Causes And Signs Of AC Fan Malfunctions

Is your HVAC system struggling to turn on and off? Learn to recognize HVAC problems early so you can avoid permanent damage.

Causes And Signs Of AC Fan Malfunctions

Causes And Signs Of AC Fan Malfunctions

6 March 2023
, Blog

The air conditioner cannot cool your home efficiently if its fan malfunctions. Below are the causes and signs of AC fan malfunction.


Several things can interfere with AC fan functions. Below are examples of such issues.

Electrical Issues

Electrical energy powers the fan's rotation, so electrical problems can cause the fan's malfunction. For example, faulty wiring, damaged capacitor, or motor failure can all lead to fan malfunctions. Consider a fan motor that experiences a short circuit that damages its windings. The motor might not generate enough energy to rotate the fan.

Belt Problems

If a fan belt connects the motor and the fan, as is typically the case, anything that affects the belt will affect the fan. For example, fan belts lose their tension over time, leading to slippage. The belts also experience wear and tear that increases their running friction. Debris accumulation on the belt increases its risk of damage.

Blade Damage

AC fans feature blades with specific aerodynamic designs that reduce drag over the fans and facilitate maximum airflow. The blades' designs ensure the fans can deliver the required air with minimal energy consumption. Damage to the fan's blades interferes with their aerodynamic design and reduces the air they can push through the ductwork.

Debris Blockage

Both large and small debris particles affect the fan's operations. Small debris affects components such as belts and motors. Large debris can block individual fan blades, slow the fan's rotation, or virtually prevent fan movement. Fan blade blockage can even lead to motor damage by forcing the motor to overwork and overheat as it tries to get the fan moving.


You should know if your AC fan malfunctions so you can intervene before the problem affects other AC parts. Below are common signs of fan malfunctions.

Increased Noise

A typical AC emits some noise during normal operations. Increased noise means something is wrong with the AC. For example, damaged fan blades can emit considerable noise if they hit the fan's housing. Increased noise is also possible if the fan motor is overworking due to fan problems.

Inefficient Cooling

The fan pushes air through the ductwork so the air can circulate and cool the house. A compromised fan operation reduces air circulation and cooling efficiency. For example, your supply vents might blow warm instead of cool air due to fan damage.

Increased Energy Bills

Your AC design forces it to cool your house to the required temperature irrespective of the AC's condition. Thus, the AC will strive to meet the desired cooling output even if the fan cannot blow the required air. Unfortunately, an overworking AC consumes more electricity than usual.

Contact a company that offers residential air conditioning servicing to learn more.

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Keeping My HVAC System On Point

About a year ago, I could tell that our HVAC system was really starting to struggle. No matter what we did, the system seemed to have a hard time turning on and off. When our air was running, it smelled terrible. In the winter, it seemed like our home was never warm enough. To ward off sudden failures, we hired a professional to come out and inspect our system. After a thorough analysis, we discovered that there were some serious fan problems. This blog is all about recognizing HVAC system problems early and keeping your system on point, so that you can avoid permanent damage.