How to find U value of already fitted wooden box sash double glazed windows?
Anonymous user 23/02/2024 - 3.48 PM
Is there an approved way to find and record the U value of the windows you already have? A machine you can hire or something?? (I've seen some for sale but they cost >£1000)
Wooden double glazed box sash windows, fitted early 2018 to replace rotting ones in a conservation area. Phoned the builder we used yesterday and he said he would have fitted Legend 70 with 5 multi-chamber system and gas filling. But paperwork just says "box sash windows with double glazing and draft excluders". (I know we should have checked at the time).
Turns out builder was not FENSA registered (which I now know we should have checked first). The council have been to see the windows as part of a regularisation application and said two windows need safety film and opening restrictors due to height, which we can sort, and they also need the U value.
Is there a way to record the U value of the existing windows?
Thanks in advance. I realise this would have been a non-issue if we'd done it properly at the start but I'm hoping we can somehow sort it.
Are you a tradesperson and able to answer this question?
I am sure there is a Web site that you can use to work out the U Value of existing fitted windows !.
Try looking up "Kanuf insulation", I'm sure they can help.
Do a search for u value calculator for windows and doors and a website pops up which will do the calculation for a fee. It is quite a complicated process where the cross sectional dimensions of each component has to be entered and the u value of the glass panel has to be known. You may have to submit for each size of window. Find out who made the windows ie the joinery shop the builder uses. It's a long shot but some joinery workshops use a software package called 'joinerysoft' this has an inbuilt calculator for u values the joinery company might have it. Good luck with this.Regards
Answered11 September 2022
1
Anonymous user
There is no machine to calculate the U value, it's a mathematical formula. There are indeed web pages where you can calculate the aprox U value however there are so many criteria you need to know and I really doubt you have them and I doubt anyone will issue a certificate without having any quality control certificate for your windows . In this particular case you need to ask your builder to provide you with all the paperwork for your windows he purchased or ask a company who produces the windows to provide you with one. There is no way you will get online a certified U value for the windows without an expert coming over.
If the windows are fitted as part of a project that’s being overseen by building regs, eg a loft conversion or an extension, then a Fensa certificate isn’t required as they will be signed off as part of the project.
With regards to the U value, the easiest option would be to contact the manufacturer as they would know exactly the spec they were built to.
Hope this helps.
