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Installing new windows can reduce noise pollution by up to 50%. But the amount of noise reduction you can expect depends on many factors. These include build and material quality, number of panes, and the way they’re fitted. For best results, look for high-quality acoustic windows.
In this article, I’ll cover the main factors to look for when choosing new windows. I’ll also offer some suggestions for how to improve your existing windows if a full replacement is beyond your budget.
You can also check out my guide on soundproofing windows.
How Do Windows Transmit Noise?
Glass, as a material, has fairly good soundproofing properties. This is because:
- Its smooth surface is better for reflecting sound waves
- It’s fairly hard, and so can diffuse sound waves
- It doesn’t have a crystalline structure, so vibrates less when sound waves make contact with it
However, the biggest drawback of glass in a home setting is that it’s much thinner than the surrounding walls. This means it can’t exhibit these properties, which is why it’s often the weakest area of the room.
Another issue is that glass has a resonant frequency within a human’s hearing range. This means that when sound waves come into contact with glass, they cause it to vibrate. However, the point at which this happens is determined by the material’s thickness.
Also, glass is very rigid. Sound waves are most effectively blocked by limp mass, which simply doesn’t vibrate when sound waves come into contact with the surface. A good example is mass loaded vinyl.
So the rigidity of glass means that it can vibrate more easily than other materials. This is also impacted by its mass, as panes of glass need to be thin for them to be transparent.
If this wasn’t a factor, thick panes of glass would be much more effective at blocking sound.
Single-glazed windows are definitely the worst for noise pollution. This is because they’re thin (meaning they’re also bad at heat insulation). It’s also because they can transmit sound waves more easily through vibrations.
Double-glazed windows, on the other hand, have a gas-filled gap between the two panes. Alternatively, this will be a complete vacuum, but this isn’t always the case.
The void between the two panes helps to dampen sound waves by creating dead space. Sound waves can’t pass through this dead space as effectively, and so they’re reduced before they make it into the room.
In short, windows will always be the weakest area of a room because we’re limited by the need for them to be transparent.
If this weren’t the case, thick panes of glass would be very effective at blocking sounds. But if we couldn’t see through them then there wouldn’t be any point in having them anyway!
What To Look For While Buying New Noise-Reducing Windows
If you’re buying new windows mainly for noise reduction then there are a few things to look out for. Most sound-reducing windows are also effective at thermal insulation, which is always a bonus.
Some companies sell windows marketed as acoustic windows. These are quite expensive but do get the job done. You should look out for the following factors when buying any new windows, acoustic or otherwise.
1. Number of panes
As mentioned, single-glazed windows aren’t worth considering. In fact, it’s unlikely you’ll be able to find a company in this day and age that still sells them.
You should look for either double-glazed or triple-glazed windows if you want any level of noise reduction. As a minimum you’ll want to get double-glazed windows.
Triple glazing is exactly the same premise, just with another pane of glass sandwiched between the two. It will make a difference to noise reduction, but the difference will be much less noticeable if you already have double-glazed windows.
What’s more, triple-glazed windows can cost up to 50% more than a double-glazed equivalent. For many, this price increase isn’t offset by the improvement in noise reduction and thermal insulation.
2. Vacuum spacing
Double-glazed windows have a gap between the two panes, which is usually filled with gas. Typically this is argon, which is a much poorer conductor of heat than normal air. As a result, it keeps warm air in the house and cool air outside.
But if you’re looking specifically for noise-reducing windows, look for ones with a vacuum space between the panes. Sound can’t travel inside a vacuum, which makes them great for soundproofing.
The biggest drawback is that this is expensive and often impractical. Also, once a gap appears in the seal (either with age or the house settling), you’ve lost your vacuum. This will have a big impact on its noise reduction.
3. Laminated glass
Laminated glass is simply a pane (or two) of glass stuck together. If it’s not made of 2 panes of glass, then it can be a pane of glass and a sheet of plastic or acrylic.
The main advantage is that it’s a much tougher material. But it’s also more dense and has more mass, meaning it’s harder for sound waves to pass through.
One material that’s commonly used is polyvinyl butyral (PVB). This is a resin best known for its clarity, flexibility, and strength. This makes it a perfect addition to acoustic windows because it massively improves noise reduction.
4. Rubber spacers
All double-glazed windows contain spacers. These are the part that sits between the 2 panes of glass to hold them apart, hence the name. They can be made from all kinds of material, but the most common is plastic.
Having rubber spacers instead helps to reduce vibrations passing through the window. Unlike plastic, rubber is much more flexible and so won’t pass on sound waves as easily.
What’s more, they’ll create a barrier between the window and the surrounding frame, essentially acting as decouplers. This prevents sound transmission between the window and the building’s frame.
Are Soundproof Windows Worth It?
If you’re thinking of installing dedicated soundproof windows, expect to rack up a bill of several thousand dollars. All of this technology comes at a price, and it’s definitely not cheap.
Using glass laminated with PVB can offer a 50% noise reduction on traditional glass windows. When you factor in all the other components mentioned above, you’ll end up with fairly soundproof windows.
Whether soundproof windows are right for you will depend on your budget, the type of windows you already have, and how annoying you find noise pollution.
If you’ve already got double-glazed windows then you’ll only really notice an improvement by using laminated glass. If you can’t source laminated glass, then there won’t be much point in fitting new windows.
How To Reduce Noise From Your Existing Windows
Perhaps new windows are a bit outside your budget, yet you still want to reduce levels of noise pollution.
Try some of the following tips for reducing noise pollution in your home. While these won’t be as effective as soundproof windows, they should offer you some results.
1. Seal any gaps
The first place to start is sealing any gaps around the windows. Not only can sound pass through these small gaps, but a window that doesn’t sit properly in its frame can vibrate more easily.
The best product to use is acoustic caulk (Amazon). It converts sound energy into heat, and is flexible so will move with the structure.
Follow this video on how to replace window caulk for best results.
2. Add magnetic secondary glazing
Magnetic secondary glazing is an effective way of adding mass to your windows without completely replacing them.
You fit a new frame in front of the existing one and then attach acrylic panes with (you guessed it) magnets. You can buy kits online and don’t need much in the way of DIY skill to install them.
3. Fit noise reducing curtains
Noise reducing curtains (my top picks) have much more mass than normal curtains. Granted, they’re not the most effective solution, but they will do something.
Try to find the thickest curtains possible, as this will help to dampen noise pollution coming through the window.
If you can’t find any that are thick enough, consider sewing a set of curtains together. This will double the thickness and should make more of a difference.
Of course, ensure the curtains cover as much of the window as possible. You’ll want the curtains to extend over the top, bottom, and sides of the window pane.
Some Final Thoughts
It’s perfectly possible that new windows can reduce noise pollution. However, their effectiveness will depend on what you buy and how it compares to your current windows.
If you can afford them, soundproof windows will be your best bet. As these are expensive, you might be better upgrading the quality of your double-glazing, or trying one of the less invasive options listed above.
After all, fitting new windows can be expensive and time-consuming.