I am more looking to find out about noise levels in the cabin(s) based on where the unit is located. My boat is small (as you can see) so my options are limited. I am leaning towards behind the sink under the counter inside the cabin.
The exhaust run should have the cold air intake around the exhaust hose outlet, so heat shouldn't be an issue for the exhaust. I am not really happy having it exhaust on the stbd side of the boat, as I do as much docking as possible stbd side to. I also kayak, fish and shrimp, so exhaust placement should be away from where I play if possible.
The wire runs will be very short, oversize (as always), and probably done by a professional this time around. I am tearing out the counter top for a new oven and stove, so I am replacing the sink as well and would like to get the heater done in the same upgrade, all in one shot. That would be all of my stbd side upgrades in one whack and ready to go for the year.