Solar energy reaching a car is made up of visible light, ultraviolet and infrared, and infrared is a significant part you cannot see. Nano-ceramic film is designed to act on that energy at the glass, so less of it enters the cabin in the first place. The practical result is a car that is more comfortable in the sun, with less glare and less UV falling on the interior. Performance varies by film and shade, so compare the specifications for the option you are considering and talk it through with the dealer handling your enquiry.