Did you know the factory installed tint on the rear windows of SUV s and mini vans was designed for privacy, not solar protection? Many people know that adding window tint to a vehicle can add style while significantly reducing heat and glare, but they stop short when it comes to adding tint over privacy glass. It's a common misconception that factory tinted rear windows provide full solar protection. Adding window tint to factory tinted glass can improve the solar performance of the glass by 50% and help block more than 99% of harmful UV rays.