Indeed that is a possibility but if the caravan is properly insulated the effect is minimized. Secondly the shiny surface reflects light and heat (as opposed to painted surfaces in dark colours) Finally the caravan should not be traveled in, for safety reasons, as it is being towed. That is when the heat build-up inside would be most noticeable. Once parked, and you can choose a spot in the shade, the windows can be opened to allow for cross ventilation which significantly lowers the inside temperature.