Boat Air Conditioning: A Basic Guide

Stay Cool On board

No matter what part of the country you live in, air conditioning can be a vital asset onboard your boat. As part of a total HVAC system, it can help protect the value of your investment through preventing mildew, mold, and unwanted odors by keeping your vessel dry in even the most humid conditions. Plus it offers an extended chance to enjoy your boat when the weather isn’t ideal by keeping you cool and comfortable. There’s a lot to consider when it comes to climate control and ventilation though, so you’ll need understand all the basics in order to get the best system in place on your vessel. This guide will help you learn the essentials of boat air conditioning.

Boat Air Conditioning Marine Ventilation Boat air conditioning can be a vital asset onboard. Photo via Pond5.

Why Do You Need Climate Control On A Boat?

On a boat, it might not occur to you that climate control should be a concern. However, it’s something that should be in place to keep your vessel in the best condition possible. On boats with enclosed cabins, berths and compartments, climate control and ventilation will assist with things like:

  • Reducing musty air, humidity, and moisture below deck
  • Creating a drier environment thus extending the life of fabrics and electronics
  • Reducing the incidence of blistering as a result of hull moisture saturation

Types Of Marine Ventilation Systems

Climate control systems typically include two types of ventilation: active and passive. Active ventilation refers to systems that include a fan that keeps air moving, which is operated via the boat’s power or solar energy. Passive ventilation refers to clamshells, grilles, ports, and other vents that simply provide a path for air to move around the boat. Of course, passive ventilation isn’t going to be effective on its own and on the stale days, it may not seem to be effective at all. Therefore, you will likely need both as part of an integrated heating, cooling, and ventilation system.

Who Makes The Best Marine Air Conditioning?

Choosing the right system is just as important as choosing to invest in climate control at all. There are several different options for air conditioning on board your boat with various factors to consider, no matter what you have in mind. From small systems that are portable and easy to use, to integrated central air systems for larger yachts, a variety of systems and units are available. Many of the systems available these days offer heating as well as cooling (known as reverse-cycle heating/cooling systems). Some of the biggest names in marine ventilation and boat air conditioners are Dometic, Mermaid Manufacturing, Webasto and SeaFlo.

Boat Central Air Conditioning

Central air conditioning units for boats are available in split systems, which are designed to split the cooling between two separate units connected by tubes that transfer refrigerant back and forth, creating the cool air from a condenser unit in a mechanical compartment that is then evaporated and blown out through the blower inside the cabin. This system is the most common option for central installation on medium to larger size private motor yachts and cruisers in the 40-80 foot range.

Those who don’t want to use refrigerant can choose the eco-friendlier chilled water system, which functions the same as a central air unit, but by using chilled water instead of refrigerant in the copper lines between the units. This system can provide the same (or greater) cooling capacity than what is offered by a split system, and is often the preferred option for larger boats.

Some of the best solutions for split systems currently on the market are the Cruisair Split-Gas DX air conditioning systems from Dometic that pair high-performance Emerald R410-A evaporators with state-of-the-art Emerald Series condensers.

Self-Contained AC Units

A self-contained unit will typically be mounted in a locker or under a bunk, operating by drawing in cool water from a thru-hull connection and combining it with eco-friendly refrigerants that create cool air. This air is then blown throughout the space by the blower motor and fan. These units are ideal for boats in the 20-40 foot range and come in a variety of sizes and styles.

Dometic’s EnviroComfort reverse-cycle air conditioner is a popular, self-contained unit with a 16,000 BTU capacity.

Hatch-Mounted Portable Units

For those who just want something more like a portable window unit that they might purchase for home use, the hatch-mounted portable AC is the best way to go. This system can install as a mount on any hatch or window, offering direct and limited cooling for a single space on the boat. These are great for small boats, such as sailboats, cuddy cabins, pilothouse boats and vessels with a small console berth or head.

The Cruisair Carry-On 7,000 BTU portable air conditioner is a good example of a hatch top unit designed specifically for the marine environment. This unit is ideal for boats up to 30-feet in length that may be too small for larger central split systems. This unit can also be carried on and off the boat by one person fairly easily.

Boat Air Conditioning Installation

While the portable and self-contained units may be easy enough to install on your own, the central air conditioning systems available for boats will typically need to be installed by a licensed professional. Not only will this guarantee proper installation, but it will give you peace of mind that you’re getting the right size system to keep your boat at the optimal temperatures, no matter where or when you head out onto the water.

Regardless of which system you choose, every compartment that can be closed off from the rest of the boat should have its own vent(s) to ensure proper airflow throughout the vessel. You’ll most likely want to be able to run your air conditioning while cruising or out at anchor, so you will need to have an adequate battery bank to support the required load, and/or have a capable genset onboard.

When choosing the system that you will install, you will need to consider things like:

  • Required cooling capacity
  • Location of the unit(s)
  • Number of units
  • Duct and grille sizing
  • Seawater cooling components

A boat air conditioning professional can assist you in selecting a system that suits your needs and provides the amount of cooling that you desire. They can even help design the system and ensure that it is installed properly to give you the best cooling for your boat, no matter what climates you find yourself boating through.

When you do install an air conditioning unit, you’ll want to make sure that all of the connections are secure, and that you have the means to power the system when you’re out on the water because air conditioning is only useful when it’s working.

Why AC On Your Boat Is Important

If you’ve never considered air conditioning for your boat, it may be time to change your mind. Now that you understand a little more about the value of this feature and what it can do for the lifespan and protection of your boat, you will likely be more inclined to add it to your list. It’s also easy to find a diverse selection of products, no matter what you might want or what type of boat you have.

You don’t have to be an HVAC professional to get great air conditioning on your boat. Whether you choose a portable system or go for a full central unit installation, you can trust that you will find the best products if you keep this information in mind.


Marine cooling BlueCool C-Series air conditioning unit is extremely quiet to run. Image credit: Webasto


Do boats come with air conditioning?

It may sound obvious but you will need an enclosed space to store air conditioning units and to reap the reward. Yachts are the most common type of boat to come with air conditioning units, however air conditioning units can be installed on any boat.

Some of the most popular boat brands which include air conditioning units in some of their models include Sea Ray, Linssen, Monterey, and Bertram.

How much does it cost to add air conditioning to a boat?

Depending on the size of the unit, you should be able to install two units on your boat for less than $4k. However, if you get a professional to install it you will need to consider the cost for the labor too.

What is a refrigerant?

A chemical compound that is used n the refrigeration cycle of air conditioning systems. Refridgerants are the heat carrier, and are  converted from gas to liquid.

The most environmentally friendly refrigerants?

Hydrofluorocarbons (HFC) and hydrofluoro-olefins (HFO). HFCs are made up of fluorinated hydrocarbons. While HFCs contribute to global warming, they do not affect the ozone layer directly.

Written by: Valerie Mellema

Valerie Mellema is a writer, published author and avid bass angler who lives on the shores of Lake Fork in East Texas — the top bass lake in Texas and the fifth in the nation. For the past 10 years, she and her husband have enjoyed the pontoon boat lifestyle while fishing a lake that not only has bass but beautiful wildlife as well. She holds a BS in Agribusiness/Equine Business and regularly contributes articles to, YachtWorld and Boat Trader.


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