Mermaid M9 – Cool & Reverse Cycle Unit 9,000 BTU’s 220V

Boats wired for 220V power still need cooling and heating from a single compact unit, and the Mermaid M9 Cool & Reverse Cycle covers that case at 9,000 BTU — sized to handle roughly 800 cubic feet of cabin space on boats around 30 to 32 feet. It shares its stainless steel base with Mermaid’s smaller M6 unit, keeping the same compact footprint even with the added reverse cycle heating function built in.

Why Choose the Mermaid M9 Reverse Cycle

Reverse cycle heating means one unit does both jobs rather than pairing a cool-only AC with a separate heater, which simplifies wiring and reduces the number of systems to maintain onboard. Boats that only need cooling, with no plans to use the boat in cold weather, might find the cool-only M9 configuration a simpler and slightly less complex option instead.

Mermaid builds these by hand in the US, selling roughly 900 to 1,200 units a year across boats ranging from small cabin cruisers to 75-foot yachts — a detail worth weighing if lower-volume, hands-on manufacturing matters to your purchase decision.

What to Know Before Installing

• Pump is not included and must be sourced separately
• Ducting requires both 6″ and 4″ runs, with at least three 4″ round supply grilles
• Air discharge position (right, left, or top) must be specified before ordering
• Confirm exact running amperage for this specific 220V/reverse-cycle configuration directly with Mermaid before finalizing your electrical plan