Marine Air Conditioners: Cooling Your Boat or Yacht

Marine air conditioning is a specialized field. The salty environment, limited space, constant motion, and unique power requirements demand purpose-built equipment. This guide helps you choose the right system for your vessel.

Types of Marine AC Systems

Self-contained units combine all components in a single housing that fits in a locker, under a berth, or in the engine room. They are easier to install and ideal for boats under 40 feet.

Split systems separate the compressor/condenser from the air handler, allowing more flexible placement. Better for larger vessels where noise isolation matters.

Chilled water systems use a central chiller that pumps cold water to air handlers throughout the boat. Standard on yachts over 60 feet.

Raw Water vs Air-Cooled

Most marine ACs use raw water (seawater or lake water) to cool the condenser — this is far more efficient than air cooling in a marine environment. The system includes a seacock, strainer, and pump. Air-cooled units exist for trailerable boats where water intake is impractical.

Sizing for Boats

Marine BTU sizing differs from residential. The factors include cabin volume, insulation (or lack thereof), number of hatches and ports, hull color, and whether the boat sits in direct sun. As a rough guide: plan for 14-18 BTU per cubic foot of cabin space.

Top Marine AC Brands

The marine AC market is dominated by Dometic (formerly Marine Air), Mermaid, Webasto, and Cruisair. For smaller boats, the Dometic Turbo series and Mabru Power Systems offer compact, affordable solutions.