A few weeks ago I was flipping through a recent issue of Home Power magazine and I stumbled upon an article abut solar tubes. (Sorry, I would provide a link to the article but they don't make it available online.) Solar tubes are not new technology, but there has been some pretty amazing improvements in recent years. The author of the article had installed a Solatube in his office and was very pleased with it. Shortly after this we ran into Solar Midwest while we were at the Living Green Expo. They had the Solatube units on display and I got to ask a ton of questions. Shortly after that I got a quote and decided to get one installed. The basic principle of the Solatube is exremely simple. You mount a light collector on your roof. You then run a 10" or 14" tube that is exceptionally reflective to a room in your house. There are three main areas of technical focus. Making the collector dome as efficient as possible, losing as little light as possible in the tube, and distributing in the room in an even way. This diagram from Solatube's website sums it up well.
The advancements in the collector dome and the efficiency of the pipe are incredible. It can collect light all day, picking up even dull light on a cloudy day. There is no need for direct sunlight. The tube itself is extremely efficient and loses very little light.
Let me skip to the after shot. Here is the room with the Solatube.
The effect is shocking. This room was one of the more poorly lit areas in our upstairs, and now it is as bright and enjoyable as the most windowed areas in the house. Note the relative sizing of the Solatube versus the cans next to it. This is the 14" unit and it delivers a whopping amount of light. Tammy and I are both very pleased with it and are thinking we will likely have two more installed at some point in the future.
Some FAQ items to share with everyone, in no particular order:
Does heat transfer through it?
Surprisingly no. The Solatube itself is just sending the light. The heat part doesn't make it down.
What about storms?
I felt the dome, and it's impressively thick. I'm not sure exactly what would take it out, but I'm very confident the roof around it would have issues before the dome itself cracked.
Is it ugly?
It's another thing on your roof, so you may not like that. We were able to install it in a location that is completely invisible.
Due to this great placement you cannot even see the dome from the street. I don't think it would be an issue even if you could see it.
Does it save energy?
Well, it depends. If you have rooms that you use lights during the day it definitely would. Our situation was more of a luxury since we like a lot of light and this room was just dimly lit. We didn't use lights there that much during the day, but it was drab. Now it's bright and full of light.
Great locations for this technology would be a windowless bathroom, or a closet. Those are the locations we are considering for a future use. Or frankly anywhere you want nice, full-spectrum sunlight.
Would you recomment Solar Midwest?
Yes, they did a great job through the whole project. As a bonus, all the pre-sales activity was via email which I appreciated.
What about basements?
To me the killer utility of solar tubes is in the basement of a house. This is easily done in a new build, but nearly impossible in an existing house due to the tubing required. I can only dream of the day when I pipe a bunch of natural light into the lower level of a new house.
Can you see moonlight?
Yes. There is a cool bluish glow on a full moon.