# Window U-value and cost - is it worth it?



## rockofages (28 May 2010)

[Original post seems to have been deleted, so here we go again.]

Am looking at getting 3 old double-glazed aluminium windows and a similar patio door replaced with modern uPvC units.

I have a quote in writing of €3100 for a U-value of 1.3 on all, and for 0.8 it's an extra €500. The 1.3 is double glazed, the 0.8 is triple.

The house is 30 years old and has flip all insulation, something we are slowing getting around to fixing.

Can anyone tell me is the €500 extra for 0.8 worth spending over the 1.3?

TIA


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## notagardener (28 May 2010)

If as you posted the house is 30 years old and has poor insulation, would there really be any point getting triple glazing if you were to lose most of your heat through poor insulation in your floor, walls and ceiling. Triple glazing is obviously more popular in Scandinavian homes, simply because the weather they get is much more extreme. If you consider newly built homes in Ireland built to the latest building regs, double glazing is more than enough considering our climate.

I suppose the point I'm trying to make is, whilst with triple glazing has the advantage of better insulation, consider how much more it could cost to maintain or replace in the event of damage.  I'd be more inclined to go with the double glazing and sort out the other factors in the house that cause the house to be cold. Poor floor, wall, ceiling insulation, draughty door seals, letterbox, fireplace etc.  What would be the point in triple glazing if all surrounding factors were leaking heat.


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## rockofages (28 May 2010)

I spoke to an energy/BER surveyor today and he said to of course get the triple glazing. He put it very simply: 25% of heat is lost through windows and doors and triple glazing will make a difference. The rest of the house is being insulated/dry-lined bit by bit.


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## cbyr1983 (7 Jul 2010)

I got a uPVC door with all the bells and whistles, went for the composite as opposed to the normal one, triple glazed, etc.

It has no difference to my hall which is still freezing. 

Notagardener is right - put the money into your dry-lining, like I should have done.


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## Peter Sweeny (7 Jul 2010)

Check out (google) secondary acrylic window glazing, especially if the double glazed aluminium windows are in a good structural condition save for insulation value.

Significantly less expensive and gives an improved u-value and sound insulation.

Main downfall is that secondary windows will reduce the space inside the original window frame


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## rockofages (8 Jul 2010)

cbyr1983 said:


> Notagardener is right - put the money into your dry-lining, like I should have done.


I'm putting the money into both. An SEI grant should take care of the rest of the drylining - I have already drylined parts of the house with 70mm+12mm board, which has made a huge difference.


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## galwaytt (8 Jul 2010)

rockofages said:


> I spoke to an energy/BER surveyor today and he said to of course get the triple glazing. *He put it very simply: 25% of heat is lost through windows and doors and triple glazing* will make a difference. The rest of the house is being insulated/dry-lined bit by bit.


 
...a bit too simplistic, tbh, as it depends on how 'bad' the rest of the house is. Putting 'Über-windows' in a poorly insulated house will only make a % of a difference, esp if it has double glazing already......

Doing both, is best, but on it's own.............


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