Solar energy reaching your car arrives as visible light, ultraviolet and infrared, and it is the infrared portion, which you cannot see, that does much of the heating you feel in the cabin. Kepler's nano-ceramic films are engineered to work across that spectrum rather than simply darkening the glass, which is why visible light transmission and heat performance are quoted separately. A light shade can still be a strong performer, and a dark shade is not automatically the cooler choice. Alongside comfort, filtering UV helps protect dashboards, trim and upholstery from fading over time. If heat is your main reason for tinting, tell your installer that, and compare the exact films and shades on the table rather than judging by appearance alone.