DanJepp Posted March 28, 2021 Share Posted March 28, 2021 Hi all trying to use the endless downtime waiting for planning to pick my cladding and windows etc — please excuse my ramblings but appreciate if anyone has been through similar thoughts We are going for a contemporary look with thin vertical Timber cladding and likely grey or black windows. My architect has steered me towards aluminum windows and Smart Aluminium being his recommendation so I’ve started looking here first, They do indeed have many profiles and in particular a flush version ( Alitherm 500) we like). https://www.smartsystems.co.uk/product/508/alitherm-500 Trouble is many of them are listed as having frame suggested UValues of 1.3-1.6. I’m aware the building regds enforce 1.4 as the minimum - The window sales person has mentioned this overall UValue can’t be brought down seemingly to any value required depending on the glass. I’m a little suspicious here but does anyone know what kind of calculation is used to calc overall window UValue once you add glass of a certain spec. Now I’ve read many posts and alu clad Timber seems to be many people’s choice and I’m guessing this is for the improved UValues.which I see are down into the 0.5-0.8 area. I’ve many more to look at (Rationel, Velfac,, etc) but From my initial look at idealCombi the sighlines do seem reasonable (53mm) which fit my modern brief but the frame depth seems huge ( I guess the strength comes from somewhere). We not fans of the dual colorings so the view of the windows at a slight angle shows the all important frame depth which is putting me off I’m also becoming increasingly aware when doing a self build how you can get carried away trying to hit and beat numbers - yes keen to be energy efficient and have no SAP/BC issues but also aware how good is good enough. Seems pointless to spend a fortune if the payback is a few pounds a year or repayment beyond my lifetime (Sorry Environment I’m trying but there is a limit) - Appreciate any thoughts thanks Dan Link to comment Share on other sites More sharing options...
ProDave Posted March 28, 2021 Share Posted March 28, 2021 Take a good look at Rationel aluminium clad timber windows (Aura plus) Lots of people on here happy with them nice simple frame profiles, and when i got quotes they were the cheapest of the 5 that bothered to quote. Link to comment Share on other sites More sharing options...
Mr Punter Posted March 28, 2021 Share Posted March 28, 2021 I have used Smart Systems in the past. You could look at Raynaers and Schuco as well. These are mostly all ali products IdealCombi, Velfac and Rationel are all from the Dovista group. Rationel are the most favoured by installers I know who do all 3. They are mostly all ali clad / composite products. Link to comment Share on other sites More sharing options...
nod Posted March 28, 2021 Share Posted March 28, 2021 16 minutes ago, ProDave said: Take a good look at Rationel aluminium clad timber windows (Aura plus) Lots of people on here happy with them nice simple frame profiles, and when i got quotes they were the cheapest of the 5 that bothered to quote. When I was getting quotes first time round A lot are not keen on self install Or didn’t quote bother to quote for Something that was 12 months down the line Where Ratiobel ok with self install Link to comment Share on other sites More sharing options...
craig Posted March 28, 2021 Share Posted March 28, 2021 (edited) Just remember one thing. The frame value is generally always the worst aspect, suppliers will compensate with a good Ug (glass) value to make it better. However, your still left with a poor Uf (frame value). Just because the overall Uw changes as a result, it does not mean your getting a “fantastic” product. Aluminium windows will generally struggle to get frame values below 1 unless your looking at the certified systems. Edited March 28, 2021 by craig Link to comment Share on other sites More sharing options...
DanJepp Posted March 28, 2021 Author Share Posted March 28, 2021 Appreciate your thoughts am I right in thinking any of the thinner Ali clad windows ( frame width/sight lines) will therefore have a significant wooden inner frame (depth) than pure Ali? the wife isn’t keen on black/ grey frames and white interiors so this leaves me with chunky black/grey wood inside which so far I’m not keen on! Assuming I can get the Smart Ali down to 1.3 (maybe lower) with better glass in real terms am I going to notice a difference with a 0.8 window? Appreciate lower is always better but at what point is it noticeable...... i know BR was 1.6 max previously so is 1.3 so bad - anyone else less worried about the window UV compared to the walls - I don’t have huge glass expanses thanks Link to comment Share on other sites More sharing options...
DanJepp Posted March 28, 2021 Author Share Posted March 28, 2021 5 hours ago, craig said: Just remember one thing. The frame value is generally always the worst aspect, suppliers will compensate with a good Ug (glass) value to make it better. However, your still left with a poor Uf (frame value). Just because the overall Uw changes as a result, it does not mean your getting a “fantastic” product. Aluminium windows will generally struggle to get frame values below 1 unless your looking at the certified systems. Thanks yes this was my guess and I may be OK accepting the overall value isn’t as good as it could be to suit the aesthetics. Would you recommend a target overal value to target that A) meets Building Regs and B) is better that large home builders would target for a budget perspective but low enough to make a noticeable difference and where quality/ feel starts? - Appreciate very subjective! Also, any idea how the overall UValue is calculated when better glass is added to a lesser frame? Window supplier may say X but I guess it’s me that faces off to building inspector so keen to know! Head is spinning with options and haven’t even seen the costs yet which I’m sure will be a huge discussion factor!!!!! thanks again Link to comment Share on other sites More sharing options...
