Why is My Air Conditioner So Loud? A Florida HVAC tech explains

January 15, 2021

Your air conditioner is a complex piece of equipment, so it’s normal for it to produce some noise as it kicks on. You also may notice a slight humming noise when your AC is running.

However, if your air conditioner is suddenly very loud or is making strange noises you haven’t heard before, there might be a problem.

If your air conditioner is making one of the following noises, it is most likely a sign that something is wrong (or is about to go wrong):

  1. Hissing noise

  2. Rattling noise

  3. Grinding noise

  4. Buzzing noise

  5. Squeaking noise

  6. Rushing or whistling noise

To help you identify and fix the issue, let’s look at each of these noises and provide some answers about what could be causing them.

If you’d like a technician to take a look at your air conditioner, call Advanced Air today to have a professional diagnose the noise and provide a quote for an AC repair.

Noise #1: Hissing noise

If your AC is making a hissing noise, your refrigerant line may have a leak in it.

Refrigerant plays an important role in your air conditioner’s ability to cool your home. Refrigerant is part of a closed-loop system and cycles between your indoor unit to your outdoor unit. Refrigerant absorbs the warmth from the air inside your home, carries that warmth outside and then disperses it into the outdoor air.

However, if you have a leak in your refrigerant line, a hissing noise may be produced when air or refrigerant in its gas phase seeps through the leak.

Other signs you may have a refrigerant leak include:

  • Warmer air coming from your AC vents

  • Increased energy bills

  • AC that’s working longer or tuning on more often than usual

If you think your system may have a refrigerant leak, you’ll need to reach out to a technician who can inspect your AC, repair the leak and recharge your air conditioner. Refrigerant is a toxic substance, so it’s not a repair you can make on your own.

Noise #2: Rattling noise

If your air conditioner is making a rattling noise, it could be caused by one of the following issues:

  • Debris in your outdoor unit: Debris such as sticks, rocks or brush can easily get lodged inside your outdoor AC unit, which can produce a loud rattling noise.

  • A loose part: If the rattling noise is coming from your inside AC unit, there may be a loose part inside that’s rattling around when the unit kicks on.

  • Misaligned or loose fan blades: Your outdoor AC unit has a fan inside it with several blades on it. These fan blades may become misaligned or loose, which can cause a rattling noise. Normal wear and tear over time or improper installation can also cause fan blades to become misaligned.

  • Loose panels: If you recently repaired your AC or hired a technician to do it, one of the panels on your outdoor unit may not have been secured properly after the job was done. Simply tightening any loose screws on the panels may fix the issue.

Generally speaking, if your indoor or outdoor AC unit is making a rattling noise, we recommend calling a technician to diagnose the rattling sound and provide any necessary AC repairs. If a part is damaged or loose, it can cause other parts of your AC to break down as well if it’s not repaired in a timely manner.

Noise #3: Screeching noise

A loud screeching noise is usually a sign that:

  • The compressor is failing

  • A fan blade is misaligned or broken

  • The blower motor is damaged or bad

If the screeching noise is coming from outside…

Your issue is likely a failing compressor or a fan blade.

The compressor is the part of your AC system that pumps refrigerant through the system. If your compressor is starting to go bad, it can make a screeching noise. If your AC is 10+ years old, it’s possible that a faulty compressor is your issue.

Another reason your outdoor unit may be screeching is due to a misaligned fan blade. If a blade is not in its proper position, it can hit the inside of the outdoor unit as it moves, causing a screeching or grinding noise.

If the screeching noise is coming from inside…

Your blower motor is probably wearing out. The blower motor keeps air circulating throughout your system and home. Unfortunately, it’s prone to a lot of wear and tear as a result of all the hard work it does.

Typically, a grinding or screeching noise means your blower motor’s bearings are bad or they need to be lubricated.

A trained technician will be able to diagnose the issue and repair or replace the parts (or your system) for you.

Noise #4: Buzzing noise

Typically, a buzzing noise indicates an electrical issue somewhere within your AC unit.

  • A damaged or loose wire that isn’t correctly connected to your AC’s circuit breaker can sometimes make a buzzing noise.

  • A circuit breaker that does not trip may produce a buzzing noise when there is too much electricity flowing through the wiring.

  • If you hear a buzzing noise when you’re near your outdoor unit, your capacitor may have gone bad. The capacitor is a small cylinder-shaped device inside your outdoor AC unit that stores and supplies electrical energy.

Repairing any electrical issues on your own can be dangerous, so we recommend reaching out to a technician for help if your AC is making a buzzing noise.

Noise #5: Squeaking noise

A squeaking noise may indicate a loose fan belt inside your indoor AC unit.

Newer AC models use direct motors while older ones use blower fan belts. If you have an older AC unit and its fan belt has come off the track or it has frayed due to old age, it may start to make a squeaking noise.

We recommend calling a technician to take a look. They’ll likely realign the fan belt or replace it entirely, depending on the situation.

Noise #6: Rushing or whistling noise

If you hear rushing or whistling noises coming from the vents, your home’s ducts may be poorly designed or undersized.

Undersized ducts or too many sharp angles or bends in the duct design increases air velocity. And high air velocity increases noise. Vents can also become noisy when the duct design pushes too much air through them.

Your ducts may also be the problem if you experience the following things in your home:

  • Stuffy air

  • Mold growth (usually on vents)

  • Doors slamming by themselves

If you think your home may have a faulty duct design, have a technician inspect your air duct system. They’ll be able to determine if you will need a complete redesign or just a quick repair somewhere.

Tired of dealing with a noisy air conditioner? Call Advanced Air

A loud air conditioner can be annoying and may also lead to expensive repairs if it’s not taken care of promptly. If your air conditioner is making strange noises, your best bet is to contact Advanced Air. We are committed to providing round-the-clock, quality service with no strings attached.

Call us today or schedule your AC repair online today.

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