Velux Sun Tunnels - Rigid vs Flexible

[Jeremy]

I've installed many sun tunnels over the years, and I have 2 more to do coming up in a few weeks. I've always installed the rigid ones since it seems to me they would transfer the most light to the interior. Last install I did was a major PITA due to the dome location relative to the difusser - the dome was behind the ridge of the house and the difusser was on the front side & I had to fit between a plumbing vent stack and a truss cord.

The next install I have will be easy for one of the tubes - it is a straight shot down. The second tube however will be similar to the last job I did. I'd like to use the flexible type for the difficult one, but have no experience with the performance of the flexible tubes. The flexible tube will have a light kit installed for night use.

How does the flexible tube perform compared to the rigid? The max length of the tube will be 7' & the flexible is rated for max 8'.

[VTNorm]

I have a flex tube to install but haven't done it yet. My immediate concern upon opening the box is that the material (mylar, maybe?) is super thin and looks/feels like it will tear if it just brushes up against something during install. I need to check for repair instructions before attempting the install.

-Norm

[Mark G]

I've installed mostly the flexible ones. They are 80-90% as bright as the rigid and much easier to install.

[James Eggert]

I have installed both; in my own house is one of the original SunPipe units.

The flex unit I installed I did not like. I felt the light loss was more than the literature says, and I was very unhappy with the end result.
I suppose the only way to know would be to use a light meter, which I don't have.

I simply will not use the flex unit again, BUT, if Jeremy install a flex as the conditions seem to require, I would like to hear the end result. The last flex I did, a Velux by the way, was 6 years ago! Maybe they were the early version and newer ones work better? I'll leave that fact finding to others!

[Lettusbee67]

I've installed about 60 of the rigid velux in both 10s and 14s. I recently installed 8 of the 20" commercial units, in the same building, with those being a mix of rigid and flex. Looking at the two side by side, you can tell the difference. Fortunately, they aren't side by side in the building, and no one will ever likely notice. The flex tubing does tear, and is easy to puncture. We just used heavy duty hvac aluminum tape, and patched the very small holes.

In a nutshell, the flex does the job well. The rigid does the job better. If I'm in charge of which to use, I will make every effort to use the rigid. But if flex is the only way to do it, so be it.

[Albion]

Was looking at these in the book Lowes today and found a conventional bubble sky lite cap is available but no custom flashing with it- darn. I keep wondering why no insulated version.

[Jeremy]

Thanks for the replies. I think I'll just stick with the rigid. It will be a PITA for one of the tubes but I rather not deal with tearing the tube.