Solar energy reaching your windows arrives as visible light, ultraviolet and infrared. Infrared is invisible but it is a major part of the heat you feel through glass, and it is what the nano-ceramic layer in Kepler IR and IR+ is designed to address, alongside ultraviolet protection for you and the interior. Because that work is done by the ceramic technology rather than by darkness, lighter shades remain genuine solar control options. Performance figures are published per film and shade, so compare the exact combination you are considering and ask your installer which one suits your car and the way you drive it.