Then there is the old saying: "There are really only 2 types of skylights, those that leak and
those that will leak"

What I like about the light tube is is ability to bring Natures sunlight into a otherwise dim room. I bet the atmosphere is real nice using one, much like a skylight does.

Skylights need to be installed by a competent person or your going to have issues , We had one in a house that some friends installed (who had starting a renovation business) that never leaked in 10 years.

Then there's my neighbor who had to rehire people to fix it when some buyers home Inspector noted the flashing was done incorrectly as well as the roofing around it.

Its hard for anything not to leak when people like Bozo the Clown install it.

Just registered. Came over from ecomodder. I know this is an old thread, but I thought I would add my experience with Velux solar tubes.

We put in a second story addition about 12 years ago. I purchased three solar tubes to give interior light. Two 10 inch tubes, purchased from Lowes, for a long dark hallway and a 21" hybrid system purchased from a cooperative local Velux dealer, from whom I also bought a couple of skylights for a stairway.

The 10" were for the 45' hallway in the addition and only had to go to the low-sloped roof. They work great. I could have gotten by with one. The 21" was for the ground floor kitchen, which had windows only into a breezeway. The previous owners had installed a cheap rectangular bubble skylight which lit the space quite well.

The addition put a 12' run to the roof. It was recommended that, while a 17" rigid tube might be sufficient, a 21" rigid would assure plenty of light, so I went for the 21". The only complication was that there was no 21" rigid for residential applications, so I had to cobble together a 21" residential flex tube kit with some rigid tube sections for a commercial installation. It wasn't particularly difficult and it puts a lot of light into the kitchen. I used sections of the flex tube to fit the rigid tube to the residential skylight and diffuser. I designed a chase into the second story floor plan adjacent to a hall closet.

Are they cost-effective? I don't care. I wanted natural light in otherwise dark spaces. I didn't feel that they were overpriced (the 10" kits were on sale), and given the cost of everything else in the addition and remodel, the solar tubes and skylights were not significant items in the budget.

I have checked around recently and the technology has advanced considerably in the intervening years. Supplemental lighting with LED arrays and light sensors can automatically adjust output to assure consistent light. You can also install automatic blackout shades (as was mentioned, even moonlight can brighten a space at night). I may try to upgrade my diffusers in a few years with this new technology.

Some advice, make sure you seal the tubes and connections thoroughly. I didn't and I get sun-roasted box-elder bugs in my diffusers that I have to clean out every few years. Given the nature of the beasts, I am uncertain that even properly sealing would work, as there are ventilation holes (don't block them) that would provide access.

Also, I had to install additional screws into the 21" skylight, as the number recommended in the installation instructions proved insufficient to keep the dome attached to the collar in a strong wind (a very strong wind). Fortunately, that lesson did not involve rain, snow or dust. I added screws to the other two tubes, just to be sure.

I installed my tubes and skylights into a new roof. I don't know as I would be enthusiastic about retrofitting them into existing roofing, but I haven't heard of any complaints from neighbors that have.

I have seen a youtube of a diy'er who tried to make his own solar tube using old mirrors. It didn't work. He would have been better off spending a little more (possibly less) and bought one from the big-box store or the internet. I think that a decent solar tube could be cobbled together by a diy'er but I don't know as it would be worth the agony.