Window breakage due to the use of window film?

What should you consider when applying window film to your window to prevent thermal breakage? When applying film to windows of houses or cars, for example, there are many uncertainties about window breakage. Would a window film have an impact on the window? Below you will find useful information that will make everything clear.

Does window film cause thermal breakage?

When the Netherlands started using double glazing in the 1970s, window film experts and the glass industry actually made many mistakes. This was caused by a lack of knowledge, but now we do have that knowledge. Unfortunately, we still suffer from this. When a house is delivered, it is often said, 'do not place window film because then the windows will crack.' This is not true!
Look around you and you will see all kinds of window film everywhere. Applied to all types of glass. Both indoors and outdoors.
Can you just stick everything everywhere? No, not quite. There are indeed things you need to take into account. With the right knowledge, you can prevent a lot.

What is thermal window breakage?

When glass gets cold or warm, it will expand differently in the frame. When the entire glass expands evenly, this is not a problem and very little can happen, unless the window really gets too hot or there is already a break in the window. Sometimes one part of the window becomes warmer and the other part does not. This creates certain tensions that can lead to thermal window breakage. The window can withstand a temperature difference of 30 degrees Celsius without any damage being caused. The break that can occur consists of a single fracture line that starts at the edge of the glass and develops further. Thermal breaks are clearly recognizable by 2 clear parameters.
- Entry in a right angle
- Passage in a right angle.

A large number of different causes can lay the foundation for the emergence of large temperature differences. Here is a list of the most common causes.


Partial shade / shadow  Trees, coverings that partially shine on a window

Interior sun protection, blackout Too close to or partially covering window, causing difference on window

Painting, sticking, posters Especially when using dark colors that attract more heat. Posters, advertisements, film, stickers

Heating Placed too close to window

Local heating Defrosters, welding machines, exhaust, blowers

Dark objects
directly on glass
Decorations, furniture, pianos, black curtains

Wide rebate From approximately 30mm, e.g., in roof glazing or highly insulating windows

Thunderstorms Summer days with hard temperature fluctuations

Applying mastic Continuous glass constructions reaching to the ground and uneven protective covering

Which glass is suitable for applying film?

Thermal breakage can potentially occur in any type of glass. Applying film to a window increases the chance of this happening if you do not take certain factors into account.

With single glazing and double glazing, the risk is lowest and window film can be applied to both the inside and outside of a window. These types of glass are flat and smooth, making them suitable for application. Patterned glass is a type that cannot be applied, due to the textured surface on the glass. When using HR++ glass, it is not recommended to apply film to the inside of the window because there is a certain coating on the inside of the glass. If you do this anyway, the window may not be able to dissipate its heat optimally, which can lead to thermal breakage more quickly.

Applying film on the inside or outside of the window?

Applying film to a window prevents the window from dissipating its heat well. When the window film is on the inside of the window, there is a greater risk of thermal breakage because the window film could absorb too much heat. If a lot of sunlight falls on your window, it is advised to apply the film on the outside because the window can dissipate its heat more easily. With single glazing, double glazing, and Plexiglas, losing heat is not a problem because it automatically drives the heat to the outside and does not become too hot. Applying film to the outside of the window has the same principle as applying it to the inside, but the advantage is that it can more easily dissipate its heat to the environment. So applying film on the outside is more often applicable, but applying it on the inside of a window is also certainly feasible! Many of our films can be mounted both indoors and outdoors. You can then choose the indoor or outdoor variant of the film on the product page. If this option is not available, please inquire by phone or via email whether outdoor installation is possible for the film you have chosen. Not all variants are standard on our webshop, but you can simply request a quote for them from us.

Do I have insurance against thermal breakage?

No, regardless of the insurance you have, when using window film on a window, the insurance against any glass damage is void. If you have doubts about using window film on your window, you can always visit Dr. Sticker or contact us by phone/email. In all cases, installation of our films is entirely at your own risk.

No doubts?

Then order your window film easily through our webshop. If you prefer to order a film or sticker with a print, easily order through our online design tool or request a non-binding quote from us: