"Sun Tunnel" skylights,anybody have one?

I need to brighten an extremely dark and gloomy foyer.Dimensions 12’ by 12’ cathedral ceiling.I was tossing around the idea of installing one of the many “sun tunnel” type skylight products.Anybody have any experiences with them?

what is a sun tunnel skylight?

They had them at University of Minnesota, where one of the buildings was almost entirely underground to save on heating bills.

It’s a very classy effect if done right.

Sure beats a non-solar ceiling.

It is a tube of highly polished aluminum one end of the tube penetrates the roof…the other penetrates the ceiling.
Both ends are sealed,the effect is to literally pipe in sunshine.

Rich G7subs:

So you’ve got the sun shining through aluminum? Is this the “transparent aluminum” Commander Montgomery Scott taught us the secret of back in Star Trek IV?

He said a tube of aluminum, not a cylindrical block. Any light that enters the hollow tube reflects off the inside surface repeatedly, and eventually reaches the other end of the tube. Sounds very simple and effective.

By the way, do they have some sort of a concentrator mirror or lens on top?


My parents have several of them in a hallway—very similar situation to what you’re thinking about. IMO, they work very well, and really brighten up the space during the day.

It’s like a new twist on the old deck prisms on ships.

In fairness, I must point out that the light is natural sunlight, and as such is subject to whims of cloud cover etc. It doesn’t sound like that big a deal, but it can be a little odd having the lights suddenly dim, then brighten…then slowly dim again…as you’re walking down the hall. Of course, maybe you’re going for the ersatz fun-house effect. My father is fond of saying that every time he’s walking down the hall and a cloud rolls by, he thinks he’s having a stroke. Dad’s a real cut up.

I recommend the sun-tube-thingies. Mom and Dad’s have been there for 3 years without a hint of trouble.

Thank you, and Goodnight.

I’m thinking about putting some of these in my house when I build it, so I’ve looked at some Solatube-brand products in the showroom. Even on a relatively cloudy day, they seemed to work well–and they are available with an optional lighting kit for night/cloudy conditions.


I know that! But he also said it was sealed at the ends, which…okay, nevermind.

What sort of diameter are we talking about? Is it difficult to seal the roof against leaks with these things?

Yup…sealed by a plexiglass dome on the roof…14’’ dia. tube.Supposed to have some kind of “solar collecter” lense to concentrate and focus the light on the roof end,the other end has a diffuser lens to soften and spread the light.It’s supposed to light up 250 sq ft.
Thanks for your input Jingo…I think I’ll order one.Kinda pricey though.(480$ for my application))

What added feature would produce a camera-obscura effect - and project an upside-down image of the outside in your interior walls?

If the ‘sun tunnel’ was horizontal and installed in the wall, you mean? Not much, just a set of lenses. However, the image would be very dim because the light caught by the small lens is spread over the entire wall. The only way to make it brighter is to make the lens larger, but eventually the lens will become so big that it takes up most of the wall, defeating the purpose. You might as well put in a normal window.

Come to think of it, a periscope-shaped system can be made with a set of lenses and two mirrors, to pipe the outside view through a tube in the ceiling into an underground home. Or for more flexibility, use a bundle of fiber optics, like the endoscopes doctors stick in your nose or throat. You’d still have the same problem though, it would be extremely dim.