Acoustic Windows

[AndySussex]

I currently have single glazed windows that are leaky, thin and noisy since the house is about 4 metres from a busy busy road. The plan is to replace them in the New Year and my priorities are a.)Noise reduction, b.) Warmth (in this order of priority).

My research thus far suggests that this is the best approach:

Double Glazing
Laminated Acoustic Glass
Different thickness of the two pieces of double glazing 12mm and 8mm or 8mm and 10mm (definitely different thickness to avoid resonance)
Noise insulated window frame
Large gap between panes circa 100mm

Drawbacks would appear to be that the seal can give out more easily when you have different thicknesses of glass but I suppose this is a compromise to take since the different thicknesses should help with the sound waves.

I am new to all of this so any advice/tips are much appreciated, particularly with experience!

[MarkB]

Large gaps of the order of 100mm between panes are almost certainly not viable. The gas would be able to have convection currents carrying the heat from warmer to cooler panes and destroy the thermal benefits. Fine if it's an internal partition, like in a recording studio, but no good as an external window. In reality 16mm or 18mm is about as big as you can go with Argon fill.

Internorm have a variety of options for acoustic glass and do have a chart showing the options along with the noise attenuation. Might be worth talking to your local Internorm distributor for the chart. While different glass types/thicknesses and gap sizes make a difference it's relatively small overall.

There is a demo done by one of the main stream performance window manufacturers of a stereo inside a cabinet made of 3G windows. The sound reduction between windows open and closed is massive. If you're after a recording studio then you might need something more extreme but for day to day, a good quality 3G window with different glass and gap thicknesses is probably good enough.

[AndySussex]

Ah sorry - meant 10mm but 16mm would be cool.
Do you know about the 'lastability' when you use different glass thicknesses?

[MarkB]

Ah sorry - meant 10mm but 16mm would be cool.
Do you know about the 'lastability' when you use different glass thicknesses?

I do have a friend with 2G windows with different pane thicknesses for acoustic reasons. He has had them some time and as far as I am aware he hasn't had any problems with them. I can't see why it would be a problem.

[dhaslam]

The main thing is to have as wide as you can get  and don't have opening sections unless you have to  for fire escape or other reasons.   

[Ivan]

I live about 15m from a busy dual carriageway. The original single-glazed window was very noisy. The biggest difference was made by adding secondary glazing - about 10" away from the main window. My neighbours house has average double glazing and it was a lot louder.

A while ago, I replaced the single glazed unit with a triple-glazed unit (overall thickness 44mm - so I think that's 16mm x 2 cavities), with argon in the cavities. The result is almost no noise at all from the dual carriageway. The triple glazing is definitely a lot quieter than the double glazing on a similar window upstairs.

[AndySussex]

Thanks Ivan. So you had 4mm glass (*3) with 16mm argon filled gaps.
Do you have the secondary glazing still, in addition to the triple glazed?

My windows are pretty small so I'm not even sure if I'd fit through them, but is there some kind of H&S requirement to have at least one that opens of a certain size?