Energy & Sustainability Furniture & Lighting
Natural alternatives to on-demand lighting

Here’s a brief overview of non-oil light-producing options from the authors of The Carbon-Free Home. In part:

Increasing the natural daylight in your home is something to take into consideration if you find from your energy diary that you need to turn lights on during the daytime. We are fortunate that our house, designed in the 1930s, has no issues with dark rooms. Every bathroom has a window and every hall has natural light. But some condominiums, apartments, and splitlevel or ranch houses we’ve seen have a serious lack of daylight.

Sunlight pipes (also called tubular daylighting devices) are low-tech devices that work wonders in dark hallways or bathrooms that have an accessible roof to penetrate. Be careful: every time you make a hole in the roof there is a chance for water penetration and damage. Solar tubes must be carefully installed and the flashing and caulking checked regularly.

(via Chelsea Green)

From one of the manufacturers, here’s a diagram of one such solar tube:

solatube.jpg

(Image via Sunpipe)

And, here’s an article on installing solar tubes.

Has anyone created their own version of a solar tube? Other than finding a high-quality plastic dome, reflective film for the interior (mylar?), and making sure you don’t create a nice water inlet along with your light tube, is there any reason not to try and homebrew this?

12 thoughts on “Natural alternatives to on-demand lighting

  1. I don’t have any myself but back in my undergraduate days, I spent a summer researching them for a professor in the Environmental Design department of the University of Calgary. A few things I recall from that research:

    1) At the time (we’re talking the late 90’s) you could get some systems that used a flexible tube (like your dryer vent). These were the least effective as surfaces were about as far from flat as you’ll find and a lot of light got reflected anywhere but down into your house.

    2) Avoid elbows if you can. You typically need more than one to jog around something. These are mostly just heating ducts with a reflective coating on the inside and those elbows are designed to easy adjust the angle, not reflect light. As I recall, each elbow had a significant effect on the amount of light transmitted.

    3) Get as wide a tube as your house will manage. I think you can typically find 16 and 24 inch units. Get the biggest unit your house will handle. Don’t cut rafters to make it fit though, the money you save on lighting will not come close to what it costs to rebuild your roof ;)

    4) At the time the systems came with extra “light scoops”. Things work better with the scoops. One system had a huge “bonnet” that sat outside the dome which had a massive impact on the amount of light getting in but would be far more susceptible to the weather. Another had a little cap that sat inside the dome which did OK and didn’t bother with the weather.

    Now if you want to build your “own” system, I’ve always thought that one of those old satellite dishes nicely chromed (or covered with mylar) with some sun tracking software and bundle of fiber optics focal point where the antenna would be could do a much better job.

  2. Wow…ever have those days where NOTHING posted applies to your interest? Me too, but today is the opposite!! :)

    The solar tubes are quite popular where I work. The 16 and 24 are the most common, with multiple 12’s in some houses.(sizes are my guess)

    All seem to be a “straight shot” with no large angle.

    No ‘scoops’ that I know of.

    The 24″ let some radiant heat in, you feel it below them. Not so much with the 16 and 12.

    As far as rolling your own… checking ebay gives a $175-$250 range for the 10/14″ kits. Yes, a MAKEr could create one. But the potential damage you get during the learning curve…Try it on the barn for a few years first!

  3. to Adam V (et al) i lived in a south american country, solatube and others are a little out of budget for most of ours, so I was thinking some time in a diy solar pipe, had you investigate or resolve about the reflective coating? I looked for mylar here without luck … had you found different methods to reflect light inside the tube?

  4. I’ve been interested in a remake of this for the handyman as well. By the way, most american rafters and ceiling joists are 1 1/2″ wide and spaced 16″ or 24″ on center, so a tube either 14″ or 22″ in diameter would be in order.

    I was thinking about a round bedroom type ceiling light diffuser, although these often have a hole in the center, it could be plugged easily enough. Also, the highly reflective solatube extensions are available about 3 or 4′ long for about $30 or $40 if I remember correctly.

    Worst case, you could get 12″ or 14″ diameter metal air duct and epoxy glue some aluminum foil to the inside. Trying to get a minimum of wrinkles. Any glue would have to last for many years and put up with high attic temperatures.

    The illustration shows the storm collar as the “primary flashing”, but this is actually the secondary flashing or what is called counterflashing in the trade. You can almost do without the storm collar if you like to live dangerously, the pipe is small, and there is little or no snow.

    The diffuser at the bottom helps spread the light throughout the room, but is optional. A flat piece or two of plexiglass would also work.

    Be careful of parabolic reflectors and combustible roofs!

    Gary Wheeler, AIA, LEED AP, Architect

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Luke Iseman

Luke Iseman makes stuff, some of which works. He invites you to drive a bike for a living (dirtnailpedicab.com), stop killing your garden (growerbot.com), and live in an off-grid shipping container (boxouse.com).

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