In hot climates, I think a minimum of 16000 BTU's is required to keep the boat cool. I have an unusual set up. 12000 BTU unit under the forward dinette settee with ducts for the main cabin/galley. A second 6000 BTU unit was added under the V berth with ducts for the V berth area. I think this was added as an after thought. The previous owner had 3 small children that shared the V berth in a bunk bed arrangement. Water intake is through a thru hull in the forward hanging locker, seperate exhaust thru hulls above the water line. The Main unit is wired through the A/C CB/Switch on the panel, the second unit is wired into the Outlets CB/Switch. I have to be careful with the electrical load or the main CB blows. A seperate circuit would be recommended way to go and a future project. We added a 12v "clip on" fan with a long lead to help cooling. Clip it to the aft cabin door to help cool the aft bunk, clip it on the galley side storage door track to cool the chef or point it forward to the dinnette. All my duct work is on the stbd side, still trying to figure out a way to get a duct into the aft cabin. Although with the bimini/dodger up, the aft cabin doesn't get as hot as I had imagined it would. I like the 2 unit set up. I think one up forward and one in the suggested location in the port locker/head makes best sense for cooling/routing of ducts, but the added weight will add to the port list.