Tue, 19 Dec 2023 08:38:20 +0000 http://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17752&Focus=300410#Comment_300410 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17752&Focus=300410#Comment_300410 Thu, 23 Feb 2023 16:22:55 +0000 luz13827
We had a poorly manufactured and installed glazing facade installed last year, and are currently in process of making a claim against them. They claimed a U value of 1.3, but they left such 3-4cm large gaps around the glazing (which they then filled with foam) that I am sure it's not 1.3 in reality.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17752&Focus=300415#Comment_300415 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17752&Focus=300415#Comment_300415 Thu, 23 Feb 2023 18:54:26 +0000 Doubting_Thomas
You can buy the equipment for around £3k (https://www.buildtestsolutions.com/u-value-measurement/iso-9869-measurement-system) and there are professionals with this kit who offer such a service.

Since the measurements are just done with a temperature sensor on each side (as opposed to, say InfraRed), I would have thought it would be the same approach in principle to test a window and frame.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17752&Focus=300416#Comment_300416 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17752&Focus=300416#Comment_300416 Thu, 23 Feb 2023 20:25:31 +0000 RobL
So Ug=7.7 * (Ti - Tg) / (Ti - To)

When measuring the temperatures, use the same IR thermometer, point it at a piece of paper inside to measure indoor air, and stick a label on the window to get a good temperature of it. We want outside air, not ground or night sky, so again measure something lightweight. It’s best to do it when it is cold out, and get all the measurements at the same time so the thermometer doesn’t drift much.

If it’s 20C in, 0C out, I think a U value of +-0.3 is plausible accuracy, easily enough to determine ‘modern dg glass’ versus old.]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17752&Focus=300423#Comment_300423 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17752&Focus=300423#Comment_300423 Fri, 24 Feb 2023 11:01:41 +0000 fostertom Posted By: luz13827They claimed a U value of 1.3, but they left such 3-4cm large gaps around the glazing (which they then filled with foam) that I am sure it's not 1.3 in reality.That's going to be difficult - the U-value for the whole will be a composite of centre-pane, edge-of-pane, frame and foam packing U-values. How will you apportion or weight those to get a value for the whole?]]> http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17752&Focus=300430#Comment_300430 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17752&Focus=300430#Comment_300430 Fri, 24 Feb 2023 18:08:16 +0000 djh