Is the Front Windshield Film Applied on the Inside or Outside?
3 Answers
The front windshield film is applied on the inside. Applying it on the outside would expose it to wind and sun, significantly reducing its lifespan. Applying it on the inside provides better protection and, in case of an accident, helps hold shattered glass together, preventing injuries to passengers from flying glass. If applied on the outside, broken windshield glass could pose a risk to the driver and passengers, failing to serve its anti-shatter purpose. Car window film is a thin layer applied to the front and rear windshields, side windows, and sunroof. This film, also known as solar film or anti-shatter heat insulation film, primarily blocks UV rays, reduces heat, and prevents injuries from sudden glass breakage. Additionally, its one-way visibility feature helps protect personal privacy.
I used to think about this issue too, and later I asked a professional tinting shop to understand that the front windshield film must be applied on the inside. If it's applied on the outside, the wipers will ruin it when they swipe, and road debris like stones and sand will definitely scratch it when they hit directly. Applying it on the inside avoids these problems, and dust has much less impact. However, special attention must be paid to cleaning during the application—the inside of the glass needs to be repeatedly scraped clean with a squeegee, leaving no dust at all, or bubbles will ruin the entire effect. We tinting shops rely on this skill to make a living, and even the triangular area near the rearview mirror must be carefully cut out, otherwise, the car inspection will be problematic. It's recommended to choose a film with a light transmittance of over 80% for safer nighttime driving.
Last time I got my car's film replaced, the technician said the windshield film must be applied on the inside - doing it on the outside just doesn't work. If installed externally, the wipers would scratch the film during rain, and highway driving could cause insect impacts to crack it. Applying it internally avoids these issues and makes the film last several years longer. However, the installation process is quite meticulous - the technician first sprays soapy water on the glass for lubrication, carefully aligns the film, then slowly smoothes it out. They specifically warned me not to roll down windows for three days afterward, otherwise the edges might peel. What I appreciate most now is how my arms don't get sunburned in summer - the factory-installed film has excellent UV protection, even keeping the steering wheel comfortably cool to touch.
