I am considering buying a 49' boat that is currently in California. I want to bring it up to the PNW but want to ensure the boat has sufficient heat source for our climate. This is what is listed in the specs: •Air Conditioning (Heat/air) (Marine Air) 3 zones Can anyone comment on this system and it's adequacy to keep the boat warm in the shoulder seasons in the PNW. If it was not sufficient how much would retro-fitting another system cost, and what would be recommended? Thanks.