Every RV benefits from more insulation. That’s why the good Lord invented RV vent insulators (http://goo.gl/6R6hCW). These fit standard 14-inch RV vents.
Put three inches of foam between you and Old Man Winter. (Click the pic for more info.)
RV ceiling vents are great when you want to circulate fresh air into your living space. They work well because they are basically large holes in your roof. This has a few downsides with regard to heat transfer. They allow heat to enter your living space during the summer. In winter, they allow your precious heat to escape.
The reflective surface also helps keep your air cool in the summer! (Click the pic for more info.)
The Camco Sunshield RV Vent Insulator is simply a 3-inch thick piece of foam that’s cut to fit your vent opening. The upper side of the insulator is covered by a silver reflective surface that blocks UV rays.
The upshot is that this product keeps your RV cooler in summer and warmer in winter.