Window films have become a constant in automobiles since their development, with different innovations being made more effective every year. There’s a variety of reasons people get tinted windows. These include privacy and heat control, but do you actually know how these films work?
It’s not surprising. In Phoenix, for example, auto window tinting is so common that it’s easy to get the type of window film you want to be installed with speed and efficiency. But the science behind these films is quite interesting once you start discovering how they work.
First of All, They’re Not Just Film
You may think of auto tinting as taking a piece of plastic and applying it to the windows of your car. You’re only half right. The substance that makes up auto tinting is actually a multi-layered coating made up of polyethylene terephthalate (PET), a resin that’s best known for how easily it can accept multiple coating of several compound mixtures.
These mixes can be made up of different materials, such as high-tech nanoparticles and the good old-fashioned ceramic components. But for cars, the two most common uses for window film are to reduce the heat inside the car and prevent people from easily seeing what’s inside.
Light is Heat
First of all, those two functions work in tandem, as the majority of things that do heat up a car’s interior such as infrared and ultraviolet rays are also present in many things that allow people to peek inside vehicles (in this case, the sun.) Blocking out light is the best way to block out heat, but auto tints are far more sophisticated than just putting a cloth blanket over your windows.
When UV and infrared light hit a tinted car window, the metal and dye components activate to convert this solar radiation into infrared radiation, which another layer of the film repels from the outside. This allows your car to still keep enough heat inside it while keeping excess heat from the outside away.
Different materials can do this with varying rates of effectiveness, but it’s generally accepted that a ceramic coating can reduce the amount of heat that gets into your car by almost 80%. They’re also a little more expensive than your regular car film, but the price adjustment will be well worth it.
The Right Level of Privacy
As for the tinting that makes it more difficult for people to look inside the vehicle, there are two ways that an auto tint can accomplish this without severely limiting visibility from the inside.
The first is called a mirror-coating film. Through careful application of a mirrored coating to the final layer of the auto film, you can achieve a surface that functions like a one-way mirror, where anyone peering inside the vehicle can only see a reflection of themselves. This is usually applied to government and federal vehicles, so search your state’s tinting and sticker laws to avoid penalties.
The more common type of tint is the privacy film. It makes the windows translucent instead of transparent, perhaps being frosted for additional insulation and privacy. These types of window tints come in varying shades of darkness, which are usually coated with some metal dye for their refraction properties.
