Cabin air conditioning on a Komodo liveaboard is a humidity problem as much as a temperature problem, and it is the largest single electrical load on the boat. Undersize it and guests sleep badly; oversize it without humidity control and you get a cold, clammy cabin with condensation behind the joinery. Both outcomes are avoidable at design stage and expensive to fix afterwards.
The tropical load is not the temperate load
Equatorial conditions mean high ambient temperature with high humidity, day and night, all year. Solar gain through decks and hull sides is substantial, particularly on a steel or aluminium vessel where the structure conducts heat readily into the accommodation. The cooling load calculation has to account for the real conditions: deck and hull heat gain, guest and crew heat output, galley and machinery heat migration, lighting and equipment, and the ventilation air that has to be cooled and dehumidified.
Insulation is the lowest-cost part of the solution and the most commonly compromised. Money spent on deck and hull insulation reduces the equipment and the generator capacity you need for the life of the vessel — see generator sizing.
Humidity is the guest comfort variable
A cabin at a comfortable temperature but high relative humidity feels unpleasant, bedding feels damp, and guests wake up. A system that cycles hard on temperature alone can achieve the setpoint without removing enough moisture, which is why guests describe cabins as “cold but sticky”. Designing for latent load — moisture removal — as well as sensible load is what separates a cabin guests sleep well in from one they complain about.
Condensation is the structural consequence. Cold surfaces behind joinery and inside lockers in a humid boat produce moisture where you cannot see it, which on a timber vessel is a rot risk and on any vessel is a mould and odour risk. Vapour barriers, insulated ducting, drained condensate trays that actually drain, and locker ventilation are the countermeasures.
System architecture choices
Individual self-contained units per cabin are simple, low in capital cost, and fail one cabin at a time. They put a compressor near the cabin, which is a noise problem, and they multiply seawater connections.
Chilled water systems centralise the plant in the machinery space, put only a quiet fan coil in the cabin, allow individual cabin control, and scale well on larger vessels. They cost more, need competent installation, and a chiller failure affects everyone — which is why redundancy in the chiller plant matters on a commercial boat.
Direct expansion split systems sit between the two. On liveaboards above a certain size, chilled water is usually the right architecture precisely because it moves the noise source away from where guests sleep.
Noise — the detail that decides reviews
Guests judge a cabin on how quietly it stays cool. The noise paths are the compressor, the fan coil unit, air movement through undersized ducts and grilles, and structure-borne vibration through mountings. Specify generous duct and grille sizing so air moves slowly, isolate fan coils properly, avoid mounting equipment on bulkheads shared with a bed head, and keep condensate drains from gurgling. These decisions cost almost nothing at design stage and cannot be retrofitted without opening the joinery.
Redundancy and service
Air conditioning failure on a tropical liveaboard mid-trip is a serious commercial event. On chilled water systems, multiple compressors or chillers allow degraded operation rather than total loss. On individual units, spares on board and an engineer who can swap a unit are the equivalent. Either way, specify seawater pumps and strainers for easy service, because blocked strainers in warm biologically active water are the most frequent cause of an air conditioning fault out here.
The electrical consequence
Air conditioning at afternoon peak with full occupancy is normally the largest load on the vessel, and it coincides with compressor filling. That coincidence sets your generator peak. If you intend to avoid running a generator overnight, the night-time air conditioning load has to be small enough for a battery bank to carry, which argues for good insulation, efficient plant, and a reduced-setpoint overnight mode rather than shutting the system off entirely.
What we look at on a refit
Existing systems on older Komodo boats are frequently a collection of individual units added over years, with inadequate insulation, undersized ducting, blocked drains and a generator plant that was never resized for the accumulated load. A refit is the opportunity to fix the architecture rather than replace units in place. Scope on the refit page; the full specification chain on the specification guide.
Frequently asked questions
What air conditioning system is best for a tropical liveaboard?
On liveaboards above a certain size, chilled water systems are usually the right architecture because they move compressors into the machinery space and leave only a quiet fan coil in the cabin, while allowing individual cabin control. Individual self-contained units cost less but are noisier and multiply seawater connections.
Why do liveaboard cabins feel damp even when the air conditioning works?
Because the system is meeting temperature setpoint without removing enough moisture. Designing for latent load as well as sensible load is what produces a cabin that feels comfortable rather than cold and sticky, and it also prevents hidden condensation behind joinery.
How much of a liveaboard’s electrical load is air conditioning?
Usually the largest single load, peaking mid-afternoon at full occupancy — which coincides with dive compressor running. That coincidence typically sets the generator peak, which is why insulation quality directly reduces the generating plant you have to buy and run.
Talk to the build desk
Send the vessel details or the operating profile you want to run and we will tell you what has to be established before a number means anything. Quotations in USD. Construction, repair, refit and vessel-sale contracts are issued by PT Komodo Galangan Nusantara.