Regarding the shrink wrap method. I live next to a few large marinas and have seen this trend from start to present. I saw many more boats go this route the first few years and it has sharply declined since. Better for me because in the evening I like to walk and look at boats. A marina full shrinkies was an eye sore. The few that are still using this method have
solar powered boat vents mounted in the shrink wrap. My guess is that many quit due to moisture trap and mold.
As a side note. When looking to install a fan in my
Boler I didn't want to cut a new hole and looked at those
solar powered fans. With advice from here
I went with something else with more CFM's. However those fans are designed for minimal air flow to prevent mold. They work great on boats in this environment and wonder why they haven't caught on in the RV world for the same purpose. They're small, inexpensive and need very little
light to run. Though they probably don't function well under a foot of snow