Need advice on Windows

LithiumKid1976

hi
we hope to start building our house shortly.

obviously we are hoping to get the most energy effiecient windows.

im confused though by all thats out there.

1. Is there much benefit in getting triple glazing over double glazin?
2. How Much notice do we need to take on u Ratings for windows?
3. Is there any benefit in using aluminum framed windows over timber framed ones?

Regards
Damien

muffler

Moved to the main C & P forum.

Nathan Power

LithiumKid1976 wrote: »

hi
we hope to start building our house shortly.

obviously we are hoping to get the most energy effiecient windows.

im confused though by all thats out there.

1. Is there much benefit in getting triple glazing over double glazin?
2. How Much notice do we need to take on u Ratings for windows?
3. Is there any benefit in using aluminum framed windows over timber framed ones?

Regards
Damien

Hi Damien

1: A typical 24mm double glazed unit consisting of two 4mm panes separated by a 16mm Argon gas filled cavity, and with one Low-E pane, will have a centre pane u-Value of about 1.1W/m²K. Without the Low Emmisivity glass and Argon gas, this unit would only achieve 2.9W/m²K ! A triple glazed 42mm unit ( such as we use ) with two Low-E panes will have a centre pane u-Value of 0.7W/m²K. This triple glazed unit would be constructed as follows:
4LowE-16-4-14-4LowE

Of course you have to have a frame that can accept such a wide unit, but as you can see the triple-glazed unit in this case is over 30% more efficient.

2: It is important to take notice of u-Values when comparing prices from different companies. Make sure the u-Value quoted is certified, and is the total window u-Value, and not simply the glass u-Value.

3: This depends what your priorities are. Aluminium windows require little or no maintenance but it is much more difficult to achieve a good u-value compared to wooden windows. Wooden windows are also produced with aluminium cladding on the outside, to reduce maintenance and keep u-values low. Most suppliers of wooden windows will also give you a quote for Alu/Clad windows. Just make sure that their Alu/Clad system is not externally beaded, as I have seen some companies offering this and it is not a good idea due to the security issues it creates.

Cheers,

Nathan

gerry28

Hi,

In an ideal world triple glazing would be great, having just complete my own house the most important thing to do is ensure your blocklayers put the insulation in correctly. I had to open a wall recently and I noticed there was insulation missing, on other parts they didn't bother putting insulation behind the window sill.
Lazy blocklayers will cause your house to lose far more heat than you would gain from upgrading to tripple glazing.

LithiumKid1976

Thanks for the info guys.

Think we will be going with the argon filled double glazed option. i visited a friends new build yestreday, he has it very well insulated, he pumped the cavity, used insulated slabs, and some sort of anti draft material around the windows. couldnt get over the benefits, he was only heating the house with geo-thermal with underfloor, and it was perfectly warm....and its still only being built.

will try to follow his lead....