RV AC Not Blowing Hard Out All Vents

RV AC Not Blowing Hard Out All Vents: Causes and Fixes

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Last Updated on April 14, 2023 by Jessica Lauren Vine

Whether you live in your RV or you enjoy the occasional weekend camping trip, you won’t enjoy yourself if you’re uncomfortable. You might worry that RV AC not blowing hard out all vents is going to ruin your vacation. One of the quickest ways to get uncomfortable in the summer months is if your air conditioner isn’t blowing air out of all the vents. Unfortunately, this is a fairly common problem with all air conditioners, especially those found in RVs. 

The most likely reason your air conditioner has weak or low airflow is that you have a dirty air filter. The air filter’s job is to clean air that’s getting sucked into the air conditioner and filter out dirt and debris. If the filter gets too dirty, it will start to wholly or partially block the flow of air passing through it. 

While this is the most common reason, it isn’t the only possible explanation. Several other things could be happening, and we’ll delve into each one in this article. Hopefully, we can point you in the right direction as to why your AC is struggling and how to fix the issue. 

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03/30/2024 04:43 pm GMT

How Does My RV Air Conditioner Work? 

Before you start digging into what’s causing your uneven airflow, let’s go over a brief tutorial about how your RV’s air conditioner works. Essentially, your air conditioner acts as both a vacuum and a fan in one. When all is working as it should, the visible part of the air conditioner on the ceiling of your camper is sucking air out of your camper and into the AC. 

This air then cycles through an air filter or filters that remove dirt, debris, and other impurities. The clean air flows over super-cooled evaporator coils that chill the air. The chilled air gets blown back into your camper, either through the AC itself or through air vents, by a fan inside your air conditioner. 

If there’s a problem or breakdown with any part of the system, it will result in inadequate airflow to various parts of your RV. 

Possible Causes for Uneven Air Flow Out of the Vents 

Now that you have a better idea of how your air conditioner works let’s dive into possible reasons why some vents produce more air than others. 

Dirty Air Filter 

Like I said before, dirty air filters are the most common reason for poor airflow and circulation. The good news about this problem is that it means the filter is doing its job and cleaning the air. However, the bad news is that the filter is so caked in dirt and debris that it’s starting to block airflow completely. 

How to Fix a Dirty Air Filter

To clean your air filters, start by turning off the air conditioner. The air filters are typically on the bottom side of the inside portion of your RV’s air conditioner. Remove the outer covers on top of the filters to access the filters themselves. Take the dirty filters and run cool or lukewarm water over the top of them until they’re clean. 

You can also let them sit in standing water and soak. Once the filters are clean, give them enough time to sit and dry before reinstalling them. When they’re dry and ready to go, reinstall the filters, turn on your AC, and see if the airflow is back to normal. If not, you have some more troubleshooting to do. 

Even if the airflow is normal, you should check and clean your air filters every month or more often if necessary. 

Damaged Fan Motor 

If you remember from our lesson above, the fan motor is responsible for blowing chilled air through your duct system and out the vents. If something happens to the motor and becomes damaged, it won’t be operating at total capacity. The result is that it won’t have enough power to blow air to the far vents in your RV, and you’ll notice reduced airflow. 

How to Fix a Damaged Fan Motor

Unfortunately, fan motors are difficult to troubleshoot and repair. There could be an electrical issue, faulty wiring, a worn belt, or a stuck wheel causing your fan motor to act up. Unless you have HVAC or electrical experience, this is a job best left to the professionals. 

Dirty Coils 

The evaporator coils in your air conditioner are the components turning lukewarm air into cold air. They have refrigerant running through them that effectively turns them into somewhat of a freezer. When air runs over the coils, it gets icy before the fan motor blows it into your RV. 

However, because these coils are located on your RV’s roof, dirt and debris can get on top of them. They will also get dirty if your air filter is dirty and can no longer clean the air flowing through it. Either way, the result is that your evaporator coils get dirty and start to block the air passing over them. 

How to Fix Dirty Coils

  1. First, turn off your air conditioner. 
  2. Next, go onto your RV’s roof and remove the protective shroud that’s covering your air conditioner. 
  3. Take a garden hose and spray water over the top of the evaporator coils. 
  4. Try to angle the hose either up or down, so you’re not spraying straight onto the coils. 
  5. Once you’re satisfied that the coils are clean, put the shroud back onto the AC. 
  6. Turn on the air conditioner and see if the problem is fixed. 
  7. You should clean your evaporator coils in this manner at least once per year if you’re a full-time RVer. 

