Adam2 Posted August 9, 2019 Share Posted August 9, 2019 Well that was a surprise! Changing a window currently U for the 3G glazed element is 0.7. Why on earth would changing it to be opaque result in this changing to 1.2? I struggle to believe that a coating on glass can have such an impact but it has been stated by a supplier and this is what is in their quote so I thought I would check in here with others. Really appreciate your views before I go back and challenge them ? Link to comment Share on other sites More sharing options...
the_r_sole Posted August 9, 2019 Share Posted August 9, 2019 (edited) . Edited September 26, 2019 by the_r_sole Link to comment Share on other sites More sharing options...
craig Posted August 9, 2019 Share Posted August 9, 2019 (edited) That's a big drop, are you sure it's still triple? That's a double glazed Ug value in all honesty. Triple glazed, has the opaque glass in the centre, it doesn't have any coatings on it and the value for the glass is generally not massively impacted. It can go from a 0.5Ug to a 0.6 but generally it's the decimal place that will change (i.e. 0.52Ug to 0.55Ug for example) as well as the LT value, G Value changing but not a drop like that unless it's went to double. Edited August 9, 2019 by craig Link to comment Share on other sites More sharing options...
Adam2 Posted August 9, 2019 Author Share Posted August 9, 2019 No still 3G 4/4/4 with middle having a satin coating, warm edge spacer and argon. Didn't list the gap between glazing though but don't think that is the issue here Link to comment Share on other sites More sharing options...
Adam2 Posted August 9, 2019 Author Share Posted August 9, 2019 Thanks - I will get them to go back and check as your replies fit with my expectation also. Link to comment Share on other sites More sharing options...
craig Posted August 9, 2019 Share Posted August 9, 2019 I would need to see the glass specification sheet, what coatings they have used, spacers and gas used. Sounds wrong to me, satin finish is a "modern" alternative to patterned glass but it shouldn't impact the value by the value mentioned. Link to comment Share on other sites More sharing options...
Adam2 Posted August 9, 2019 Author Share Posted August 9, 2019 Thanks @craig I'm going back to them asking them to check and if they maintain it is 1.2 will ask for more detail on glass spec - though I'm expecting it to be the same glass spec as before (U0.7) with just the satin coat on the middle pane Link to comment Share on other sites More sharing options...
the_r_sole Posted August 9, 2019 Share Posted August 9, 2019 (edited) . Edited September 26, 2019 by the_r_sole 1 Link to comment Share on other sites More sharing options...
Conor Posted August 9, 2019 Share Posted August 9, 2019 We recently got multiple quotes for our proposed build, a few obscured 3G windows, no differences in U value that I noticed. 1 Link to comment Share on other sites More sharing options...
Adam2 Posted August 20, 2019 Author Share Posted August 20, 2019 Well after further discussion the supplier is adamant that the 3G windows will be negatively impacted by the satin coat as this means that the necessary energy efficiency related coating cannot be applied hence the change from 0.7 to 1.2. I struggle to accept this but there are only a few opaque windows so probably not worth any more energy on that with them. When I mentioned others quotes has the same U value for opaque units he questioned if they really did so seems they are pretty convinced on the subject. When I get the time will try and get info from a glass manufacturer. Ultimately they will be 3G so hopefully it is just a spec/interpretation issue. They did suggest krypton gas to improve U values but at a cost.... Link to comment Share on other sites More sharing options...
mvincentd Posted August 20, 2019 Share Posted August 20, 2019 I have 2 opaque units that are within 0.15 of their equivalent clear ones. (I do recall wanting ‘Low e’ glass for one of them due to its size and position, but was told it’s ‘either or’) Link to comment Share on other sites More sharing options...
craig Posted August 21, 2019 Share Posted August 21, 2019 You got the specs? I can run it through Calumen / gaurdian configurators. Link to comment Share on other sites More sharing options...
Adam2 Posted August 21, 2019 Author Share Posted August 21, 2019 8 hours ago, craig said: You got the specs? I can run it through Calumen / gaurdian configurators. Thanks - this is an opaque one 1500 mm x 1350 mm, Consisting of a Top Hung Window. ODC77 Colours: 76 7M16 Matt Anthracite grey Pré-ano Glazing: 1 x (4mm Clear Tgh/4mm Satin Tgh/4mm Clear Softcoat Tgh {W/E Spacer, Argon Filled} Triple Glazed) U g =1.2 W/(m 2 K) and this is a clear one for comparison 4476 mm x 1850 mm, Consisting of a Tilt before Turn Window and three Fixed Fields. ODC77 Colours: 76 7M16 Matt Anthracite grey Pré-ano Glazing: 4 x (4mm Clear Tgh/4mm Clear Tgh VTE/4mm Clear Tgh VTE {Blk Warm Edge, Argon Filled} Triple Glazed) U g =0.7 W/(m 2 K) ODC77 is a high insulating window system that meets elevated requirements regarding thermal insulation, stability and security. Anticipating on the thermal requirements, the insulation value (Uf) for the HI+ variant of this system goes down to 1.7 W/m²K for a standard opening window. The unique concept of the system makes it perfectly suitable for triple glazing and ODC77 even achieved the Swiss Minergie® component label. Link to comment Share on other sites More sharing options...
the_r_sole Posted August 21, 2019 Share Posted August 21, 2019 (edited) . Edited September 26, 2019 by the_r_sole 1 Link to comment Share on other sites More sharing options...
