March 21, 20251 yr We are due to start building a highly insulated 1.5 storey detached annexe in July. The downstairs wet room of approx. 4m2 is due to be lit by a small Velux in the roof at the edge of an upstairs. bedroom. I now need to use this area in the bedroom behind a bulkhead for MVHR pipes. My wife wants to have natural light in the wet room so she is suggesting a sun pipe. For me this will only work if it is well insulated otherwise condensation, due to cold bridging, may be a problem. We will have a number of Velux's on the roof so I thought that perhaps a Velux sun tunnel may work. However, these have a basic u-value of 2.9w/m2/k, though they do an insulation kit which drops the u-value to 1.8w/m2/k but only for the 14" version which would be too large for the size of the room. Has anyone used a Velux sun tunnel in a bathroom environment? and if so was there a condensation issue? Or does anyone have any other suggestions? Edited March 21, 20251 yr by Smallholdertoo duplicated image
March 21, 20251 yr 6 minutes ago, Smallholdertoo said: Or does anyone have any other suggestions I did some work for Monodraught back in the 1990s. They were decent to deal with.
March 21, 20251 yr Author 59 minutes ago, SteamyTea said: I did some work for Monodraught back in the 1990s. They were decent to deal with. Many thanks I will contact them on Monday
March 21, 20251 yr 2 minutes ago, Smallholdertoo said: Many thanks I will contact them on Monday Let us know how you got on. I often think about sunpipes, still have some prototype bit kicking about.
March 25, 20251 yr Author On 21/03/2025 at 20:56, SteamyTea said: Let us know how you got on. I often think about sunpipes, still have some prototype bit kicking about. Contacted Monodraught. They agreed that their Sunpipe is not designed to be airtight, Solatube however do have a passiv house standard version of their product that has 0.5w/m2k u-value and gaskets to ensure that airtightness. So I am probably going down this route.
March 25, 20251 yr 1 minute ago, Smallholdertoo said: They agreed that their Sunpipe is not designed to be airtight I think they use the lack of airtightness to control condensation, they are/were an HVAC company really. Have you thought of making your own, it is only a periscope after all.
March 26, 20251 yr Author 11 hours ago, SteamyTea said: I think they use the lack of airtightness to control condensation, they are/were an HVAC company really. Have you thought of making your own, it is only a periscope after all. In a word No! Although it s only a periscope of sorts , it needs to be a1rtight and thermally functional and aesthetically attractive both internally and out. Maybe worth the effort if i needed 5. Thanks for your help. Edited March 26, 20251 yr by Smallholdertoo Minor wording change
October 27, 20251 yr @Smallholdertoo I would be interested to hear how you got on with this - I'm looking for a similar thing.
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