that require high-security– probably not an issue in your home, but useful in places like a police cell where regular windows could make it easy to escape.
Other benefits of solar tubes
Electric lights use energy, and even if you have solar panels on your roof, it’s a good thing to save energy. Natural light also benefits health in ways that artificial lights don’t. Since solar tubes don’t require electric installation, they can also be useful in wet areas like bathrooms or rooms with indoor pools.
The economics of solar tubes
The price of solar tubes will vary depending on your location, the type of roof you have and the various features you choose, like an exhaust kit for a bathroom or a daylight dimmer that allows you to “turn off” your solar tube. A brand-name solar tube could cost around $700, including installation and sales tax, if you have a standard composite shingle roof.* You may also be able to claim a federal tax credit and various state and local incentives.
* This is based on information from solatube.com.