Learn More About Boat AC Repairs

How much does it cost to put air conditioning on my boat?

Like many marine repairs, there are many variables that make it difficult to give estimates for marineac for boat owners. To install marine air conditioning on a boat that doesn't have it today, you'll need to install a below water raw water strainer and an above water line water discharge.

You'll also need to install a condensation pump, new shore power, new circuit breakers, run all the ductwork, install air returns, air vents and a thermostat. You can see more details here on how to do DIY marine AC installation (bottom of the page).

A good rule of thumb is that a professional high quality marine airconditioner installation is 5-10x the cost of the unit itself. There really aren't airconditioning retrofit units or retrofit kits available for most units as technology and vendors have changed quite a bit. Replacing an existing AC unit can vary from 2-5 times the cost of a unit depending on how many components need to be replaced or reinstalled.

How long does it take to install marineac? Does my boat need to be out of the water to install my new marine airconditioning unit?

Heating my boat
Heating your boat with a marine heat pump

For most customers, BoatAC.net can install marine air conditioning and have your boat ready to go within 1-2 weeks. You'll be comfortable this season with complete humidity and temperature control in your living space. We also offer emergency service if you’re on a tight timeline.

If you have an existing system, we can usually replace it while the boat is in the water. If you don't have AC and want it installed on your boat, you'll need to have the boat out of the water to install the through hull(s).

Should I fix my Dometic Cruisair SMX or replace it (or my Marine Airrr Systems or older Dometic marine unit)?

Most marine air conditioning units last around 10 years. In most cases, replacing something like a condensing unit or condensing coil can cost as much as replacing it with a new unit. New units operate as reverse cycle marine heat pump air conditioners - using unlimited sea water to improve energy efficiency.

[note: make sure you keep all of your air filters clean. Problems with air flow are a common cause of premature wear and failure.]

Generally, if your circulator pump is running and your compressor is on and you don't have cold air or a frozen coil, your unit doesn't have refrigerant and will probably cost more to fix than to replace. A frozen coil means that you likely have an airflow problem - which is probably related to a dirty filter or other obstruction.

New systems, like the 16000 BTU Marinaire unit we install frequently, are much more energy efficient, run quieter and come as one self-contained ac system. Because marine a/c units cycle raw water through your unit, it is important that your boat's a/c unit be properly installed and in good mechanical condition.

We often are asked "how do I add freon to my marine air conditioner?". In most cases, this leads to a decision to replace their boat air conditioner unit with a new on. 

How do you size a marine air conditioner? Should I upgrade to the biggest marine air conditioning unit that will fit?

Marine air conditioning sizing is a bit complicated. In order for your unit to operate efficiently, you need to have the right size return and vents for the power of unit you have. If your unit has too much power for the amount of airflow, the coils can actually be damaged or even freeze!

If you have too much airflow, the unit may not be able to actually cool or heat your boat at all. This may also apply to the volume of water that can go through your existing plumbing.

To make things even more complicated, some units rated for the same power actually require different amounts of airflow and water. And, if you have too large a unit, it may cycle on and off much more frequently as it heats or cools your boat too quickly with too much airflow. We can help though! Please give us a call and we can help you design the right marine air conditioning system for your boat.

I have a Cruisair marine air conditioning unit or a Marine Air Systems unit that I’d like to replace, but I can’t find a similar model online. Do you have any of those units?

air conditioning for boat
Give us a call with any boat ac related questions or service.

After Dometic acquired Cruisair, they updated the designs on most models. The good news is that their new units and competitor’s marine air conditioning units. We prefer units from Marinaire and Mabru Power Systems. These are quieter, more efficient and overall higher quality.

The bad news is that they aren’t identical and don’t simply plug into the same connectors. However, we have a lot of experience updating Cruisair split systems to new self-contained systems and are able to re-use many of the components. We don’t recommend trying this yourself unless you have a lot of HVAC and marine repair experience.

Does my boat need to be out of the water to install my new marine air conditioning unit?Guide to Installing Marine AC

We can perform most marine air conditioning replacements or upgrades while your boat is in the water. If we uncover any safety issues, we may not be able to finish the work without pulling the boat out of the water. New marine air conditioning installations require the boat to be out of the water because they require installing strainers under the water line in the hull to circulate chilled water.

What is the best marine air conditioner unit for my boat? 

There are a number of good vendors today. We prefer Marinaire and Mabru Power Systems for most customer installations. They are quiet, durable and efficient. They are also very well designed, with sound insulation on noisy components for whisper quiet operation and have stainless steel condensate pans so they won't rust.

Can you install a marine air conditioning unit I’ve already purchased?

In most cases, we are happy to install new marine ac units that customers acquire on their own. However, we won’t install second hand or damaged units. We require that customers provide us with the brand and model of unit before we schedule the install so we can procure the necessary accessories.

The interior of my boat is beautiful. I don’t want to ruin the aesthetics by installing marine air conditioning. Will my boat interior look the same after your installation?

