Rvs don't heat up like cars. They have a much, much smaller ratio of window area and the non-window area is insulated. The windows are vertical and can be shaded with blinds/curtains or reflective panels to reduce radiant heat gain. The roof is highly reflective. So, you will find that a vent fan like a Maxx or Fantastic will keep the inside temp at the same as the outside temp. If it's 80, it'll be 80 in the RV. I live in the desert. When I park in my driveway for getting ready, I run the fan on high and it is always within a degree or two of the outside temp, even with the blazing AZ sun
