A marine unit is more efficient because of the water cooled condenser, But
because it is marine, it is more costly. A larger unit is more efficient
than several small ones. A single unit will require more labor to install
and hence, be more expensive.
Steve

"MarshallE" wrote in message
. com...
Hi,

I want to add AC/Heat to my boat. (1942 80 ft. long) Previously it had
motor home style units installed in ceiling.

Is this the best way to go?

I get opinions from home style AC mounted to cabin roof, motor home style
to
marine AC with water exchanger.

What advice do you have? I am leaning towards the marine style and if I
choose this approach then I will have a second question...one large unit
or
several small units?

thanks,

Marshall