Gone West Posted August 21, 2019 Share Posted August 21, 2019 On 21/08/2019 at 09:41, Adam2 said: (4mm Clear Tgh/4mm Clear Tgh VTE/4mm Clear Tgh VTE {Blk Warm Edge, Argon Filled} Triple Glazed) U g =0.7 W/(m 2 K) I don't understand, have I missed something? I thought the only difference was that the centre pane was either clear or satin. Why has one got softcoat and are the spacers the same? 1 Link to comment Share on other sites More sharing options...
Temp Posted August 21, 2019 Share Posted August 21, 2019 Google found.. http://ravensbyglass.co.uk/wp-content/uploads/2016/08/satin-tech-sheet.pdf 4-14-4-14-4 argon filled satin glass in middle u-value 0.7 1 Link to comment Share on other sites More sharing options...
Jeremy Harris Posted August 21, 2019 Share Posted August 21, 2019 I've just checked the spec for the one window we have with an obscured glass centre pane. It's exactly the same as all the others, no difference in Ug, and has two low e coated panes. Looking at the orientation of the glass, it looks to me as if it's the flat face of the obscured glass that has the coating, which makes sense. I did this check using a laser pointer held at an angle and looking at the relative brightness of the row of internal reflections. Our windows are mainly 4 - 20 - 4 - 20 - 4, and Ug is stated as being 0.55 W/m².K I can't see any reason why obscured glass cannot be low e coated on its flat face, as it's no different to any other pane in that respect. 1 Link to comment Share on other sites More sharing options...
Adam2 Posted August 21, 2019 Author Share Posted August 21, 2019 47 minutes ago, PeterStarck said: 7 hours ago, Adam2 said: (4mm Clear Tgh/4mm Satin Tgh/4mm Clear Softcoat Tgh {W/E Spacer, Argon Filled} Triple Glazed) U g =1.2 W/(m 2 K) 7 hours ago, Adam2 said: (4mm Clear Tgh/4mm Clear Tgh VTE/4mm Clear Tgh VTE {Blk Warm Edge, Argon Filled} Triple Glazed) U g =0.7 W/(m 2 K) I don't understand, have I missed something? I thought the only difference was that the centre pane was either clear or satin. Why has one got softcoat and are the spacers the same? Warm Edge = W/E but something I can check with them. TBH softcoat I would expect to be in all units when I get their revised spec and pricing will check all have exactly the same detail or at least that I understand why it might differ. Also no idea on "VTE" Link to comment Share on other sites More sharing options...
craig Posted August 21, 2019 Share Posted August 21, 2019 7 hours ago, Adam2 said: Thanks - this is an opaque one 1500 mm x 1350 mm, Consisting of a Top Hung Window. ODC77 Colours: 76 7M16 Matt Anthracite grey Pré-ano Glazing: 1 x (4mm Clear Tgh/4mm Satin Tgh/4mm Clear Softcoat Tgh {W/E Spacer, Argon Filled} Triple Glazed) U g =1.2 W/(m 2 K) and this is a clear one for comparison 4476 mm x 1850 mm, Consisting of a Tilt before Turn Window and three Fixed Fields. ODC77 Colours: 76 7M16 Matt Anthracite grey Pré-ano Glazing: 4 x (4mm Clear Tgh/4mm Clear Tgh VTE/4mm Clear Tgh VTE {Blk Warm Edge, Argon Filled} Triple Glazed) U g =0.7 W/(m 2 K) ODC77 is a high insulating window system that meets elevated requirements regarding thermal insulation, stability and security. Anticipating on the thermal requirements, the insulation value (Uf) for the HI+ variant of this system goes down to 1.7 W/m²K for a standard opening window. The unique concept of the system makes it perfectly suitable for triple glazing and ODC77 even achieved the Swiss Minergie® component label. Ask them for the datasheet(s) from the glass supplier if possible. Link to comment Share on other sites More sharing options...
mvincentd Posted August 21, 2019 Share Posted August 21, 2019 22 minutes ago, JSHarris said: I can't see any reason why obscured glass cannot be low e coated on its flat face, as it's no different to any other pane in that respect. Indeed, maybe no reason but certainly Ideal Combi refused me a low-e/opaque combination saying either/or, so perhaps is worth people being alert to checking their chosen supplier does work with it. Link to comment Share on other sites More sharing options...
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