Mr Punter Posted March 28, 2021 Share Posted March 28, 2021 The Alitherm 500 is pretty poor in terms of insulation. It can only achieve a Window Energy Rating of B and I guess this is for a large window with high spec glazing. Comparing window u values is difficult as it is dependant on the glazing and the window size. They should really give you the value for the frame (Uf). Smarts are a bit naughty and give you a U value for a window including glazing. Have a look at https://www.reynaers.co.uk/en-UK/product-selector-0 and you can have a play with various options for frame style, function, energy efficiency etc. They are open about their Uf values. Link to comment Share on other sites More sharing options...
gravelrash Posted March 28, 2021 Share Posted March 28, 2021 Have a look at Senior architectural systems (SAS).. they manufacture a system in ali called 'Pure' that meets passive in windows and .9uw in bi folds. Link to comment Share on other sites More sharing options...
ProDave Posted March 28, 2021 Share Posted March 28, 2021 6 hours ago, nod said: When I was getting quotes first time round A lot are not keen on self install Or didn’t quote bother to quote for Something that was 12 months down the line Where Ratiobel ok with self install Yes definitely. It was actually the builders that built the timber frame that installed them for me. 1 Link to comment Share on other sites More sharing options...
ProDave Posted March 28, 2021 Share Posted March 28, 2021 35 minutes ago, DanJepp said: Also, any idea how the overall UValue is calculated when better glass is added to a lesser frame? Window supplier may say X but I guess it’s me that faces off to building inspector so keen to know! It's UW value for each window that goes into the SAP calculations, that is all you need to worry about. Link to comment Share on other sites More sharing options...
nod Posted March 28, 2021 Share Posted March 28, 2021 11 minutes ago, ProDave said: Yes definitely. It was actually the builders that built the timber frame that installed them for me. That’s good to know Dave Rationel look really smart Also we will spend the extra money for 3G that wasn’t an option last time Link to comment Share on other sites More sharing options...
A_L Posted March 28, 2021 Share Posted March 28, 2021 1 hour ago, DanJepp said: Also, any idea how the overall UValue is calculated when better glass is added to a lesser frame? Window supplier may say X but I guess it’s me that faces off to building inspector so keen to know! BS EN 10077-1/2 https://passiv.de/former_conferences/Passive_House_E/window_U.htm Link to comment Share on other sites More sharing options...
Matt60 Posted March 28, 2021 Share Posted March 28, 2021 (edited) The window manufacturers need to pull their fingers out imo and sort this issue. Catnic have already done it - I'm having these (thermally broken metal lintels) and I don't see why the window manufacturers couldn't do similar. The first to do so won't be able to make them fast enough I expect... Edited March 28, 2021 by Matt60 Link to comment Share on other sites More sharing options...
ADLIan Posted March 28, 2021 Share Posted March 28, 2021 Decent window manufacturers will give the Uwindow value (for the whole unit). See also BFRC website for energy rating of windows. Link to comment Share on other sites More sharing options...
Conor Posted March 28, 2021 Share Posted March 28, 2021 We're going for 3g Internorm alucald PVC units, from my research best compromise of performance, looks and cost. We're going for a very light silver colour on the outside, and the standard white PVC on the inside. We both agree that dark grey has been done enough. Our worst unit is about 0.8 (small bathroom), and the best are under 0.7. Link to comment Share on other sites More sharing options...
volcane Posted March 28, 2021 Share Posted March 28, 2021 56 minutes ago, Conor said: We're going for 3g Internorm alucald PVC units, from my research best compromise of performance, looks and cost. We're going for a very light silver colour on the outside, and the standard white PVC on the inside. We both agree that dark grey has been done enough. Our worst unit is about 0.8 (small bathroom), and the best are under 0.7. Who is providing your windows? 3 years since we ordered ours and Internorm were the best option for us also. Link to comment Share on other sites More sharing options...
DanJepp Posted March 28, 2021 Author Share Posted March 28, 2021 3 hours ago, ADLIan said: Decent window manufacturers will give the Uwindow value (for the whole unit). See also BFRC website for energy rating of windows. To be fair to smart they just make the profiles for other window companies - ali fenestrations I think they call it Link to comment Share on other sites More sharing options...
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