Your Cruisair AC System Can Also Heat Your Boat!

Cruisair Boat Heater

Have a Dometic Cruisair AC System, and starting to feel that fall chill? Thanks to Dometic’s reverse cycle / heat pump set up, your unit can also serve as a heater for your boat.

The basic principle of any air conditioning system is the transfer of heat from one element to another. In a seawater-cooled AC unit, the heat is transferred from the cabin air to the refrigerant gas to the seawater. However, when the Crusair unit is switched into heating mode, the refrigerant flow is reversed and heat is transferred from the seawater to the refrigerant gas to the cabin air.

Take note though… while Crusair Air Conditioners are among the best (if not the best) cooling AC systems for boats, reverse cycle heating will only work at full capacity in waters as cold as 50°F – 55°F.

Once you get below 40°F, your unit’s heating will be running at 50% capacity.

  • To find current water temperatures in your area, see here.
  • To see historical water temperatures for different parts of the country, see here.

Note: if you are in waters colder than 40°F, and have a Dometic water chiller system, you can purchase auxiliary heaters – placed in front of the blowers – for the air handlers of your system. Just contact us if needed.

Boat Cabin Heaters

Almost every Dometic system is reverse cycle: including all the Turbo self-contained units, Emerald, R-Series and Turbo Vap Split gas systems, and all of the water chillers.

How Reverse Cycle Systems Work, and How Your Cruisair Air Conditioner Can Serve As a Heater For Your Boat

Most Cruisair, Marine Air and Dometic AC Systems have a reverse-cycle mode, which changes the flow of refrigerant and turns your AC system into a heat pump.

Reverse cycle uses pretty much the same principle as air conditioning, except the refrigerant flows in the opposite direction.

The compressor pumps hot, pressurized refrigerant into the air handler where it transfers its heat to the cabin via the flow of cool cabin air over the coils. The refrigerant then flows through the expansion valve to the condenser, where the now very cold refrigerant picks up heat from the seawater and carries it through the compressor to the cabin.

You Should Regularly Turn On the Reverse Cycle, Just As Part Of Your Boat’s Maintenance

Cruisair heater reverse cycleYou may never switch to reverse cycle when it’s not needed, but you should consider doing so: the reversing valve in the system can stick if it’s not activated regularly.

And if it does stick, the heater will not work for you when you need it.

Along with cleaning the air filters and raw-water strainer, consider switching to reverse cycle for a couple of minutes on a regular basis, just as part of your scheduled maintenance. You should even do so during hot summer months… as temporarily uncomfortable as it may seem. You’ll thank yourself when temperatures drop.

*Tip: if the reverse-cycle valve sticks, tapping it lightly may free it; listen for a hissing sound as it activates. Tap it LIGHTLY, though..

Where To Buy Cruisair Units With Heating Option

We carry the entire Cruisair, Marine Air, and Dometic Brand line of AC units and parts. They nearly all come with the reverse cycle heating / heat pump option: Marine Air Conditioners

Questions on Cruisair Heating, or Boat Cabin Heaters? We’re here to help!

Have a good one!
3300 NW 112th Ave,
Doral, FL 33172
(800) 766-5256

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