As we discussed in Part 1, window film is a very versatile product that can solve a great many glass related problems. Even with that being true, there are some things window film simply can’t fix. Here they are.

Window Film and Night Privacy

Many customers want a window that you can see through during the day, but can give you privacy at night, even with the lights on. This is one of the most common customer requests. Unfortunately, there is no film that is transparent (see-through) during the day and at the same time blocks the view from the outside at night when you have the light on inside.

All glass windows reflect a certain amount of light, the percentage depends on the glass. Usually, the higher the efficiency of the window, the more light it reflects. During a very bright day, a passerby would probably not be able to see through a high-efficiency window into your home. This is because the amount of light being reflected is greater than the amount of light coming out of your house. 

The same principle applies at night when you are inside your home. If you try to look through your window at night in a brightly lit room, you would probably see your own reflection. This is because the amount of light being reflected is greater than the amount of light coming from the outside. Furthermore, since a window only reflects a percentage of visible light, the light that is not being reflected is going through the window and into the dark street. This, of course, would enable any passerby to see through your window.

Window Film and Drafty Windows

Many times customers contact us because they have windows that are acting as poor insulators. The common complaint is they can feel drafts coming from their windows or they have windows that get condensation.

Drafty windows can be caused by a variety of issues, sometimes in combination with each other. Loose, rotting window frames or a broken window sash are often to blame for these issues. Window film will not solve these problems. You will need to have your windows replaced by a competent carpenter or professional window technician.

Related Articles: Five Common Window Problems and How to Resolve Them

Is Window Film Bulletproof?

No window film will make your windows bulletproof. You should not believe any marketing information telling you it is.

We have seen some companies try to market bulletproof window films. While they do have some testing, specific details, especially the type of glass they use, need to be revealed to understand their results.

Based on our research, we don’t feel that the testing we’ve seen is consistent with reality. Hence, we are unable to recommend any window film products that claim to be bulletproof.

Will Window Film Stop Windows From Breaking?

Films like 3M Safety Window Films are strong and durable, but they will not prevent glass from breaking. Instead, it is designed to hold together, not shatter into fragments. This can potentially delay an intruder from entering quickly and, in some cases, cause them to reconsider and move on. It’s also important to understand that even if the filmed glass can remain intact as an intruder is attempting to enter, the window’s framing system may not be able to hold together (which means there would be less of an intrusion-delay benefit).