What is a Solar Tube (Let The Sunshine In)?

by Erik North on January 20, 2012

What is a Solar Tube (Natural Light is Better)


While CFL light bulbs are the current belle of the lighting efficiency ball, a number of other contenders have emerged. The shortcomings of CFLs have lead many consumers to look elsewhere. LEDs, halogens and ESL bulbs are alternatives with their own benefits and shortcomings. Today we will look at solar tubes. So what are solar tubes and how can they supplement your home lighting?

What is a Solar Tube?

With a funny name like ‘solar tube,’ it does create an evocative image. While the reality may not be quite that sexy, solar tubes are still pretty neat (that’s right, I said neat and I’m not a 50’s teenager).

Solar tubes are cylindrical tubes, usually metal, which help better bring natural light into your home. A solar collector dome is installed in the roof. When the sun is out, they transport light down into your house through reflective tube connected to diffuser dome installed in the room ceiling (appearing much like a recessed light without the attendant overheating problems).

Solar Tubes – Advantages

Because solar tubes use existing natural light, they have many positives. The quality of the light is excellent. Once big critique of CFLs is their harsh white light. Solar tubes bring direct natural sunlight into the room.

Conventional skylights, which solar tubes often replace can be an energy audit nightmare. They are very hard to insulate and air seal well. Solar tubes are much smaller and easier to insulate and air seal.

Anyone who has direct sunlight through windows knows that over time the sunlight will bleach the color out of fabrics. The light diffuser in solar tubes usually has UV coatings to filter out the damaging UV rays.

Folks suffering from seasonal affective disorder can enjoy natural sunlight in rooms without sunfacing windows. The redirected sunlight can even help with Vitamin D, produced by exposure to sunlight.

Since the sun does set, solar tubes can’t fully replace light bulbs, they can act as a supplement. Supplementing light use with a solar tube is a zero cost, zero emission way to light the room.

Solar tubes do have electric hybrid models which can light at night, allowing 24 hour use.

Lastly, because solar tubes are not electric, they work well in high moisture environments like an indoor pool or sauna.

Solar Tubes – Disadvantages

Yes, like any ride there are some drawbacks to solar tubes. The biggest, most obvious one is that unless supplemented with electric lighting, they can only provide light while the sun is up. Since that’s when folks are most often out or at work, it’s at cross purposes with it’s functions.

As a solution, there are various hybrid systems which supplement the solar lighting with electric light. I know I mentioned this just last paragraph but the first objection is always the night time lighting thing.

While there are less expensive versions, name brand solar tubes run around $600 – $700.

In lieu of a normal conclusion I wanted to mention the ‘Liter of Light’ project which is basically a budget version of a solar tube. In countries and areas without electricity, indoor lighting as we know it does not exist. The Liter of Light program repurposes discarded PET plastic bottles into solar light bulbs.

The bottle is filled with water and a bit of bleach, a hole is cut into the roof, the bottle is installed then water sealed around it. Voila, a solar light bulb for the price of scavenging a few bottles. Very inspiring stuff.

Here is the website: Liter of Light Website

Here is a brief video: Liter of Light Installation Video

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