Your Ducts are Damaged 

Another possible explanation for poor airflow out of your vent or vents is that they’re damaged. The ductwork above the ceiling of your RV is similar to that of a house. There will either be individual ducts running to your vents, or they will all get cut into the main trunk line that runs the length of your RV. 

If you have individual ducts going to each vent, one of them may have become damaged. This can happen during installation or while you’re driving down the road and something in your ceiling falls on top of the vent. 

How to Fix Damage Ducts

Damaged air vents are rare but very possible. If there’s poor airflow out of only one vent, and it’s not the one furthest away from the air conditioner, it’s likely damaged or blocked. The only way to fix this issue is to remove the ceiling around the vent with poor airflow and inspect the ductwork that attaches to it. If it’s damaged, replace the duct with a new one, or try to repair the existing one. 

Blockage in Your Vents 

In the same way that air vents can get damaged, they can also get blocked. Once again, this is a rare problem, but it can still happen. The best way to know if your vent is blocked is to remove the register in question and use your phone to take a picture of the inside of the vent. They’re usually too small to poke your head inside, so a picture will have to do. 

Blockages or damage should be evident from a few pictures, and you can proceed accordingly. 

How to Fix a Blockage in Your Vents

The only way to fix a blocked air vent is to locate the blockage and remove it. This might be more work than it’s worth, and you choose instead to live with uneven airflow in your RV. 

Sheer Distance of the Vent 

It’s important to realize that the fan motor in your air conditioner has limited power. As such, the vents closest to the air conditioner will receive more air than those far away. If low airflow is only present at vents far away from the air conditioner, it’s likely because the motor isn’t strong enough to blow air that far. 

How to Fix the Vent Distance Problem

Your first instinct is probably to replace the motor with a bigger one. However, this isn’t a good idea because it could cause damage to the air conditioner. Your system is designed to produce and disperse a certain amount of air, and trying to blow more air than what’s available could cause issues. A better option is to close or block vents that are getting the most air to redirect it to ducts that are getting less. 

For example, if your bedroom is on the other side of your bathroom and it’s also the farthest vent from your air conditioner, you can block the bathroom vent. As a result, your bedroom will start getting all the air meant for both the bedroom and bathroom. 

Frequently Asked Questions about RV Air Conditioners

Here are some questions about RV air conditioners that you might want the answer to as well.

Why is my RV AC blowing so weak?

Check your air filter to make sure it is clean. This is the most common cause of weak airflow from your air conditioner.

How strong should air come out of my RV AC?

Air should come out of your vents enough to move your hair around and allow you to feel a good breeze.

RV AC Not Blowing Hard Out All Vents – Final Thoughts 

As you can see, there are many things that could be causing your lack of airflow. The best way to get to the bottom of your issue is to start with the easiest fix and proceed to the most involved one. Your air filters and evaporator coil are the most common culprits, with fan motor issues and damaged ductwork being the less likely explanations. 

No matter what’s causing the issue, it’s essential to get to the bottom of it. Insufficient airflow out of your vents while your air conditioner is running at full capacity isn’t just uncomfortable; it’s also dangerous for your air conditioner. A lack of airflow can cause your air conditioner to become overworked and ice over, potentially causing damage to it. Therefore, getting to the root of your airflow problem is vital both for your benefit and that of your air conditioner. 

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2 thoughts on “RV AC Not Blowing Hard Out All Vents: Causes and Fixes”

  1. Tammy Prince

    why does my RV A/C system blow cold air out the return filtered vent and not through the supply vents in my camper?????

    1. Jessica Lauren Vine

      Hey, Tammy.

      I’m sorry you’re dealing with this AC problem. 🙁

      Please try this:

      1. Take the AC grill off and check out the partition that goes between the return and the supply to check if it is sealed or not.

      2. See if the ducts that connect to the plenum A/C discharge are sealed but open to the ducting.

      3. Take a picture looking into the ducts to make sure nothing is crushed or blocked in there.

      4. Take out some of the registers and see if they’re sealed to the ducts. Get more photos looking both ways down the ducts to get more visual help. Once you get to the end register, take a picture looking toward the terminal end of the duct to see if it is sealed. You want to make sure it isn’t leaking out air into the ceiling.

      You should find something amiss there and be able to fix it. If things still aren’t to your liking, you can order some adjustable registers so you can direct the air or stop the airflow in that certain area of the RV.

      I hope this helps!

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