Important things to be aware of when tinting your car windows
Tinting your cars windows is an easy solution to lower the temperature in your car, as well as reducing the UV-rays affecting your cars window screen. What you should be aware of, however, when you want to get the windows in your car tinted, is that it's surrounded by laws that need to be followed in order for you to operate your vehicle safely. You could also be punished for not obeying these laws. Therefore, it's very important that you're aware of what to do to follow these laws before going ahead with car window tinting.
The first thing you need to know is what VLT is. VLT stands for Visible Light Transmittance and is the measurement used to tell how much light the tinting or the overlay is allowed to block out. The lower the VLT, the darker it is inside the car. 35% VLT is the darkest shade of tint you can have in all of the windows in your car except the windshield. 35% VLT should be low enough to keep your car substantially cooler, even if you live in a very warm area.
The windshield is the most important window in the car, and it's of vital importance the driver can see as clearly as possible through it. This is why it's not legal to use any type of overlays or tints that extend further than the bottom of the sun visor, or bottom of the stone guard on trucks and buses. The normal VLT of a windscreen is usually around 85%, and a windshield shouldn't have a VLT much lower than that. It's acceptable to use a clear windshield protector, as long as it doesn't lower the VLT further than 70%.
Knowing the VLT
Usually tinting products and overlays come with indicators on how much VLT they allow. If you want to be absolutely certain that your car performs up to legal standard, you should take your car to the shop, where they can help you with measuring the VLT through the different windows with a VLT meter. Most mechanics and window fitters have these. It might be a good idea to do this as it is hard to determine the VLT of your windows in their natural states. If a window has a VLT of 70% in its natural state, than applying an overlay that are equipped to offer a 35% VLT to a window with 85% VLT will make the overall VLT much lower and thus push you under the line of what's legal to have in your car.