Self-contained marine HVAC units are typically the best choice for smaller boats up to about 12 meters (40 feet) due to the lower cost of the units and installation.
Illustration of Self-Contained Marine HVAC Installation
A self-contained air conditioner has all of the major components mounted on a single chassis, which is installed in the living area; usually under a bunk or settee, or in a locker. Cooling-only models are available, as well as reverse-cycle, which can cool or heat. Also available are air conditioning kits, which include the self-contained unit, water pump, ducting, and grilles -- all the components needed for a complete system.