# Double V’s triple glazing



## selfbuild (6 Dec 2011)

Hi all
I am in negotiations with a window supplier for windows for my new build.  Am going for a foam filled pvc frame which is certified as passive (to Passiv Haus Institute certification requirements)
The only thing to decide is double (u value of 1.1) V’s triple (U value of 0.8) glazing – there is approx 2000 euros difference in cost
I was thinking of Triple glazing as the U value is better and it would reduce noise coming from a nearby road – but I’m not sure if these justify the additional cost as the double glazing already provides a very low U value already – anyone got any advice on which to choose?
Thanks


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## threebedsemi (6 Dec 2011)

Your BER assessor can run both options through the deap sofware and tell you what the estimated additional savings are for the triple glazing. These are unlikely to amount to a great deal but the payback time will dictated by orientation, amount of glazing, etc so its impossible  to comment without knowing the house design, orientation, etc.

As far as i know, no double glazed window units arepassivehaus certified, so double check this with the supplier. 

The main advantage with triple glazing is that the internal surface temperature will be 2-3 degrees warmer than the double glazing equivalent. This becomes important if you have large areas of glazing, or glazing beside an area where you are likely to be sitting etc. You will feel warmer sitting beside a triple glazed window, and might be inclined to tuen your heating down by a degree or two as a result. This kind of saving cannot be estimated by the deap sorfware...


www.studioplustwo.com


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## lowCO2design (7 Dec 2011)

no DG units are to passive standard. 
may I add that the window installation details (thermal bridging/ insulation overlap), air-tightness, and the overall U-value of the unit that comes with certification is of the utmost importance. 

if its a busy road, then for that reason alone, stop messing about and put in the triple glazing. the certification of the passive house institute is by far the best available in ireland..  do insist that your builders use their installation details and get your architect to seek the appropriate guarantees and check the installation details are as good as they can be.


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## lowCO2design (7 Dec 2011)

threebedsemi said:


> This kind of saving cannot be estimated by the deap sorfware...


it can in the passive house software


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## Troy McClure (11 Dec 2011)

selfbuild said:


> Hi all
> I am in negotiations with a window supplier for windows for my new build. Am going for a foam filled pvc frame which is certified as passive (to Passiv Haus Institute certification requirements)
> The only thing to decide is double (u value of 1.1) V’s triple (U value of 0.8) glazing – there is approx 2000 euros difference in cost
> I was thinking of Triple glazing as the U value is better and it would reduce noise coming from a nearby road – but I’m not sure if these justify the additional cost as the double glazing already provides a very low U value already – anyone got any advice on which to choose?
> Thanks


 
Make sure there is metal reinforcement within the frame rather than the company achieving the U value by removing it.


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## babydays (1 Jan 2012)

Troy McClure said:


> Make sure there is metal reinforcement within the frame rather than the company achieving the U value by removing it.




Could you further explain that? I'm also looking into a large area of glazing .


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