Home → Windows → Windows FAQs → How do windows reduce noise?

Noise is a constant annoyance for many people living in crowded locations, near a busy road or under a commercial flight path. Whether you’re experiencing low-level background noise that’s disrupting your sleep or occasional bursts of loud noises, you’ll benefit from windows with good noise reduction capabilities.

All windows reduce noise to an extent, but some are much better than others. State of the art acoustic glass will cut out much more noise than a single pane of glass rattling around in an old frame. But what is it that makes a window better or worse at reducing noise? Read on to find out.

How sound works

Before we go any further, we need a working understanding of what sound actually is. Sound is transmitted in pressure waves, which are a little like water waves, except they move through the air. The source of any noise will cause air molecules to vibrate, creating a knock-on effect of vibrating molecules all the way to a recipient, like a human ear or a microphone.

Sound waves have two important properties for us to be aware of: frequency (pitch) and volume. If a sound has a higher frequency (measured in Hertz, Hz), it means that the waves are travelling closer together and the sound is a higher pitch. If a sound has a higher volume (measured in decibels, db), it means that the distance between each peak and trough (the highest and lowest points of the waves) is greater.

It is often the volume of different sounds that cause problems for people when they’re trying to live, work and sleep, but the frequency of the offending sound is actually more important to pin down from a noise reduction perspective. This is because glass doesn’t reduce the volume of different frequencies equally. The focus should be on catching as many frequencies as possible, rather than tackling a general volume level.

The noise reduction effects of regular windows

Regular windows are able to cut out some noise simply by providing a barrier between the inside and the outside. As a material, glass is very inflexible, which means it’s naturally quite good at cutting out sound. However, the glass used in windows is relatively thin, which reduces its effectiveness. This is why single glazed windows are particularly poor at noise reduction.

Double and triple glazed windows are better at cutting noise levels because there’s more for the sound to get through before it reaches your ears. In these cases, there will be at least another pane of glass and a layer of air or gas (normally argon) for the sound wave to travel through.

Using noise-reducing designs

However, if the two panes of glass are the same thickness, they will have the same strengths and weaknesses. All panes of glass have frequencies at which they’re particularly good at blocking sound and others at which they’re particularly bad.

This means that it’s not necessarily ideal to install two equally thick slabs of glass of equal and be done with it. In fact, it’s better if one pane is slightly thicker than the other, as the two panes will then be better at cutting out different frequencies.

These windows are known variously as acoustic windows, noise reduction windows or soundproof windows. All of them work on the same principle of using glass panes of varied thicknesses to cut out as many frequencies of sound as they can. It is also possible to get windows specially designed to cut out the particular frequencies that your home experiences.

Other ways to reduce sound

Varying glass thickness is not the only way that windows can reduce noise, though it’s one of the most effective. However, there are other methods that can be employed. One is simply increasing the thickness of the glass panes. As we’ve already noted, this isn’t as effective as varying their thickness.

Another method is to change the gap between the panes (assuming the window is double glazed). However, the gap needs to be about 60mm before it makes a noticeable difference, which isn’t practical for many installations.

In addition, it’s possible to change the gas used between the panes, as both air and argon have a negligible impact on noise reduction. The use of Krypton or other heavy gases can slightly reduce noise levels, but not by enough to justify the cost.

The one other method that is worth looking into is adding noise reducing laminate to the glass. This further enhances the ability of the glass to catch and reduce volume from different frequencies without drastically changing the design of the units.

Tips to make rooms quieter

If acoustic glass or one of the other noise reduction methods seems like a step too far at this stage, there are other ways that you can reduce noise in your home that don’t have to cost much.

A lot of noise could be getting in through gaps around the windows or other entrances into the room. Stopping these gaps will reduce noise and also increase the room’s thermal efficiency as an added bonus.

In addition to stopping the gaps, the more fabric and plants you have in a room the more sound will be absorbed before it hits your ears. Heavy curtains, rugs, soft furnishings and house plants will all make a difference.

For the best long-term improvements, however, you need to install the right windows. Contact KLG Rutland to find out more.