I was told 11 years ago when I bought my forst camper that a cover was not a good idea here in CO, because it will "cook" your camper (if the wall are laminated, the wall may buckle, the silicone will drip) and trap the moisture instead of have it evaporate in our dry weather. I have never used one, but I have protected my roof with a large, heavy tarp a couple of winter, because my camper was stored outside under a tree.