6 Reasons Why an RV Air Conditioner Freezing Up

www.rvtalk.net is reader supported. When you buy through links on our site, we may earn an affiliate commission.

What’s the worst thing that could happen on a family vacation? It’s a beautiful hot day and you’re lounging in your RV, enjoying the cold air from the RV air conditioner. Suddenly, you hear that dreaded “click” sound of ice cubes clinking against each other. Your air conditioner has frozen up again! A quick assessment reveals that there could be several reasons for the RV air conditioner freezing up.

Why is my RV air conditioner freezing up? Before finding out the reasons, you should know the symptoms of this problem, so there is no misdiagnosis.

How Do You Know If the RV AC Freezing up?

If it’s the first time your camper AC freezing up, you may not even understand what is happening. Well, it’s likely to happen on a hot humid day when airflow through the ceiling vents drops to the level of almost nil before stopping completely. At the final stage, the compressor will stop functioning.

When the airflow slows down and then drops to zero, it happens due to the ice formation on the evaporator coil. Some people may mistake this symptom for a fan motor malfunction but it actually happens because of the freezing up issue.

RV air conditioner freezing up

What Causes the RV Air Conditioner Freezing Up Problem?

Why does my RV AC freeze up? If you have ever faced the trouble of an RV air conditioner freezing up, you know how inconvenient it can be. When the RV AC freezes, it could be because of these common reasons:

Dirty air filters

If you notice that your air conditioner has started freezing up, it could be because of a clogged air filter. Dirty filters cause the unit to freeze since they prevent enough airflow required for cooling.

You can fix this problem by simply cleaning the filter with soapy water. If the dirt does not come off easily, soak it into a vinegar solution for at least 15 minutes. It will be better to remove the old filter and replace it with a new one every year.

Displaced flow divider

What causes RV AC to freeze up? As you have already understood that the main reason for RV air conditioner freezing up is poor airflow. And another component that can obstruct the airflow is a displaced flow divider.

A flow divider or baffle is a separator between the hot and cold air. If it’s dislodged or its sealing wears out, it will leak cold air into the hot air inlet. This will make the hot air cold, which will literally turn into ice when the AC system will try to chill it further.

You can easily solve this issue by repositioning the divider and fixing its seal (in case it wears out).

Low refrigerant level

If your Dometic air conditioner freezing up repeatedly, this must be the reason. When this happens, the compressor will shut down after it tries to cool off too much refrigerant.

The AC units in travel trailers as a closed system. It means that there is no way to lose Freon unless it has a leak somewhere. Also, such units don’t have a service port for adding extra refrigerant if needed.

So, if your RV air conditioner freezes up because of low refrigerant, the only solution is buying a new AC system.

Faulty thermostat

A malfunctioning thermostat can also be the reason for an RV air conditioner freezing up. This problem could be prominent with old thermostats, which have a high rate of giving an inaccurate reading.

If the temperature reading on the thermostat does not match the room temperature, the culprit here is the thermostat. You should change it and buy one that is compatible with the trailer’s AC unit.

High humidity

If humidity levels are high, the evaporator coils will be iced up. This is because when the air in your RV is already humid, it cannot hold any more water vapor. So if a new supply of moisture enters through your cooling system, it immediately turns into ice upon encountering the cold coils.

You can prevent this from happening by decreasing the overall humidity in your RV. Run the fan at high speed when you are camping in hot and humid places.

Are the coils the culprit?

An air conditioner has evaporator and condenser coils that suck hot air in and blow the heat to the outside, respectively. When these coils start to get dirty, they block airflow and stop cooling efficiently. Less efficiency from these coils means the AC unit needs to work extra to blow cold air.

When dirt and dust accumulate on these coils, you will notice a significant decrease in performance. Because of reduced airflow, ice will form on the coils, affecting the compressor’s performance.

This is one of the most common reasons for an RV AC keeps freezing up. You can fix this by simply cleaning the coils and checking for ice formations.

rv ac freezing up
The coils could be dirty. (Credit: Love Your RV)

How to Fix an RV Air Conditioner Freezing Up?

As you can see, there are many reasons your air conditioner may freeze up on your RV. However, before you call the repair company or search for replacement parts online, you should do some simple troubleshooting.

First, you should turn off your RV’s air conditioner and see if it starts up again. If it does not, there is probably a problem with one of the internal components of the system, so you should call the repair company to fix the air conditioner instead.

However, if nothing seems wrong but your AC still freezes up, you can try to remove ice from the coils or change a faulty thermostat. Fixing an AC freezing up issue is an easy task that can be done by anyone with some basic knowledge of refrigeration systems. Following these simple steps should fix the problem within no time.


If you notice that your RV air conditioner freezing up, it could be because of a number of reasons. We’ve provided 6 common ones in this post and how to fix them quickly. Whether the issue is lack of refrigerant, dirty filters, or high humidity levels — all are relatively easy to troubleshoot on your own without calling for professional help.

About Chris Coleman

Chris Coleman is an interesting travel blogger and outdoor photographer with a great sense of humor. He owns an RV Accessories shop in New York City so he has the knowledge necessary to provide thorough reviews and give advice on how to choose the right products for RV travel. He puts all that RV knowledge and experience to good use in his sharing posts. Besides product buying guides/reviews, Chris also writes informative articles, how-to articles and RV camping guides in his own interesting viewpoint. Chris’s blog is one of the most reliable information sources for RV campers no matter if you're an expert or a determined beginner.

Leave a Comment