Sunlight reaching your Tesla's glass includes visible light, ultraviolet and infrared energy. Infrared is invisible but a significant part of what makes a parked cabin feel hot. Nano-ceramic film is designed to work on the solar energy hitting the glass rather than relying on darkness, which is why a lighter Kepler shade can still be a sensible choice for a hot climate. Because performance differs between films and between shades, compare the published figures for the exact film you are considering with your installer, and choose the appearance and performance combination that suits how you use the car.