Question 1

Why does my yacht AC system keep growing mold in the ducting?

Accepted Answer

Marine HVAC systems produce far more condensation than residential units because they cool humid tropical air while the boat sits in warm water. That moisture collects in duct low points and drip pans, creating ideal mold conditions. The fix is multi-layered: ensure all ducting slopes toward drain points, install UV-C germicidal lights in the air handler, use antimicrobial duct liners, clean drip pans monthly with marine-safe biocide, and run the system in fan-only mode for 30 minutes after the AC shuts off to dry the coils. Most yacht HVAC mold problems are design or maintenance issues, not equipment failures.

Question 2

How much does it cost to replace a yacht AC system?

Accepted Answer

A single-zone marine split AC unit (Dometic, Marine Air, Webasto) costs $2,000-$5,000 installed. A full chiller system for a 60-100 foot yacht runs $25,000-$80,000 including ducting, fan coils and controls. Replacing just the chiller unit on a superyacht is $15,000-$40,000. Annual HVAC maintenance contracts run $1,500-$5,000 per year depending on system complexity. The biggest hidden cost is ducting — corroded or mold-damaged ducts can double the project cost.

Question 3

Should I choose a chiller system or individual split units for my yacht?

Accepted Answer

Split units (self-contained or reverse-cycle) are simpler, cheaper and easier to service — ideal for yachts under 50 feet or boats with 1-3 climate zones. Chiller systems are more efficient at scale, quieter in the cabin, and allow unlimited climate zones — the standard for yachts over 60 feet. The trade-off is complexity and cost: if the chiller fails, the entire boat loses AC, whereas individual splits fail independently. Many mid-range yachts use a hybrid approach with a small chiller for main zones and a standalone split for the pilothouse or crew quarters.

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