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Why Is My RV Air Conditioner Blowing Warm Air?

Since many RV owners live near the south, where air can be warm and humid throughout the spring and summer, AC is necessary. Hearing your air conditioner turn on only to have not the room not cool down is both unexpected and unpleasant!

We are here to walk you through a few steps about what you can do if your air conditioner is blowing warm air. While most RVs come with a furnace on some level, it’s their job to blow warm air – not your air conditioner.

Warm air coming through your RV air conditioner isn’t a great sign, but it’s usually easily fixable and diagnosable. One of the biggest obstacles for some RV owners might be getting on the roof to see the problem with their own eyes.

Why is my RV air conditioner blowing warm air?

We’ll be up front here. An RV owner might be able to diagnose why their air conditioner is blowing warm air. In some cases, the purpose of learning why your air conditioner is not working properly is moreso to communicate the issue to a professional. 

RV owners can be do it yourselfers, but air conditioners can also be a bit sensitive. Consider looking at it but asking for help before fixing.

Freon problems

Freon is the chemical most air conditioners use to chill incoming warm air. Freon effectively recycles itself and shouldn’t need a “recharge” often. The most common problem with Freon involves a leak, as having too little Freon will send warm air through an empty tank and into your RV.

Check the outside of your Freon container for a leak. It could be dripping. There is also a specific way to test the pressure in your Freon cylinder using a pressure gauge. 

We would provide instructions on how to add Freon to your air conditioner, but we just suggest you first learn what kind of Fredon your air conditioner takes. You can then order a kit and follow the instructions carefully.

If you do have to add freon, you might also need to seal up a leak in your Freon cylinder, as it doesn’t “run out.”

Note: Freon is not the safest chemical to work with. It can freeze skin given it’s ability to cool down air. Don’t touch without a bare minimum or disposable gloves and goggles. Freon is intended to be in a container for a reason. Also, if you do discover a Freon leak, turn off the air conditioner right away.

A fan problem

“Warm” air from your air conditioner is relative. The issue might be that the fan is not spinning fast enough to push cold air.

A poorly charged capacitor can also be a problem. The capacitor is a battery that helps the run start and maintain full speed, allowing air to be pushed into your RV.

The capacitor is relatively easy to replace. You’ll want to learn what size and voltage capacitor you have. Naturally, turn off all the power to your AC before replacing. Reconnect the new capacitor the same way the old one was hooked up.

Seeing a fan problem is also relatively easy. The fan might be spinning slower than it used to.

AC compressor

Your AC compressor is driven by a motor and helps keep coolant flowing. Symptoms of an AC compressor issue are either an exceedingly quiet or loud air conditioner, warm air, or even a circuit tripping in your AC – causing the AC to stop running.

The fix is generally to diagnose and replace the compressor itself. While it’s possible for a do it yourselfer to do this, we might suggest seeking a professional air conditioner repair person. Air conditioner compressors are more difficult to replace than the capacitor.

Dirty air conditioner

An air conditioner full of debris, junk, dust, or anything else could readily warm your air. Turn the power off to your air conditioner and take the lid off. You might find way more than you expected 

Cleaning out your air conditioner is relatively easy. Get gloves, maybe a scraper and possibly a hose to rinse off various parts. The result might actually be colder air than before too with the ability of all mechanical parts to work more efficiently.

Let the air conditioner also sit and dry for a bit before turning back on. Air conditioners could definitely use yearly cleaning as the build up over time can be detrimental – they are also easier to clean when they aren’t as built up.

Bad thermostat

Your air conditioner cannot tell what temperature air it’s blowing with a good, working thermostat. A bad thermostat results in an improper mix of warm air and cool Freon being sent from the unit to your RV. 

So yes, your air conditioner is capable of sending lukewarm or warm air into your RV – not on purpose, though! 

Thermostats are readily replaceable, generally by a professional though you could do it yourself.

Repairing your air conditioner

Half the challenge with repairing your air conditioner is that it’s generally on the roof of your RV. You also might not know right away the source of an issue. While we would fully advocate for people fixing their own things to save some money, this might be a situation to get some help if you aren’t sure about things.


Getting your air conditioner running again may be a simple matter of observing how your air conditioner has changed. Your air conditioner is certainly capable of making different sounds or acting different, including having issues with power.

Our advice covers most of the moving parts that would result in your air conditioner blowing warm air. Cool air is great for RV owners who are likely in a warmer climate where having some nice air conditioning can take the edge off a hot day.

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