A couple of years ago I installed two air conditioners from Flagship Marine:
http://www.flagshipmarine.com/
These are the same ones used on USCG and Canadian CG vessels. I've been very happy with them.
Unlike the CruiseAirs, these units are not reverse cycle. They have a large electric heating element to provide heat in winter (about 2,000 watts each). I felt this was more efficient, less complicated (no
pumps running or filters to get clogged), and safer. Through 2 complete winters I found that just one of these kept the boat (42' sloop) at a comfortable temperature except on the very coldest nights when additional heat was required.
My boat is in Washington, DC at the moment. Would be happy to show you these units anytime.
Bill
S/V Born Free