Self-contained units are typically the best choice for smaller boats, up to about 40 feet (12m), due to the lower cost of both equipment and 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. Cool-only models are available, as well as reverse-cycle models that can cool or heat.
A single unit can cool each cabin, or can be ducted to 2 or more cabins to save space and cost. Self-contained units often require less power than other systems due to the highly efficient rotary compressors.