A common misconception with the purchase of a new car is that the “tinted” windows will provide you and your car’s interior from damaging UV rays.
“privacy glass ” will not provide you with UV protection or even heat rejection.
This glass is typically dyed glass and provides only privacy. Solar glass is a step up from the clear automotive glass and has visible light transmission (VLT) varying from as low as the federal limit of 70% VLT up to 88% VLT (which is clear auto glass). Most automotive solar glass ranges 74-84% these days with UV rejection not much over 40% unless it is factory privacy glass, which has UV rejection as high as the 60 percentile range. Some cars, trucks and sport utility vehicles, in particular, come from the manufacturer with glass that has been darkened using an electrical process called “deep dipping”. This “factory tinted” glass is a dark shade but does not protect the interior of your car from the sun’s heat or damaging UV rays as well as aftermarket window tinting. Major film manufacturers have formulated tinting materials to closely match the factory tinted glass allowing the front door windows of some truck and SUVs have window tint with a legal matching shade. It is also possible to apply aftermarket window tinting over factory tinted glass to make the windows darker and to improve performance.
In other words, “factory tint” means the dye is actually in the glass, it can never be removed. “Aftermarket tint” is a transparent paper with an adhesive side that bonds to the glass, it can be removed.
“When you apply a low visible light transmitted [or VLT] film to an already dark window, such as on an SUV, you’re creating not only the privacy effect, but you’re giving yourself all of the benefits of the thermal barrier for heat rejection and heat absorption, “says Tony Scire of 3M Auto Care Market Center. “It’s very important to understand that eve
n though the glass looks dark coming out of the factory, there are no thermal performance characteristics in the glass.”
Josh Buis of Window Film Operations for Scorpion Window Films agrees that while factory glass may look similar to windows that have aftermarket films installed on them, the performance is rarely up to par with the aftermarket.
“There are many vehicle manufacturers that provide tinted windows from the factory, but this is nothing more than privacy glass and offers to vary little protection from the sun and all of its damaging properties,” he says. “The addition of a light VLT film over your OEM privacy glass will increase the protection on the interior in the rear of your vehicle.”
All of which is to say that when it comes to protection, most OEM window treatments are generally focused only on aesthetics, not performance. That becomes a key selling point for restylers as they educate their customers.
Aftermarket films, however, provide a host of other benefits beyond mere appearance, says Ari Sacal of Solar Gard.
“In North America, 90% of side and rear car windows manufactured today offer very minimal protection from UVA rays,” Sacal says, noting that aftermarket films can block up to 99% of UVA and UVB. “[Aftermarket products shield] passengers against premature aging and skin cancer, and discoloration or fading of leather, vinyl, and fabric … and protect a customer’s investment in their vehicle by protecting passengers and the vehicle interior from UV rays, enhancing passenger comfort and customizing the vehicles aesthetic appearance. This shield protects the passenger’s skin from the sun’s damaging rays, regardless of the film darkness.
“Window films also reject solar energy, decreasing a vehicle’s interior temperature, reducing the need for air conditioning and cutting glare,” he adds.