Noise/Sound-Reducing Windows (Glazing)

Ken_K

Noise isolation properties of upvc windows depend on a brand (frame and glass). When you getting upvc windows make sure that you are able to see a frame cut because frame should have a lot of chambers or it should be filled with foam (by manufacturer). Keep in mind that the best insulation properties are provided by laminated glass.

Nick_D_2

Hello all,

I am an acoustic consultant, so I'll try to shed a little light on this subject.

Firstly, be very careful of any sales gimmicks for 'acoustic' glazing. There is no one specification suitable for every application. The glazing specification for noise reduction is dependant on the following factors:

1. The existing noise impacting on the external facade (obviously!)

2. The area of glazing (larger areas will be worse than smaller areas)

3. Room dimensions and absorption (i.e in a small empty room the noise may be worse than that in a large room full of furnishings)

A salesman will certainly not consider these factors (or have the knowledge how to) therefore there is a risk when selecting any old 'acoustic' glazing that you might end up with:

1. Over specified glazing, costing you the earth

2. Under specified glazing, and noise is still an issue

3. The glazing performance is suitable, however the noise reduction is undermined by trickle vents (common!)

There are proprietary acoustic trickle vents, however these only offer marginal noise reduction performance and would not be suitable for houses located near particularly noisy sources, such as major road and rail networks, city centres or underneath airport flight paths.

This would mean the dwelling would need to be ventilated mechanically, thus not requiring any open vents. This is common of new build dwellings in noisy areas. If you want to learn more about ventilation see Approved Document F.

Usually it would be just the glazing and vents that are the significant elements of noise ingress, however in some cases of very high noise levels other building elements such as wall and ceilings may also require treatment.

Therefore my advice is to ask an acoustic consultant (see Association of Noise Consultants web site to find a local consultant) to undertake a noise survey and calculations to determine a suitable specification, if you can afford this. If your wanting to sound insulate a whole house this would be worth while, but would not be cost effective for a single window!

A single pane of glass can actually perform better acoustically than a double glazed unit, likewise triple glazing offers little benefit acoustically. The primary reason for multiple pane glazing is for thermal reasons.

This is hard for people to understand the reasons why without some acoustic knowledge. But in a vague nutshell, a pane of glass will have a dip in the performance at particular frequencies (resonances caused by bending waves across the glass). Therefore a standard 4 mm glass / 6-20 mm gap / 4 mm glass double glazing will get that dip in the performance twice, thus making performance worse at these frequencies.

This is why to increase the performance of double glazing you need the two panes to be of different thickness. Mass is also important, and a laminated glass will help.

See the data sheet for Pilkingtons Optiphon (found with quick google search).

The document on their site contains test data highlighting the improvements in performance.

The 9.1mm laminated glass / 20 mm gap / 13.1 mm laminated glass provides the best acoustic performance, and is about as good as you get with a double glazed unit.

If this is not good enough, or low frequency noise is a problem, a secondly glazed unit is necessary and provides by far the best improvement (even if you where to maintain existing Windows). As well as being the most effective solution, this can also be the cheapest solution!

Secondary glazing only needs to consist of a single pane (spec. dependant on consultants advice), but the gap between existing/new double glazing and the secondary pane needs to be min. 100 mm, increasing gap will increase performance. There is no difference in performance increasing your the small gap between double glazing, this gap needs to be large to get the performance hence why we need a secondary unit.

I hope the above helps shed a little light on the subject and that I have highlighted the risks of just picking any old specification. Seaking proffessinal advice from an acoustic consultant is the best way to ensure you get the results you want, and may even save you a penny or two on paying for inappropriate glazing.

Good luck guys.

dominoman

Please come back once it's done and let us know how you get on.

I have single glazing near busy road and rail junction so interested to hear what difference it makes.

sharpting

Hi

I'm trying to reduce traffic noise in my bedroom and living room. I've been quoted double glazed 6.8 Stadip laminated and 6mm toughened for the other pane. But I've read that the difference in thickness between the two panes should be at least 30% so this concerns me. My question is:

Which is better, 6.8mm + 6mm or 6.8mm + 4mm?

and from the answer to the above. If I can afford it, would 6.8mm and 10mm be better or would the reduction in the gap cause an issue?

Thanks a lot

Darren