Symptoms Of Not Enough Return Air

Posted by: Mas Broto
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Symptoms Of Not Enough Return Air

Airflow problems are one of the most common problems with an HVAC system. If you think your HVAC system isn’t working right, you may notice one or more of the following symptoms of not enough return air.

There are many things that can cause not enough return air, like dirty filters or leaking ducts. Some are easy to fix, but others need the help of a professional.

Most air conditioners will give you warning signs if there is a problem with the airflow. You might start to have hot and cold spots in your house or no air coming out of the vents. You might get little to no air from the vents, or the air pressure in your home might be off. So, you need to know about these signs to figure out what’s going on.

  1. There are hot and cold spots all over your space. This is often one of the first signs of a problem with the not enough return airflow.
  2. Pressure imbalance. Do you have doors that close on their own, strange whistling sounds, or cold spots? These are signs of problems with air pressure caused by HVAC systems that don’t move enough air.
  3. No air is coming out of vents in your home, or the air coming out is weak or moving slowly.
  4. The problem could be everywhere, or it could just be one AC vent in one room that isn’t blowing air. At this point, you start to notice that something is wrong.
  5. Your AC system blows warm air.

Causes Of Not Enough Return Air Problems And How To Fix Them

Let’s look at some of the most common causes of not enough return air problems in HVAC systems and how to avoid or fix them.

1. Clogged Air Filters.

If you haven’t taken care of your AC in a long time, dirty air filters could be the cause of not enough return air. The air filters in your home are in charge of keeping the air clean. They remove mold, pollen, dust, pet hair, and other pollutants from the air.

For them to work well, you may need to clean them once a month, depending on how often you use them. If they are full of dust and dirt, they can block the airflow and leave your home with weak airflow or hot and cold spots. If you don’t take care of your AC for too long, dirty filters can even stop it from working.

To fix the not enough return air problem, you need to change the air filters. You should clean and change them at least once every three to four months, or more often if you live in a humid area or a place with a lot of pollution.

2. Oversized & Undersized HVAC Unit.

If you bought an air conditioner that was too big because you thought it would cool better because it was bigger, you were wrong. A bigger-than-needed unit has short cycles, which means it turns on and off often.

These cause more wear and tear, and your air conditioner won’t be able to move enough air. Also, it doesn’t run long enough to get rid of all the extra moisture in your home.

In the same way, an HVAC unit that is too small has to work harder to cool your home, which can cause its parts, especially the capacitor, to get too hot.

3. The outdoor unit is getting full of trash.

Leaves are small pieces of trash that can easily get stuck in the outdoor unit of your air conditioner, especially if you use shrubs or other plants to hide or cover them. It will have to work harder to get rid of the heat, which could affect how well your air conditioner moves air.

Your system can also get too hot if the airflow isn’t strong enough. If you want to avoid this problem in the future, it would be best to clean regularly.

4. Your air conditioner has low refrigerant.

If there isn’t enough refrigerant in your HVAC system, it won’t cool the air as well as it should. When there aren’t enough refrigerants, there won’t be much or any air coming out of the vents in the house, and the house won’t cool as well.

Most of the time, your air conditioner doesn’t have enough refrigerant because it is leaking. Your AC coil can leak through cracks and holes. This problem can also be caused by a buildup of corrosion in an AC that hasn’t been taken care of.

5. Ducts that are clogged or leaky.

The ductwork in your AC is what sends cool air to the rest of your home. Dust and other things can get into your ductwork over time if you don’t keep it clean. It can also get holes and cracks that make it harder for air to flow through the HVAC system.

If you live in an old building, birds and rodents may build nests in the ducts, which can make it hard for air to get through. A leaking duct not only causes not enough return air but can also change the quality of the air in your home by sucking in dirt and other pollutants.

6. Vents Blockage.

If you feel like there is not enough return air in your home, it’s most likely because the vents are blocked. You might be blocking your air vents without knowing it. A piece of furniture might be in the way, or you might have closed some vents on a cold day and forgotten to open them again.

This action stops the air from flowing through the HVAC system, which makes you stuffy and uncomfortable in the summer. Vents blockage problem is easy to fix, though. All you have to do is check all the vents in your house and open the ones that are closed or get rid of anything blocking them.

7. Thermostat Won’t Work.

Have you checked everything and still can’t figure out why there is not enough return air? The problem could be your thermostat. It may not seem like there’s a link, but if your thermostat is broken or isn’t calibrated right, it can affect how well your HVAC system moves air.

8. Ductwork that is too big or too small.

Like with the size of the AC, it’s important to think about the size of the ductwork.

If the ductwork is too big, the air pressure won’t be kept up. This will lead to low pressure, and the cool or hot air won’t get where it needs to go. If your ductwork is small, the airflow will be very limited, and the air won’t be able to move around your house evenly, which will make your HVAC airflow weak.

9. The AC fan isn’t working.

Your air conditioner’s blower moves the cold air through the ducts and into your home. Without a strong push from a blower, the airflow in an HVAC system is much less than it could be. If there is too much dust on the blower blades or if the blower motor is broken, the air conditioner won’t move as much air.

To fix the AC fan, use the following guide I have posted here: AC Fan Problems.

10. Dirty Coils.

To cool your home, your HVAC system moves air over the cold evaporator coils. But if they are dirty, they can cause a lot of trouble. When coils are dirty, they can’t release heat, which makes it hard for the air conditioner to work. The unit will have to work harder to cool your space, which can lead to a broken compressor.

If you have never cleaned the coils before, it’s best to let a professional do it. Coil fins are very delicate, and rough cleaning can do a lot of damage to them.


There are many symptoms of not enough return air happen, but almost all of them can be fixed with regular preventive maintenance. If you have any of the above signs of a problem with your HVAC airflow, get your system serviced RIGHT NOW before you get to the last sign, which is a system failure. We hope this helps you diagnose if you indeed have not enough return air.

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Mas Broto

Have been in the heating and air conditioning (HVAC) industry for over 20 years. He is person that will grow and thrive to learn more about the HVAC industry throughout his career. Mas Broto is also a blogger, who's dedicated to bringing you the best knowledge to get ahead in the game of life.

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