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12 Common HVAC Airflow Problems, Causes & How to Fix Them

Are you facing an airflow issue in some room of your house? If yes, then this may be a problem with your HVAC airflow. You can quickly identify the problem by testing airflow in a different room if you notice one room is cooler or warmer than the other one when the airflow settings are some, then definitely there is a problem with your HVAC airflow, and you need to fix it immediately.

In this condition, you first change the AC setting and check if there is any difference, then directly put your hands in front of the AC vents and check whether the airflow exists or not. In both conditions, if you are not feeling the air or feel weak airflow, you may experience air draft in your house. There are many causes and reasons behind the HVAC airflow problem, and it will be challenging to identify the problem and its root cause if you’re not a professional.

Some HVAC airflow problems can be identified and fixed at home, but generally, we call a nearby professional for repair. To help you identify the HVAC problem at home, we have written this guide that explains 12 different HVAC airflow problems, their causes, and how you can fix them.

12 Causes of HVAC Airflow Problems & Their Solutions

You are making a big mistake if you are not fixing the airflow even after identifying it. It can result in compressor failure even in some cases; you need to replace your entire cooling or heating unit. By reading the below shared common problem of HVAC system and its causes, you can effectively deal with the issue.

1. Blocked Vents & Register

The HVAC system vents or registers are defiantly blocked if your room temperature is not changing or your room is not cool or hot as before, even when the HVAC system is running. Many people have been facing issues because of blocking the AC vents and they call professionals without checking the HVAC system.

You should ensure that nothing is blocking the cooling or heating system; if any furniture or other household item is blocking the airflow, then you will not feel the change in room temperature; even if the HVAC system is working at its best, the circulation of the air is more important then anything. 

When calling the professional, you should also check that the vents are opened or not. Users often accidentally close the system vents, and without checking, they think the problem is with the system.

2. Larger HVAC Unit Than Required

Many people think that purchasing an HVAC unit of enormous capacity will provide them with efficient cooling, but this is not true. HVAC systems are made with intelligent technology; they will turn off automatically when they reach the desired temperature. Because of that, the more extensive system will cool or heat the room quickly and turn OFF automatically or turn on when the temperature is down; it turns ON automatically. 

Those frequent turns OFF & ON will disturb the system, and the system will not be able to provide you with adequate airflow. Even the more powerful system will not run long to remove moisture from your room. You can use the HVAC Load Calculator and HVAC Home Auditor to calculate the heat loss/gain quickly and choose the right HVAC system for your house.

3. Clogged Filters

Filters in your HVAC system play an important role; they are responsible for removing debris and dust from the air and keeping it away from the air blower and ducts. When your HVAC system filter is overloaded or clogged after prolonged use, you will not get sufficient airflow from your cooling or heating system, resulting in the stuffy air.

A clogged filter will not just disturb the airflow, but it will also permanently damage other parts of the system, make sure you change the filters as advised by the system manufacturers.

4. Blocked or Leaky Ducts

This is what happens when you ignore the sign of clogged filters. If you do not change the air filter on time, then all the dust which gets past will accumulate in your duct and create a new problem. It will also result in a lack of airflow; especially the narrow ducts can be clogged easily.

Even with the year of use, duct walls can also develop cracks due to rusting or anything else from where the air leaks. Recommending you scrutinize your duct and clean it to solve to problem from the root.

5. Dirty Coils

The coil is the main compound of any HVAC system. All the air must be passed over the cold evaporator coil to cool your place effectively. When the coils are dirty, the heat will not be released from the air, resulting in a lack of colling, and your HVAC unit also needs to work hard to cool, which may also result in compressor failure. 

Do not clean your coils at home. If you have not done it before, you should hire a professional for the job; the fins of the coil are sensitive, and harsh cleaning can also damage it.

6. Less Number of Return Air Vents

The return air vents are equally important compared to any other system compound. The equal amount of the air should be reconditioned and redistributed to the cool air circulated in the hour by the HVAC unit. If your place does not have a sufficient amount of return air vents, then not only will you feel congested, but it will also affect the working of the HVAC unit, and your unit will receive less airflow.

To solve the problem, you need to increase the number of return air vents.

7. AC Blower Not Working

AC Blower is responsible for the strong airflow. It pushes the cold air through the long duct to your room. If your HVAC system’s air blower stops working, you can easily identify it by putting your hand in front of the AC vents. If you are not feeling the air strongly, then it can be a problem with the AC blower.

Dust on the blower fan may also reduce the airflow. To fix it, you need to check whether your AC blower fan is working or not. If it is working, then clean it carefully, remove all the dirt from the blades, and your problem will be resolved.

8. Oversized & Undersized Ductwork

The size of the ductwork is also responsible for airflow. If the duct is bigger than your HVAC unit requires, it will not maintain the desired pressure. In the case of a small duct, the air pressure is heavily restricted and will not evenly distribute in all rooms, and you feel different airflow in a different room of your home.

And the only solution to this problem is to replace the entire duct.

9. Low Refrigerant Levels in Your Unit

The low level of refrigerants is also responsible for low or no airflow from the vents, affecting the cooling of your house. Refrigerants level can be down because of leakage; there may be a hole or crake in the coil of your system.

If your system’s maintenance is improper, then the corrosion on the inner parts can also lead to this issue. To refill the refrigerants, you need to call the professional and make sure to refill the refrigerants as advised by the HVAC unit manufacturers.

10. The Assemblage of Trash in the Outdoor Unit

Most people put their HVAC outdoor unit in the garden, and sometimes the branches of plants hide or cover the outdoor unit completely. You should check if anything is covering your outdoor unit, and then you should clean it instantly.

It does not just affect the airflow but also overheats your HVAC system. You should regularly clean the outdoor unit.

11. Faulty Thermostat

The problem with your thermostat can also be the reason behind the problem. If you have checked all the things mentioned above but are still unable to find out the problem, then it’s time to check the thermostat. 

First, check your thermostat’s battery, replace the batteries if required, and then recheck it. If there is still no improvement, you need to clean it from the inside. Open the cover and clean all the dust; you can use a brush to clean it gently. 

12. Old HVAC Unit

The life of an HVAC unit is up to 10 to 15 years. If your HVAC unit is older and you notice a significant decrease in the airflow, it’s time to change it. You should check with the HVAC technicians who can help you find accurate heat loss/heat gain of your place with HVAC software before you purchase a new unit. You should also ask HVAC professional to do home energy efficiency audit to create a customized energy profile.

Why Should You Fix Air Flow Problem As Soon As Possible?

We have often seen many people neglect the heating or cooling system problem in their house, but I can say you, ignoring those problems will cost you more in the future than repairing them now. If you do not fix the airflow problem, it will damage your HVAC system, and you need to replace it. Repairing the system quickly will improve the air quality, and your system will last a long time. 

It is also essential that you breathe clean air. It becomes more important if you are surfing from any respiratory condition or allergies. With the help of the above shared 12 common problems and their fixes, you can try to fix your system without calling a professional.