A tinted film is applied to selected windows to darken or shift the color. Professional installation is recommended as do-it yourself may have poor results. Most states have various laws on tinting. For example, California’s requirements are:
- The windshield and front driver’s side and passenger’s side windows cannot receive any aftermarket tinting.
- If the rear window of a vehicle is tinted, the vehicle must have outside rearview mirrors on both sides.
Keep in mind that tinting may make it more difficult to see at night and while in the sun, it may increase the air-conditioning load in the summer (but reduce the heating load in the Winter). Film applied to the long slope of the rear window may also add distortion.
I had all the side windows and the rear window of my S85 filmed. The fronts are filmed to allow 70% of visible light to pass, which is the California limit. The rears and the hatch window I had filmed to allow only 40% of visible light to pass. What was once a heat load problem with my car is now cool and comfortable. Note that I experienced no distortion on any window; I did not have filming added to the windshield. Cost = $600 here in San Jose.