Banging, buzzing, squealing, hissing, clicking — if your air conditioner is making any of these sounds, it could be more than an annoyance. You may be wondering, "why is my air conditioner making noise?" Read on to get some answers.
To help you determine the cause of your air conditioner sound (and how to fix it), we've put together a list of the most common sounds. We share what air conditioner sounds mean, how to fix them, and when they may indicate a more serious problem.
Common Air Conditioner Sounds and What They Mean
What's the difference between whistling and whirring? What does it mean when your air conditioner sounds like a jet engine? We cover these questions and other common AC noises. Different noises correspond to different issues and having a basic understanding of what they mean can help you communicate the problem to experts — or even fix it yourself.
Knocking
Air conditioner rattling noises or knocking sounds can be a sign of a loose or broken component like a piston pin, connecting rod, or crankshaft that has made its way into the compressor. It can also be a sign of a failing air compressor. Diagnosing an AC compressor noise is likely a job for a professional, so it could be time to schedule a tune-up or inspection by an AC technician.
Clicking
AC clicking sounds at the beginning or end of a cooling cycle can be normal, but if you're hearing constant clicking, there's likely an issue with your system. Clicking noises can indicate a faulty thermostat, issues with electrical components, or a fan obstruction. You can check your outdoor AC unit for obstructions by turning off the unit and checking the fan, but if you don't find anything, it's time to contact an HVAC pro for an inspection or tune-up.
Whistling
Whistling noises from your AC can be a sign of leaking refrigerant but can also point to less serious issues like blocked vents or an old air filter. AC screaming or screeching sounds can also indicate a buildup of pressure in your air compressor. Both situations require attention from a professional, so it could be time for an AC inspection or tune-up from your local HVAC professionals.
Pro tip: If your home warranty includes HVAC coverage, contact your home warranty company when your system breaks down, and they'll assign a service technician to help.
Rattling
Air conditioner rattling sounds can be a sign of imbalanced or loose parts. If your AC is making a clanking noise, you may be dealing with a broken piece hitting other parts. It could also be a sign that your outdoor blower or fan is askew and needs to be repaired or rebalanced. Clanking or rattling noises from AC units typically do not resolve on their own, so it's a good idea to call the professionals for AC maintenance or a tune-up.
Regularly scheduled maintenance and inspections can help prevent these problems, and if you tackle them right away, they'll likely be simple for professionals to fix.
Humming
If your air conditioner is making a humming noise, refrigerant piping or another loose part may be vibrating within the unit. Are you hearing humming sounds from an outside AC unit? This could indicate an electrical problem like a wiring or motor issue. If your AC fan is not spinning, you could also be dealing with an electrical problem. Time to call an HVAC professional to get the issue fixed.
Buzzing
Whether your AC unit is buzzing every few minutes or you're experiencing a constant noise, this sound can indicate many possible issues:
- Imbalanced or loose fan parts
- Motor problems
- Coolant lines rubbing
- Debris in your unit or condenser coil
- Low coolant levels
- Dirty air filters
You may be able to resolve a buzzing noise on your own by replacing your air filter or cleaning your unit, but if the problem persists, it's probably time for a system tune-up.
Whooshing
If your air conditioner makes a whooshing noise, it's often a sign that it's on and blowing air through the vents as intended. If you have a heat pump and it's whooshing during the winter, the heat pump is pulling heat from the outside air to bring into your home. When it's below freezing outside, this process may create a buildup of ice. Your heat pump will then move to defrost mode, blowing air over the heat exchange to defrost it and leading to a whooshing noise. Typically, whooshing sounds do not indicate a problem with your HVAC system.
Read more: How do air conditioners work?
Whirring
If your AC is whirring or spinning, the noise may indicate a blower or motor malfunction. Faulty bearings, broken or loose fan blades or a worn-out belt may be to blame — but the issue could also be as simple as debris stuck in your indoor fan or outdoor unit. If you can see visible debris causing the noise, remove it by cleaning your HVAC unit. Can't see the source of the problem? Time to schedule maintenance with an AC professional.
How to Fix Common AC Noises
While your AC making a loud noise isn't always a sign of a serious problem, the best course of action is often to schedule maintenance or a tune-up. However, there are some safe DIY repairs you can try. Here's how to quiet a noisy air conditioner:
Tighten Screws
Vibration caused by the everyday use of your AC can cause screws to loosen over time. Those loose screws can rattle around, and lead to other more important components detaching over time. You can tighten visible screws yourself and have them tightened during routine tune-ups or maintenance.
Clear Debris
If your outside AC unit is making loud noises, you can try hosing it off and scrubbing the exterior with a brush to remove obvious debris. This will help keep air moving through the unit smoothly and quietly. You can also clean your indoor air return vent by removing the cover and vacuuming inside the register to help keep filters fresh longer and avoid your AC making buzzing noises.
During your regular tune-up or maintenance appointments, ask your technician to remove debris inside your unit to prevent future clanging, banging, rattling, or other unpleasant noises.
Straighten and Clean Coil Fins
Maintaining the coil fins inside your unit can increase its efficiency and prevent coolant leaks (which can lead to many of the noises mentioned above). When you have your next HVAC tune-up, the technician can inspect the AC system for any potential issues to keep your unit in optimal shape.
FAQs about HVAC Noises
How Long Do AC Systems Last?
Air conditioning units typically last 10-15 years. Heating systems can last slightly longer — between 10-20 years if well maintained. If you notice your heating or cooling system working less efficiently or the temperature in your home fluctuating unexpectedly, it may be time for an HVAC tune-up appointment.
Do Home Warranties Cover Air Conditioners?
First American Home Warranty can help protect your budget from expensive AC repair and replacement costs with our home warranty plans. With AC coverage on your First American home warranty plan, you have a solution at your fingertips when your air conditioning system breaks. We also offer HVAC tune-up coverage to keep your system working efficiently.
Get a free home warranty quote today.
The contents of this article are provided for general guidance only. First American Home Warranty does not assume any responsibility for losses or damages as a result of using this information.
