When it comes to tinting your car windows there’s one important and commonly asked question: how high should you go? You may already know tinting film darkness is measured in VLT (Visible Light Transmission). VLT numbers represent the percentage of light that comes through the windows.
U.S. laws typically define it as following:
“Light transmission” means the ratio of the amount of total light, expressed in percentages, that is allowed to pass through the sunscreening or transparent material to the amount of total light falling on the motor vehicle window.
“Luminous reflectance” means the ratio of the amount of total light, expressed in percentages, that is reflected outward by the sunscreening or transparent material to the amount of total light falling on the motor vehicle window.
For example, 40% VLT window film would block 60% of light through the window and allow 40% to pass through. In a majority of cases you do not need more than 50% VLT for the tint to be very effective, despite what many people believe.
The image below is an example tint darkness chart. It shows the effectiveness and comparison of various levels of tint and should help you visualize how your car tint film may appear:
As you can see going for anything below 50% VLT could definitely be considered too much. Even higher light transmission percentage can be effective in blocking the sun and reducing visibility from outside.
Most common VLT used in cars today is 70%-85%. For majority of drivers that is more than enough to reduce glare from the sun and block most harmful UV rays. Even installing 85% VLT tinting film can make a huge difference when driving.
You also don’t want to go overboard with tinting percentages. Tint film under 50% VLT can make it very difficult to drive in low light conditions such as tunnels. Poor weather or driving at night can be especially difficult with low VLT. Many new vehicles already come with pre-tinted windows of 70% VLT which is something many vehicle owners are unaware of.
You are no doubt aware how distracting the sun’s glare can be if you live near the beach or frequently drive in snow. Nevertheless, you will not be driving under these conditions all the time. Therefore you should be reasonable when choosing your darkness levels. Although there are more benefits to tinting windows than reducing sun glare, you can always keep sunglasses in your glove box and use them when needed. Unlike window tint they are far easier to take off when not needed.
Most importantly, ensure that your window tint percentage is within legal limits in your state.