Why Does My Air Conditioner Make a Whooshing Noise?

Unusual air conditioning noises often serve as early indicators of underlying issues. Among these, a distinctive whooshing sound stands out – an audible sign that something within the system might be amiss. Keep reading as HVAC.com, your trusted expert for heating, cooling, and indoor air quality advice, explores the potential causes, significance, and fixes to address why an air conditioner makes a whooshing noise.

Common Causes of a Whooshing Air Conditioner

A properly functioning air conditioning system should make very little noise, aside from the sound of starting or ending a cycle, or the gentle hum while it operates. Any noises out of the ordinary, such as an AC whooshing sound, should be inspected by a professional HVAC technician.

Unfortunately, a simple explanation isn’t available for why air conditioners make whooshing noises, as several issues can be at play, including:

1. Airflow Issues

Restricted or improper airflow from your central air conditioner can cause a whooshing sound. This can be a simple fix if the problem is a clogged or dirty air filter; simply replace it with a new filter. If the noise persists, however, a more serious underlying issue could be at play such as an aging and inefficient system that may need to be replaced.

2. Ductwork Problems

Your ductwork transports conditioned air from your central HVAC system to your home’s living areas to provide heating and cooling. Over time, issues such as cracks and leaks can develop that lead to a loss of airflow. Leaking, damaged, or loose air ducts can create an air conditioner whooshing noise as air moves through the system.

3. Blocked Vents

A blocked vent can also cause a whooshing sound from an air conditioner. “This sound usually comes from blocked vents,” said Skyler Christensen, owner of Beehive Plumbing in the Salt Lake City, UT, area. “When one of the AC’s supply vents is blocked, the air rushes through the other with more pressure. This excessive airflow through the AC’s ducts causes a whooshing sound.”

4. Blower Fan Issues

A malfunctioning blower fan, located in the indoor air handling unit, can result in irregular airflow and noises if the blades are misaligned, damaged, or clogged.

5. Damaged Fan Motor

The fan motor that propels air through the system could be damaged or worn out, resulting in unusual noises such as an AC making a whooshing sound.

6. Dirty Evaporator Coils

The air conditioning system’s evaporator coil is tasked with pulling heat and excess humidity from the air. Due to a lack of AC maintenance, the evaporator coil can collect dust, dirt, and other debris that can disrupt airflow. This can cause noises such as whooshing when air passes over the coils. A frozen evaporator coil can also create whooshing noises as air passes through.

7. Refrigerant Issues

Issues within the refrigerant lines such as low refrigerant levels, a leak, or a restriction can make a whooshing sound as the refrigerant travels through the system.

8. Normal Operation

A gentle whooshing sound may be part of the AC unit’s normal operation and not something to worry about. This could include the light sound of air moving through the ducts or the movement of refrigerant through the system.

What to Do If Your Air Conditioner Makes a Whooshing Noise?

If your air conditioning system makes a loud whooshing noise or another noise such as AC grinding, consider taking the following actions:

• Check the condition of the air filter. Air filters should be replaced about every two months to ensure a healthy indoor air supply and efficient airflow. Replace the filter if it’s clogged or dirty.
• Inspect the ductwork. Check the ductwork for any signs of damage or leaks. You can use an incense stick or smoke pencil to check for leaks. If smoke is being blown around, there may be a leak.
• Perform regular AC maintenance. Ensure regular maintenance is performed on your AC unit. A yearly maintenance checkup each spring allows a technician to inspect and clean all necessary components and catch issues that could lead to noise.
• Contact a professional HVAC technician. If changing the filter or checking the ductwork doesn’t eliminate the whooshing sound, contact a qualified HVAC technician. They can diagnose the specific problem and make the appropriate repair.

“Remember that some AC noises are normal, while others can indicate significant problems,” said Dave Roebel, owner of Northeast Mechanical Services in Northeast Indiana. “If in doubt, it’s always safer to consult a professional rather than trying to troubleshoot complex issues on your own.”