We have the reflectix backed pillows that go into the ceiling vents to keep the heat out. Do you store you RV with the pillows still in place when storage is outside in full sun? Would there be too ...
suprz, if you ever have the need, Lance (part of the arctic package) makes a snap in place vinyl interior cover. 4 snaps get screwed in place in the 4 corners on the inside trim. The 14x14 vinyl pad gets snapped into place. They do a good job of insulating as well as blocking out sunlight. You can also unsnap two snaps and tuck it under itself to only cover 1/2 of the vent, allowing partial ventilation if needed.