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hearing strange noises

Strange Air Conditioning Sounds You Shouldn’t Ignore

Strange Air Conditioning Sounds You Shouldn’t Ignore


Hot and humid Missouri summers require an air conditioner.  They work overtime during the summer months. Then, once the cold comes, they lie in wait for months on end.

All of this can lead to malfunction. The first clues of a major air conditioner malfunction are air conditioning sounds (strange sounds) coming from your system.  That's when you need AC repair services by an HVAC professional.

Here we will let you know the sounds that a normal system makes. We also give you the list of the most concerning air conditioning sounds you should not ignore.  Read on to find out more.

Table of Contents

Normal Air Conditioning Sounds

All air conditioners make various noises. Here are some of the air conditioning sounds you can expect from a healthy AC system.

Plane Launching Noise

Air Conditioning Sounds like plane

If your air conditioner sounds like a jet engine at start-up, you have nothing to worry about. Air conditioning sounds during system startups include rattling, some clicking, and a woosh from the initial air burst from the system. These air conditioning sounds are normal and you should hear the same types of sounds every time your unit kicks on.

Whooshing Noise

If your air conditioner makes whooshing a noise, that’s also not a problem. You will always hear light and gentle whooshing noises when your AC is on. There's air moving through there that makes a sound. This will get louder as you walk under vents. This should sound normal and not be alarming.

Soft Clicking Sounds

Once you reach the ideal home temperature, you'll hear some clicks. These are signaling the system is powering down until it's needed again. Depending on the temperature of your thermostat, this could happen many times in a day.

Air Conditioning Sounds That Usually Indicate a Problem

Now onto the crucial noises, the weird ones you shouldn't ignore.

AC Popping Sound

If your air conditioner is making loud popping noises, it's probably not your AC. Popping can be a sign of shoddy ductwork. The air conditioner popping noise occurs when the system kicks on and off. When the air rushes into or out of the ductwork, popping at the joints can start.

While this can be annoying and lower your AC efficiency, it won't blow your system up. However, it would be a good idea to get your ducts inspected during regular HVAC maintenance.

Repairing your ductwork will allow your AC system to work at its total capacity without burning unnecessary energy.

While you're at it, make sure that your insulation is up to snuff. Between solid ducts and thick insulation, you'll have a powerful AC that can keep the temperature even with much smaller bursts of energy.

AC Clicking Sound

Air conditioning sounds that should concern you are extra clicking at startup. Pay attention to the startup noises of your unit. Are they changing? Are there more clicks? Does the clicking go on before the system comes to life?

These are clues that you may have a problem with your air conditioner capacitor. The capacitor starts the motor running when your system powers up. Extra clicking is the first sign they are beginning to fail. If they fail, the motor will not run, and you'll look at a much higher repair cost. If the startup sounds changed, it's a good idea to call a heating and cooling professional.

AC Hissing Noise

Air Conditioning sounds like hissing

You have probably heard of refrigerants before. But you probably heard it about your automobile.

Refrigerant is the compound that keeps your air blowing cold. Refrigerant is used in vapor compression. It carries heat from a substance or fluid, cools it down, and throws it back into the atmosphere. This applies to a vehicle's air conditioning system and your residential HVAC.

The refrigerant circulates through the AC system in coiled tubing. Hissing points to cracks or leaks in this coiling. If the hole is substantial enough, you may hear a gurgling along with the hiss. This is the most common problem associated with hissing sounds. However, hissing can point to several issues, none suitable for your system.

Some of these other problems could be:

  • Rusted heat pump accumulator
  • Faulty flare connections
  • Punctures in the capillary tube
  • Leaking valves
  • Leaking pump coil

In any case, don't ignore it; call in a certified HVAC repair professional right away to diagnose the system.

AC Screeching Sound

Air conditioning sounds like dinasor

A screeching sound doesn't mean there's a velociraptor nearby. In terms of AC repair, screeching means a problem with the fan motor or compression mechanism in your unit.