We take pride in our craftsmanship. The owner of Boatac.net, Eric Brown, is a master carpenter who built a successful millwork business (EDB millwork).

We are committed to factory quality installations of marine air conditioning systems whether they are located in the engine room or under your galley's seating. We use marine-quality parts to match your boat's interior - like MSI teak return air grills.

How do I prime my boat AC system to get water flowing? How do I add freon to marine air conditioner?

Generally, once you've opened up the main valve, water should fill your system or be available to replace the marine antifreeze that you may have in your system. If you turn on the AC system and don't see water coming out, the most likely cause is some air trapped at the top of the strainer cap.

To fix this, turn off your AC system. With the through hull valve closed, check the strainer basket for any debris and clean it. Next, with the strainer cap off, open the through hull valve - while ensuring that you'll be able to quickly close it.

You will probably see water start flowing out of the strainer. As soon as you do and any air bubbles are gone, close the through hull valve and replace the strainer cap. Make sure you're careful with the threads - you don't want to strip them. Then, reopen the valve and turn on the marine ac unit again.

If the water still isn't flowing, we suggest giving us or another marine mechanic a call. It is likely that there is debris stuck somewhere in the system. We come to each service call with compressed air, powerful vacuums and special fittings to be able to clean out any debris and get your boat AC system running again.

Also, watching our de-winterizing video may help as well (this link jumps right to the strainer part of de-winterizing).

I just turned on my marine air conditioning unit for the first time this season and it shut down. What’s going on? Can you help me with troubleshooting boat AC to make my air conditioner work? 

There are many safety features in marine a/c units to prevent leaks, overheating or other problems. In newer devices, the thermostat may show a code like P3, P4 or PS (looks like P5). Typically, those codes indicate leaks in refrigerant, insufficient water flow or obstructed airflow. Unfortunately, it can be very time consuming to properly diagnose root causes and often costs as much to fix as to replace.

Where can I install a marine air conditioner on my boat if I don’t have one today?

Prior to scheduling a new installation, we will schedule an in-person boat inspection or a video call. We will work with you to determine the optimal location(s) for your marine air conditioning. Our professional installers understand the limitations and requirements for new marine ac installations.

We will also consult with you about the ideal locations for the ducts, vents and returns.

Will my bilge pump run all night if I’m running my air conditioning unit?

Boatac.net will install a separate condensation water pump that connects to the condensation drain that will quietly pump condensation out existing through hull ports. This way, your bilge pump won’t be turning on all night as your marine air conditioning cools your boat.

Can BoatAC.net replace my Marine air "split system” with a self-contained unit?

Yes! We can replace your existing split system with a new self-contained marine air conditioning unit from Marinair or Mabru Power Systems. The new marine air conditioner will be much quieter, efficient and reliable than your old system. It will also offer heat and humidity control.

I’ve been searching everywhere for what the error code means on my current marine air conditioner. Can you help me figure out what’s going on? What is an HPF error on my Dometic AC?

We offer repair services to help diagnose and resolve marine air conditioning issues. Just fill out the contact form or give us a call. If your unit was installed 10 years ago or longer, it is probably less expensive to replace your marine air conditioner than to fix it.

Because of the harsh marine environment and tough work that marine a/c units do, their main components tend to begin failing after around 10 years. Obviously, there are many factors that could lengthen or reduce the lifespan of your unit.

What does a LO or LO / AC error on my marine air conditioner mean and what causes it?

Marine air conditioning units are very sensitive to fluctuations in electrical current. They need to be provided with consistent voltage and amperage to function appropriately. As a result, most modern marine ac units will shut down automatically when they detect the wrong voltage or other irregularities in the electricity coming to them.

There are myriad issues that can cause this such as corrosion of wires, grounding problems, too much load on your boat’s electrical system or internal electrical component issues. Give us a call and we're happy to help you figure it out.

What do Hi PS or Low PS error messages on my marine air conditioner mean and what causes them (btw, PS often looks like P5)?

Both refer to the pressure in the compression system in your marine air conditioner that creates the cooling effect that ultimately cools the air blown into your cabin. Low pressure usually indicates a leak - which could be too small to be seen with a naked eye. High pressure usually means that there is an issue with the flow of refrigerant through the system.

This can result from blockages or kinks in hoses, damaged coils or similar issues. Unfortunately, both of these tend to be very time consuming to diagnose and resolve. We strongly recommend against adding more refrigerant to a marine air conditioner that is known to leak.

Even small leaks often grow quickly and could damage your unit or even cause more serious issues. Give us a call and we're happy to walk through some options with you.

What does PE (Program Error) on my marine air conditioner display mean and what can I do about it?

PE stands for program error and means that there is a software problem inside the electronics that control your marine air conditioner. Your unit will likely shut down in response to this error.

Often, these errors require a professional diagnostic, though some boat ac units may allow you to swap out the electronic components. In some cases, these errors may also be caused by other issues that the system hasn’t properly diagnosed. Give us a call and we're happy to help find a solution.