It's a reasonable question given some films contain metal layers. The honest answer: the great majority of window films have no meaningful effect on phone or Wi-Fi signal — and where there could be an effect, we can specify a non-metallic film.
Which films could affect signal
Only heavily metallised (reflective) films have the potential to attenuate signal, because metal can interfere with radio waves. Even then the effect is usually small, and signal mostly enters through walls, doors and other windows too.
Ceramic and non-metallic films don't
Spectrally-selective ceramic films and dyed/UV films are non-metallic, so they don't affect phone or Wi-Fi signal at all — while still rejecting heat and blocking UV. If signal is a concern, we simply specify a ceramic film.
In practice
For homes and most offices this is rarely an issue. If you're sensitive about signal (or have a lot of metallised glazing already), tell us on the survey and we'll choose a film that leaves your signal untouched.
The bottom line
Most window film doesn't affect phone or Wi-Fi signal, and where it might, a ceramic (non-metallic) film avoids it entirely. Book a survey and we'll spec accordingly.
Thinking about window film? We offer a site survey anywhere in Scotland, with most quotes returned within 24 hours.