Low Airflow: What It Means

If you have noticed that your home is taking far longer to cool or heat, the reason may be restricted or weak airflow. Every air conditioner is a “forced-air” cooling system, while heating systems can be forced-air or radiant. The difference is the fact that a forced-air system relies on cooling or heating the air in your home and sending it through ductwork or equipment to the rooms of your home. Without proper airflow, it becomes nearly impossible for your home to cool down effectively.

As the flow of air diminishes, the air circulates far more slowly, and so it takes longer to achieve the desired temperature. From dirty air filters to leaking ducts, there are many reasons for your air conditioner airflow to be weak. Some are easy to fix, while others require professional help. If airflow issues go untreated, they can result in air conditioner problems such as compressor failure, which is quite expensive to repair. In some cases, you might even have to replace it.

To help you effectively deal with HVAC airflow issues before they get worse, we have prepared a list of the most common causes of low air flow along with some tips to fix them.


Symptoms Of Weak Air Flow In AC

If your HVAC unit is struggling with air flow, you will likely be able to tell by evaluating these symptoms:


1. Hot & Cold Spots

You may feel that certain parts of your house are either cooler or warmer than the rest of it. If you have set your thermostat to the same setting throughout your house, you might be wondering why certain rooms feel hot while others feel cold. Temperature variations in your home are a vital sign, indicating that there is something wrong with your HVAC airflow. If the airflow is adequate, there should be no hot and cold spots.


2. Weak HVAC Airflow from the Vents

If your rooms remain uncomfortable even when the thermostat is set to the lowest setting and you feel little to no air blowing out of the vents, this indicates an airflow problem.


3. Pressure Imbalance

Whistling noises, drafty areas and doors slamming suddenly, all point to the fact that there is an air pressure imbalance. Such imbalances occur when the airflow is restricted.


4.  Blowing Warm Air

When an AC unit starts blowing warm air while it is above 100F outside, you are dealing with a poor HVAC airflow issue that needs to be fixed immediately to avoid further damage.


Why Air Conditioner Airflow Is Weak And How To Fix


  1. Clogged or Dirty Air Filters

Your air conditioner can only put out as much air as it “breathes in” through the return vents. But a clogged, dirty filter limits the amount of air your AC can pull in from your home. The air filters are responsible for keeping the air clean in your home. They filter out mold, pollen, dust, pet dander, and outdoor pollutants. In order to function optimally, they need to be cleaned monthly, depending on your usage.

Imagine trying to breathe with a heavy blanket over your mouth and nose. This struggle to get air in is what a dirty air filter does to your AC. More than half the airflow problems occur because the homeowner forgot to change or clean the air filters in their AC unit.


How To Fix – The solution is simple and inexpensive. Every month change your air filters. You can do this yourself and need not depend on anybody to come and help you out.


  1. Blocked or Broken Air Vents

Air vents represent the final path the air needs to take in order for you to feel comfortable. If you just moved furniture around to improve the look or appeal of your home, then you might have accidentally blocked an air vent. Or, you could have a broken air vent that will not open no matter what you do.


How To Fix – Fixing the problem is as simple as ensuring nothing blocks the air vents and registers. If there is any obstruction, remove it.

In the case of a broken vent, call our team for support.


  1. Leaky or Blocked Ducts

Air passes through the ducts and enters each room in your home. When the ducts get

Ductwork represents the pathway that air needs to take in order for it to properly cool off your home. If there is a gap in a section of your ductwork, the air is going to escape into an area of your home where you cannot feel it, like a crawlspace, the basement, or the attic. Not only does a leaking duct reduce the airflow, but it can also impact your home’s air quality by sucking up dirt and other pollutants.

Make sure you get your ductwork inspected when you think there’s something that might be inhibiting the airflow in your home.


How To Fix – This is a job for professionals. An Aire-Tech expert needs to come and inspect the entire ductwork of your home for any tears and leaks. If they find any, they need to be sealed as soon as possible. Also, get regular maintenance of the HVAC unit done and pay special attention to the fact that your ductwork is given a thorough cleaning.


  1. Slow Fan/Blower Speed

Your AC blower is located inside your air handler (inside unit) and is a very likely culprit when it comes to loss of airflow. It is the “fan” that pushes all the cold air through your ducts and into your house. Without this strong push, airflow would be dramatically reduced.

Some blower issues that restrict airflow include an excessive amount of dust or dirt on the blades or a bad blower motor.


How To Fix – Cleaning the fan and replacing the fan motor should do the trick. However, it is something where you need the help of a trained technician.


  1. Frozen Evaporator Coil

In your air conditioner, there is a component known as the evaporator coil. This coil is responsible for cooling the air. If those coils are frozen over, it basically blocks the air passing over the coils and into your duct system. This blockage results in significantly weaker air flow.

Several things can cause your evaporator coils to freeze over, including:

  • A dirty air filter or blocked return vent
  • Dirt on your evaporator coils
  • A refrigerant leak


How To Fix – Frozen evaporator coils are usually caused by dirty air filters, blocked vents, a faulty motor, and low refrigerant levels. The first two things you can handle yourself. Check your evaporator coils. The first place they will freeze is inside your air handler. Note: Your air handler is usually located in a closet, attic or basement. If you see ice forming on the lines or if they’re already completely frozen over, turn your thermostat fan to “ON” mode instead of “AUTO” to help your refrigerant lines thaw (make sure to place a large plastic tray or Tupperware underneath frozen coils to catch the melting ice).

Check and change your air filter if needed. If the airflow does not improve and your coils still freeze over, have a professional inspect your system for refrigerant leaks. If you have a leak, they will be able to find it, fix it and recharge your system.


  1. Closed Damper Valve

Dampers are among the primary flow regulators in your heating and cooling system. They can direct airflow or completely put a stop to it, so if an area in your home needs more air, dampers can block off or open paths that will make it easier for the air to reach the space.


How To Fix – The dampers can be automatically controlled by your thermostat. If you do have an automatic damper system, you might want to check to see if the dampers are stuck. However, this might be more of an electrical problem. Since the thermostat will continue to change the position of the dampers automatically, it would be too much of a hassle to manually adjust them.

In the case of manual dampers, the problem could be as simple as being unintentionally left in the wrong position. You can check if they’re in the correct position by locating them in your ductwork.


How to Improve HVAC Airflow

You know how frustrating it can be when your HVAC airflow is not up to the mark on a hot summer day. This not only impacts the comfort level but can also cost you high bills as your system is working harder to achieve the set temperature.

Here are some simple ways to improve weak air conditioner airflow:

  • Clean your air filters regularly
  • Check your AC vents to see if they are obstructed in any way and remove any blockage you find
  • Fix any leaks and holes in your HVAC ductwork
  • Clean your fan blades regularly with a soft cloth
  • Schedule regular AC tune-ups to help your unit run smoothly

Final Thoughts

Weak airflow can be a sign of your AC system developing problems, so with regular tune-ups, an expert can find out the issue before it gets worse. As cold weather approaches, it is important to take a few preventative measures to protect your home through the chilly months. Winterizing is generally a task that can be done relatively inexpensively but will make a big difference in how comfortable your home is and could end up saving you money on energy bills, too. In fact, many very effective home weatherproofing jobs are something that homeowners can complete without professional help.

If your system needs repair or inspection before winter, call us on 951-926-1002. You can also visit our Contact page and complete the contact form.