How To Fix A Noisy Air Conditioner
Written By: Alexis Bennett
Edited by: Andrew Dunn
Are you looking for ways to fix a noisy air conditioner? If so, you are in luck.
In this guide, you will learn:
- What causes your air conditioner to make loud noises?
- How do you troubleshoot a noisy air conditioner?
- Can you prevent your air conditioner from making noise?
- Is a loud AC unit dangerous?
- And more!
A noisy air conditioner can be a real pain. From loud banging to a high-pitched screeching, HVAC sounds cause alarm in even the calmest homeowners.
As the sound keeps you up at night, you can’t help but wonder if your air conditioner will keep chugging along or if you will wake up sweating in the morning because it finally gave up.
If you have spent too many nights this way, read through these DIY tips to identify and fix the source of your noisy air conditioner.
What's In This Guide?
What Makes Your Air Conditioner Noisy?
There are many parts malfunctions that can make your air conditioner sound bad, but air conditioners can be loud even when operating optimally. If your unit sounds strange, it could be:
- A bad run capacitor
- A failing fan motor
- A refrigerant leak
- Bent fan blades
- A bad air compressor
- A bad blower
- A clogged, dirty, or missing air filter
- Dirty condenser coils
Those are just the most common causes of air conditioner noise. There are some less common causes, as well. Diagnosing the source can be challenging, but it is well worth your effort.
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What Do Common Air Conditioner Sounds Indicate?
The way your air conditioner sounds can help you identify the problem. There are some of these problems that are more easily identifiable than others. Here is a list of the most common sounds your air conditioner may make.
Squeaking Or Squealing Noise
When you hear a squealing sound from your outside unit, it may indicate that you need to replace the run capacitor, or there could be something preventing the fan from turning on.
If your condenser fan is off-center or one of the fan blades is bent, it can also make a squeaking noise. 
Buzzing And Rattling
Electrical breakdowns can cause buzzing noises. There are several parts in both the outdoor unit and inside the unit that may buzz if there is a voltage problem.
Buzzing and rattling can also indicate that there are loose screws. When your air conditioner is running, your HVAC system‘s vibration can loosen parts and cause them to make noises that you did not hear before.
Banging Noise
Sometimes, central air conditioners make a loud banging or slamming sound when they shut off. The sound can be the result of airflow and pressure in the ductwork causing the air damper to slam shut when your system powers down.
A loose air filter hitting the return grille, loose fan in the air handler, debris in the outdoor unit, and loose parts hitting each other can all cause loud slamming sounds.
How Do You Troubleshoot AC Noise?
The best way to troubleshoot your air conditioner is to perform maintenance tasks that should help extend your system’s life anyway. So, follow these steps to remedy your AC banging, slamming, buzzing, squealing, or rattling noise.
Replace Your Air Filters
Air filters are an important part of your HVAC system. Not only do filters remove dust and other dangerous particles from your home. They also protect key air conditioner components like your blower motor and evaporator coil from buildup that can cause your system to breakdown prematurely.
If you run your air conditioning system with a filthy filter, it can obstruct airflow and cause your system to freeze or overheat. A clean air filter is so vital that most AC repair technicians change it before they start checking over the rest of your system.
Clean Your Coils
There is a condenser coil in your outside air conditioning unit and an evaporator coil in the indoor air handler. While a dirty coil usually doesn’t make any noise, it can cause other parts to fail.
If sticks or other debris are in the outside unit, the fan may make a strange sound as the blade spins. Before your clean your coils, you should shut the power off to your air conditioner.
There should be a switch net next to your outside air conditioner unit, as well. You should always turn the power off at the switch to ensure that your air condenser does not turn on while you are working on it.
Once the power is off, remove any weeds or leaves around the machine. Then, carefully unscrew the top grille.
With the grille removed, clean out anything that is around the outdoor fan. After you have all of the debris removed, use a coil cleaner to remove the buildup.
Once you clean your coil, use a fin comb to straighten any bent fins and let them dry completely before using your system.
For more information on cleaning your air conditioner coils, check out this video:
Check For Loose Parts
You can check your air conditioner for loose parts. It should be fairly straightforward to locate loose parts.
Follow the sound to locate the loose parts. Then, tighten any bolts, nuts, or screws that are loose.
Check For Refrigerant Leaks
Refrigerant escaping your system often makes a hissing sound. You do not have the tools necessary to check your refrigerant levels.
You can check for ice on the condenser unit, refrigerant lines. and evaporator coil. If your system is low on coolant, you will likely see ice on your air conditioner.
If you see frost on your air conditioner, you will need to contact an HVAC technician to check for leaks.
Final Advice On How To Fix A Noisy Air Conditioner
There are many air conditioning problems you can fix on your own, but hiring a professional air conditioner repair technician gives you peace of mind. That peace of mind comes at a cost.
Air conditioning specialists charge between $50 and $150 an hour. Even if the part is affordable, the labor can break your budget.
A home warranty plan is one of the best ways to prepare for major and minor air conditioning trouble. With a high-quality service contract, you do not have to worry about self-diagnosing or attempting DIY fixes.
