The two units we have will cool the
boat on a hot July day in centeral
Florida but they are a little undersized. It takes a while for them to cool the boat down however they will do the job and at night no problem. As far as cost, the units were in the boat when we bought it. Unlike a home a/c unit everything is contained. The only thing you need to do is run the duct work,
electric, drain for the
cooling water, and a
pump and
water inlet for
cooling. Ok may be a big deal sorta but could be done
diy. You could sub some of the work out if you needed to. If your going to add a
generator later on units bigger than ours are going to require a larger generator. Hope this helps.