Does the screech continue for the entire time the system is running? This points to a problem with the fan motor itself. Does the screeching stop once the system is fully powered up? Your compressor is likely the issue and needs replacing. In either case, it's not a good look. If either of these components goes, your entire system crashes with them.

If you catch the problem early, these are easy fixes. Ignoring the problem could lead to failure that would harm the whole system, which is a more prolonged and expensive fix.

While the screeching is annoying, replacing your entire HVAC system is even more annoying and a bank breaker.

AC Buzzing Noise

In air conditioning repair, a buzzing sound is never a good sign. Buzzing usually equals danger, so turn off your AC immediately. The lesser offenders could be a frozen system. Turn the system off and let it have a chance to thaw out. Try to keep the temperature at a mid-range to avoid future freeze-overs.

A stuck condenser fan could also be the source of the buzz. The condenser fan pulls air from outside and brings it into the home. If a small piece of debris gets stuck the fan can't move. The electrical impulse of the fan to move while stuck is the root cause of that annoying buzz.

Buzzing is also a significant clue of a potential electrical malfunction in the AC unit. Loose wires, frayed junctions, all these can cause buzzing. Why is this so serious?

These types of malfunctions can cause major electrical fires within the walls. Electrical fires account for over 50,000 of the total fires in the US every year. They've caused billions of dollars in damage, hundreds of deaths, and thousands of injuries.

If you hear buzzing, turn the AC system off immediately and call an emergency AC repair service. Your family's life and your home may be on the line.

AC Banging Noise

Banging, like buzzing, is a major concern. It's another reason to jump right away and power the system down. Banging is a surefire clue that something has come loose inside the unit. It might be a bolt or screw. Maybe the fan. In every case, the AC needs that part to function.

Banging can only mean bad news. The loose component could hit a crucial part of the internal equipment. It could cause the fan to stall. The motor could suffer damage. A loose screw could cost you thousands of dollars and some hot, sleepless nights.

So, if your AC is banging, and not in a good way, you should Google "air conditioner repair near me" ASAP.

AC Rattling Noise

Another sign of wear and/or something loose in your unit is a rattling sound. Rattling points to many scenarios. It could be parts that are starting to come loose. It is a good sign your system is deteriorating. Or it may simply be some twigs caught up in the unit and are hitting the fan.

Whatever the cause, you shouldn't ignore a rattling sound. Go out and inspect the unit. Clear it off and make sure no debris is on top. Do a visual inspection of any open gaps in the unit. Do so if you see any debris you can grab and pull out. Check to see if the rattling ceases.

If it's still keeping up, it's best to call in an HVAC expert to give the system a good once-over. After all, it’s better to be safe than sorry.

AC Squealing Noise

Squealing at a high pitch indicates that your air conditioner is under great pressure. High internal pressure can damage your unit, and although it isn't likely to cause permanent damage, it still needs your attention.

The squealing is usually a warning signal from the machine. It will stop the processes because continuing to do so would be harmful to the unit. The problem should be resolved by replacing the compressor. Cleaning it will merely bring back the squealing at a later point.

A squealing noise could also indicate that your belt is having issues. It may encounter a lot of friction and be unable to move as quickly as it would like. This can be resolved by replacing it and wiping off the surrounding element.

How to Fix a Noisy Air Conditioner?

Inspecting air conditioning sounds

Inspect For Any Signs of Loose Blade Placement

Remove the casing from the air conditioner and turn it off. Check to see whether any of the fan blades are positioned incorrectly. If you discover they are, don't attempt to fix it yourself. Hiring an air conditioning professional is recommended to take care of the situation.

Examine The Fan For Any Damage or Debris

Loosen the bolts and screws in the unit to allow you to make any simple fixes on a noisy air conditioner. Remove any debris you can find, such as dust, branches, stones, and other materials stuck inside the unit.

