DIY Secondary Glazing: Suitable for Noise Reduction?

diy secondary glazing

Last updated: February 9, 2022 at 12:26 pm

If you’re experiencing noise problems in your home, you may have read that windows are one of the biggest weak points. It’s true that windows let in a lot of noise, particularly if they are in poor condition or are only single glazed. Of course, the best solution is to replace the windows with good-quality double glazed ones.

But what if you can’t afford them?

There are DIY secondary glazing kits available, most commonly in two variations;

  • insulating film
  • magnetic panels

But will they be effective or just a waste of money? Can they keep out the noise and keep in the heat as well as professionally fitted ones can? Let’s investigate.

Insulating Film Secondary Glazing

insulated film glazing kit

Insulating film is the cheapest and easiest type of secondary glazing to fit. You simply stick a sheet of the film directly onto the glass of your existing window. Then, using a hairdryer to warm the film, the creases and folds will disappear and attached tightly to your window.

The trickiest part of insulating film is cutting is to the exact size of your window.

Stormguard 11SR0666SQM 6Sq m Secondary Glazing Window Insulation Film
  • creates a secondary glazing effect on windows to prevent draughts and...
  • includes self-adhesive fixing tape

Last update on 2023-11-21 at 14:11 / Images from Amazon Product Advertising API


Insulating film works well if you want to keep heat within your home or prevent condensation from forming on your windows. It forms a cushion of air that insulates and adds an element of moisture prevention.

The other advantages are that it’s very cheap and if you take your time, it’s very easy to fit.


Although it counts as secondary glazing, this product is not suitable for use in soundproofing projects. It is a thin piece of film which provides almost no additional mass to your window. As greater mass equals greater soundproofing, a thin piece of film is going to make no practical difference.

It also does nothing to block any gaps or holes in the frame or between the frame and the wall allowing sound to continue to enter.

The final disadvantage is that the film is only designed for temporary use. You could expect it to last for one or two seasons before you would need to replace it.

How Much Does It Cost?

You can buy a 3m x 1.5m roll of insulating film online for around £9-£10.

How Effective Is It?

A good quality insulating film will make a real difference in keeping the heat in your home. However, if you plan to use it for soundproofing, it will not make much difference as the film is so thin.

Magnetic Glazing Kit

magnetic glazing kit

A magnetic kit includes a plastic glazing panel which are then attached to the existing window using magnets. There are also kits available that use adhesive strips and even ones you must screw in.


Plastic is a good choice for glazing as it not only helps block sound but will also help keep heat in the room. Plastic does not conduct heat well, so it will be harder for heat to escape from your home.

The new pane will enhance this effect by forming a tight seal to block air from any gaps or holes in the existing window. You can boost the effect even further by using soundproof caulk and acoustic sealant to seal these gaps before you fit the secondary glazing.

Another advantage of secondary glazing over double glazing is that it decouples the window panes. Although double glazing has two panes, because they are linked by the frame, they act as one unit. So, if the noise is caused by strong vibrations, such as that caused by lorries driving past, then they will both vibrate together. This makes soundproofing less effective. Because the secondary glazing is separate from your original window, it stops more of the vibration.


One minor side effect is that a lot of heat can build up in the gap between the pane and the secondary glazing on a sunny day. If the temperature gets too high, it could damage the plastic. As the pane is only held on by magnets, it may be worth removing it on a very hot day.

The second disadvantage is that if you use adhesive tape, it can become less effective over time and need to be replaced.

Some people find secondary glazing unattractive. For example, if you live in a period property with original windows, you might find you hate how the additional pane looks in your room.

Finally, there is a limit to how much sound the extra pane can absorb or block. If you have windows that are in very poor condition, this would be a temporary improvement at best. Eventually, you will need to replace the old windows for heat, noise, and safety reasons. So, before you buy secondary glazing, get a professional in to assess how much life the windows have left.

How Thick Are the Panes?

Most kits come in a range of thicknesses, and generally, for soundproofing purposes, the thicker, the better. A minimum of 3-4mm thick is recommended. The greater the mass, the more the sound wave’s power will bleed away while passing through it. Depending on the kit you buy, the panes can either be acrylic or glass.

How Much Does It Cost?

The cost will depend on how thick a pane you choose, how big the window is and how many windows you want to cover. As a rough guide, you can get a one-metre square, 3mm thick kit for between £55-£65. Shop around and read reviews to ensure you get a good price and a quality product.

How Effective Is It?

The big question is, how much noise will this type of glazing block? Depending on the brand you choose, a DIY secondary glazing kit can reduce sound penetration by around 50-65%. This should make a significant difference to all but the loudest environments. These kits will make the biggest difference on single glazed windows.

Merriway BH04945 StormSeal Window Insulation Secondary Double Glazing...
  • Pack of 1 x Window Insulation Kit 1.2 Metre x 1.5 Metre (1.8 Sq....
  • Provides Secondary Glazing Style Draught Exclusion

Last update on 2023-11-21 at 14:11 / Images from Amazon Product Advertising API

Alternatives/Complements to Secondary Glazing

The key in any window soundproofing project is to seal up all gaps. Even small holes can let a surprising amount of noise through and disturb your peace. Here are some ideas for things you can do to either enhance the effect of the secondary glazing or not use it altogether.

Acoustic Caulk/Sealant

As explained above, the soundproofing effect of the secondary glazing will be more noticeable if you seal up any gaps or holes in your existing window. You should check for gaps between the panes and the frame, holes in the frame itself and gaps between the frame and the wall. A specially manufactured acoustic sealant will do this job best. It’s not a solution on its own, but it is an important part of the process.

Soundproof Blinds

Soundproof blinds come in two types. The first is a honeycomb design that provides air pockets that stop sound from getting through. The second looks like a normal roller blind but has a layer of soundproofing material in the middle. Either type will reduce the sound you can hear by around 30%. If you only need to block low levels of noise, this may be enough; otherwise, you can pair it with the secondary glazing.

Soundproof/Thick Curtains

Soundproof curtains will block sound, light, and keep the heat in your home. If you need to block a lot of sound, then you may want to but soundproof curtains. If not, then thick curtains may do the trick. Again, you can add them on their own and see if they work, but as the cost would be similar to secondary glazing, you may want to try the glazing first. If you already have thick curtains for can get some on sale or at a charity shop, then it would be better to try them first.


If you live in a noisy area and cannot afford to replace your windows, a DIY secondary glazing kit may be a good solution. A magnetic kit is significantly less expensive than even getting new panes in your existing windows instead of replacing them entirely.

There are many brands available with different sizes and thicknesses, so make sure you do your research to choose the one that is right for you.

If you find secondary glazing unsightly, some of the other options listed at the end of the article may provide a workable alternative, although they may not be as effective as secondary glazing. If you can afford it, a good quality secondary glazing kit combined with thick curtains should reduce the sound entering your home to barely audible at most.

Choose the options that are suitable for your needs and within budget, and you can make a substantial improvement to the noise you can hear and restore peace and quiet to your home.

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About the Author: AJ

AJ is a self-confessed soundproofing nut. He has written full-time on Quiet Living for the past 4 years, and has a wealth of knowledge about living a quieter life, soundproofing and fixing loud noises.

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