Why Does My AC Have Low Airflow?

Weak AC Airflow

By Hannah Brennan

Low airflow from your air conditioner can be an indication of a larger issue. But, there are multiple reasons low airflow could be affecting your home. 

If only one of your vents is producing low airflow, it might be from one of these 3 reasons:

1. Crushed duct flex → Flex ducts are flexible wire tubes covered in plastic used in many homes. Due to their flexibility, they are easily crushed and thus restrict airflow to an area of your home.
2. Disconnected air duct → Metal sheet ductwork and flex ducts can become disconnected or develop leaks over time. According to Energy Star, a house on average loses 20-30% of the air that moves through the duct system because of disconnection or leaks.
3. Closed damper → Dampers are valves from your duct system that block or restrict airflow to a room. However, if they accidentally become closed, they will restrict the airflow through a particular vent.

If 2 or more of your vents have low airflow, here are 5 possible reasons as to why:

1. Blockage and build ups → Dust and dirt builds up on your air filters and can clog spots in your ducts. This can spread throughout the air in your home and overall reduce the air flow throughout your residence.
2. Fan motor → There could be an internal problem with your fan motor, like faulty electrical wiring, causing the fan to turn more slowly. Moreover, any issue regarding your air conditioner’s fan motor is a serious repair in need of a professional.
3. Bent fan blades → Individual fan blades can bend and be inoperable. Additionally, the fan blades can become misaligned. A foreign object like a twig or screw could be jamming the mechanism, causing the low air flow.
4. Frozen evaporator coil → Cold evaporator coils provide cool air from your air conditioner. However, these coils can become frozen over and block the air passing over the coils in the ductwork.
5. Blocked/Undersized return vents → If there is an object in front of your return vent, your residence isn’t filtering out air. In addition, if your return vents are too small for circulation needs, it lowers airflow.

If you have low airflow in your home, call us or schedule an appointment with one of our licensed HVAC technicians to diagnose the problem.

Remember to regularly change your air filters to keep steady air flow in your residence. Learn more about your HVAC air filters in our blog here.