I keep a portable air conditioner on my
boat, set at about 85° or so. The idea is for it to come on and run a little once in a while, and keep the humidity under control, and help change out the air. I made a flange for the
exhaust hose that fits in a porthole. My
electric bill usually only runs about $40/month when I do that, less in
winter, and it is a fairly big boat inside. I need a couple of sticks to reach up and open the skylight, and she is pretty fat, too, so lots of
interior space to condition. I used to have problems with hatches and drawers sticking, but no more. And no nasty odors apart from a faint aroma of
diesel fuel from the Westerbeast.