Thermal bridgeing with Light Tunnels?

[Norbert]

I like the idea of a light tunnel into an internal upstairs corridor. I know it will work OK providing light, but if everything else is insulated and 3G to passiv house standards it seems like it could perhaps be the biggest thermal bridge in the house. Also could inturupt the run of PV on the roof.

 

Perhaps movement controlled LED lighting would be better and more efficient.

 

Has anyone else considered or had experience of this issue? Can you get helium filled 3G light tunnels?

[SteamyTea]

3 hours ago, Norbert said:

Has anyone else considered or had experience of this issue?

I did some work for Monodraught many years ago. They where importing a Canadian system. With most of Canada having very large season weather swings, maybe searching for problems 'over' there may reveal problems.

It is a shame that there is not a system that can be combined with the MVHR. That would cure half the problem.

Actually just thought of a way to cure most of it.

[Norbert]

If anyone else is interested I have found these :

 

https://www.lightwaydaylight.co.uk/products/blue-performance/

 

It says "Thanks to two types of Blue Performance, Lightway has become a definite standard in Germany for delivering sunlight to passive houses. Lightway sun tunnels have thus become the only ones in the world meeting standards for heat loss in passive and low-energy homes."

 

These appear to have double or triple glazed argon filled window installed in the roof insulation layer, so very low thermal bridging. Looks good!

Edited June 15, 2023 by Norbert

[SteamyTea]

1 hour ago, Norbert said:

These appear to have double or triple glazed argon filled window installed in the roof insulation layer

Is similarly to what I was thinking.

Light tubes, sun pipes or whatever you like to call them are really just a shiny pipe that allows light to be reflected easily. Nothing to stop that being insulated just like a water pipe.

While many have a clear acrylic dome in the top, there is no reason they cannot be a triple, quadruple gas filled bit of glazing.

The inside 'light' is just a shallow dome formed from semi opaque acrylic, but again, it could be a glazed unit.

A few years ago I made my own sun pipe to show someone. It was basically a half a periscope. Light came in the top, hit a mirror, then down a tunnel to a bit of semi opaque plastic.

Would be dead easy to incorporate into a new build.

I think I mentioned it to @pocster when he wanted to get some light into his dungeon. Then realised he would look up Scotsman's skirts.  The Gay Gordon's mean something different to him.

Edited June 15, 2023 by SteamyTea