On the way home from Ohio to San Diego I stopped in West Texas at a state park where the temps were about 105F. My Itasca Navion has the 15k BTU heat pump option and in those conditions it could barely keep the rig below 90F during the day - no shade, no windshield cover as I had just bought the MH. Since then I have bought a windshield cover and cut pieces of Reflectix to fit between the cover and the glass of the windshield and the two door windows, thus keeping the solar radiation from reaching the glass. Huge difference - now I can keep cool on the hottest days. I do use a fan on the floor between the front seats, blowing toward the rear - very helpful.