I have 3 15K roof airs and have had the roof coated with heat reflective coating from CoachWorx in Clearwater Florida before this summer trip. With the bus not heat soaked I can run two airs on low and the galley on auto, which it will cycle off and on and it has kept the bus very cool thru the hottest of days here on this trip in Texas where temps have hovered around 100 each day. While driving I will use the dash air also like everyone else does no matter what system they have if its hot.