Air Conditioner Making Noises: Pulsating, Humming, and Buzzing (FIX Them)

Air conditioners make different types of noises. Some of them require attention, while a few of them are normal. Manufacturers usually mention noises during starting, operating, and stopping after a cycle of functioning. You need not be alarmed by these sounds.

There are other noises, such as humming, pulsating, and buzzing. If your machine experiences these types of sounds frequently, it’s time to take the call.

This article will explain everything about AC noises and their remedial measures. Take this as a quick guide whenever your unit makes strange sounds or browsing for a new HVAC unit for Summers. Knowing your machine helps with optimum performance and stunts the ‘do-it-yourself’ trend.

We will list noises, common reasons, and ways to solve them for a comprehensive and knowledgeable solution.

Let’s get started….

Why Is Air Conditioner Making Banging or Rattling Noise?

The air conditioner making the rattling and banging noises is a situation of worry. There are two probable reasons: Damaged part in the compressor and Dysfunctional fan.

Damaged compressor generally is costly to replace, especially with older units (more than ten years). You can spend a few extra dollars and get a new AC.

Check your warranty if your unit is from brands such as Goodman, Amana, and Daikin. They usually offer a lifetime exchange warranty for the broken compressor. If eligible for a warranty, you will require to pay only labor costs of around $300 to $500. 

If your fan is damaged, the repair will cost $250 to $700.

Fix AC Banging or Rattling Noise

Check the machine for any accumulation of dirt and debris. It could be hitting the fan and making a rattling sound. If found any debris, clean it and see if the problem is solved.

Call the expert if there is no debris and the compressor or fan is making strange noises. Before calling, take a couple of quotations online and in your locality. Compare services, consider the age of the unit, cost to repair, and finalize the technician.

Another scenario is banging or rattling sounds from the furnace or air handler inside the home. The most common cause for this could be a damaged fan motor. It needs a technician to repair or adjust the imbalanced fan motor. It is advisable not to try by yourself because it could further damage the machine.

Why Is Air Conditioner Making Buzzing Noise?

The air conditioner makes a buzzing noise because of multiple reasons, such as;

Dysfunctional Contactor

If there is a lousy contractor, electricity will not go through and unable to reach the compressor. It generates a loud buzzing sound. You need an authorized technician to repair the contactor. Their average charge for a repair contractor is around $180. You can also try DIY here through proper understanding and reading the user manual.

Dysfunctional Capacitor

If there is a problem with a capacitor, the air conditioner fan will not function and create a buzzing sound. To solve this, try a wooden stick or plastic stick to move the fan blades. If it does work, call for repair or replacement.

Problem with the Compressor

The compressor is the heart of the air conditioner and replacing it cost you a lot. If the problem is with the compressor, consider spending a few extra dollars and buying a new unit. Usually, when the compressor is wrong, it would not function despite having power circulation in the HVAC product.

Loose AC Parts

There are parts in the unit that restrict vibration during the functioning of the machine. If they are loose or installed improperly, the air conditioner will make a buzzing noise. Check it yourself and call an HVAC expert to tighten the parts.

Frozen Indoor Air Conditioner

Multiple reasons can cause frozen indoor AC. It is advisable to consult a professional to diagnose and solve the problem.

Why Is Air Conditioner Making Pulsating Noise or Harmonics?

The air conditioner on the plastic pad and refrigerant lines contacting the nearby wall can generate pulsating sound. To solve this, change the plastic pad with a wood pad or something that does not move with sound waves from the compressor’s movement.

If there is a wall issue, insert rubber or foam and keep the refrigerant lines at a distance from the wall.

Pulsating noise can also generate from a loose fan or its blades. Check the fan and if the problem is in its fitting, call an AC technician to repair this.

Why Is Air Conditioner Making Hissing Noise?

The most common cause of hissing noise is leaky refrigerant. It could be due to several reasons such as;

  • Broken refrigerant lines
  • Damage from weed trimmer or lawnmower
  • Loose connection because of deterioration and use

A leaky refrigerant needs immediate repair. If left untreated, there could be no air conditioning and an uncomfortable indoor atmosphere. The repair cost is around $200, and if it requires changing the refrigerant, the price will be about $400 – $1,500.

Why Is Air Conditioner Making Squealing or Squeaking Noise?

A dysfunctional motor bearing generates a squeaking sound. Check the sound. If it is coming from an outside unit, the problem is with bearing in the fan motor. If the sound is coming from an indoor unit, check the bearing in the blower motor.

You can try DIY by reading the user manual and watching training videos to understand the technicalities. Otherwise, it is always good to call for expert help for HVAC products.

Why Is Air Conditioner Making Whistling Noise?

Air conditioners make a whistling noise when air circulates cracks and crevices of the furnace cover or air handler. It usually happens due to accumulated dirt and debris in the air filter. Keep your machine clean to avoid such noises.

The unit also whistles if the air duct is leaking and not sealed properly. Call for a technician to diagnose, wrap, and insulate all ductwork.

We should be worried about these noises and need professional or DIY attention. 

We are also listing here normal sound that does not harm your machine to get you all informed.

Normal Sound Made By AC

  • Refrigerant or Coolant circulates indoor and outdoor through the compressor. It makes a gurgling sound while entering the coil.
  • The compressor shuts off when a cooling procedure finishes. It creates a difference in pressure between refrigerant lines and compressors. It can generate a loud noise such as clunk, shudder or click. It’s a normal part of the AC operation.
  • Soft humming sound from the motor running inside the unit.

Concluding Remarks

We have covered most of the noises that come from air conditioners. Read this guide for a quick reference. The machine’s longevity depends upon the timely diagnosis of the problem and correct remedial measures. 

If feels any confusion about sounds coming from the machine, call an HVAC expert, and they will explain the problem and the solution. 

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