Get Help From an AC Servicing Professional

In most circumstances, it's best and safest to leave the repairs to a skilled aircon professional or an expert aircon servicing company. AC professionals can identify and fix your AC problems right away, saving you a lot of time and energy.

How To Reduce AC Noise Inside?

If an AC servicing professional finds nothing wrong with your air conditioner. However, if you still find it noisy or if you're merely looking for techniques to conceal the sound of a newly installed unit, you can try the following techniques.

Use A Sound Blanket

The compressor produces the majority of the noise in most commercial air conditioners. You may take the top off your AC outdoor unit and place a sound blanket on the compressor. The sound blanket rests on top of it. Much of the unit's sound will be muffled due to this.

Install Sound-Absorbing Fencing Around Your AC

This can also conceal the outdoor component, which many homeowners find appealing. You should choose a fencing material with overlapping boards for sound dampening. You should also ensure that the fence is at least three feet away from the air conditioner to allow it to obtain the airflow required.

Place Some Plants Around Your AC

You can place some plants around the AC, but you'll have to keep them pruned back regularly. To prevent sounds inside your home, you can also place some giant houseplants in front of the windows on the side of the house facing the AC.

FAQ: Air Conditioning Sounds

What does it mean when your air conditioner makes noises?

An air conditioner makes a low, steady blowing noise as it continuously pumps cold air through your home's ducts and vents. This normal noise should be quiet enough to blend into the background. So pay attention if you hear strange or deafening noises from your air conditioner.

Ignoring weird noises from your air conditioner can transform little problems into high prices. These noises could indicate the need for anything from a simple tune-up to pricey repairs or, in the worst-case scenario, a complete unit replacement. The sooner you can figure out what's causing the noise and fix your AC problems, the better.

Why is my air conditioner making weird noises?

An air conditioner that makes weird and loud noises indicates a problem that needs to be fixed. Different problems might sometimes generate the same type of noise. Therefore, it's essential to understand what the various noises may indicate.

Although bothersome, air conditioner noises are helpful because they can alert you to a problem before it becomes impossible or costly to solve, such as fixing a fan motor or compressor.

What does a bad AC compressor sound like?

A bad or damaged AC compressor usually produces loud or unusual noises. Like other accessories driven by the engine's belts, the AC compressor contains multiple inner components and rotates on a sealed bearing. If any of those inner components fail, or the compressor's internal bearings fail, the compressor can make various noises.

A worn bearing makes a high-pitched squealing or grinding noise, whereas a seized bearing makes a grinding noise or a notable belt squeak. Due to the complexity and nature of how compressors are manufactured, replacing the entire compressor rather than trying a repair is usually the best option.

When to Replace a Noisy Air Conditioner?

Replacing your unit may be the best option if your unit is getting old. Excessive noise from an older unit is typically an indicator of its age and could suggest major issues like refrigerant leakage or a malfunctioning compressor. A compressor replacement is also expensive enough that it is more cost-effective to replace the entire air conditioner.

A new air conditioner will be significantly quieter and more energy efficient. You might be able to save enough money on your utility bills that your air conditioner would pay for itself in a few years. However, before purchasing a new air conditioner, do your homework. Many options are available in the market today so take time to research the best AC brands most suitable for your needs.

Connect With The Best Heating and Cooling Company in St. Louis

Ignoring the strange AC sounds isn’t a good idea. We hope this list concerning air conditioning sounds leaves you more in the know. This time when something goes bump in the night, you'll know what the likely cause is and when to call a professional.

Remember, your HVAC system is a sensitive piece of equipment. It's also an investment if they need replacement. Don't try to perform a DIY AC repair. Similar to electrical work, just because you maybe can fix it doesn't mean you should. Call a professional repair team if you hear your system start making any of these noises.

Do you live in Missouri? Are you having some AC troubles? Crystal Heating and Cooling have been in business since 1965. We are the best heating and cooling company in town!

Call us today and schedule an inspection. Want to learn more? Our blog is a great place to start.

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