What Do the Noises from Your HVAC Mean and How to Fix Them?

Just Filters

Last Updated on August 14, 2023 by

The latest HVAC units have been designed to produce little or no noise. Therefore, if there is a disruptive and loud noise coming from the unit, it is an indication that there is a problem that must be fixed immediately. The noise from the unit is a sign that there is a need to call for repair services. However, before you do that, understand each type of noise to know what you are dealing with.

Banging Noise

If there is a banging noise coming from the unit, it indicates an issue with the compressor. The work of this part is to distribute the refrigerant to the system to remove heat from the house. As your air conditioner comes closer to the end of its life, it is common to hear a banging noise due to a loose compressor. Call a professional to fasten the compressor and check for any other damage. If not fixed, the noise can worsen, and you may need more expensive repairs.

Hissing Noise

A hissing noise could mean a moderate or severe leak in the air duct. The sound may also result from a defective expansion valve or an incompatible air filter. Therefore, it is advisable to call a licensed professional to inspect the unit. You can also buy compatible air filters from Just Filters and see if the problem goes away.

Buzzing Noise

You may also hear a buzzing sound from the unit. The sound signals unbalanced or loose fan blades. It may also result from faulty fan motors or loose parts of dirty coils on the condenser. The noise could also mean an obstruction close to the copper lines connecting the air conditioner. It is advisable to call for professional repair services to have the compressor repaired and loose parts fastened.

Bubbling Noise

The unit may also make a bubbling noise because of excess moisture. The issue may be because of a crack, hole, or blockage in the drainage pipe. Call licensed technicians with the right tools and skills to fix the issue once and for all.

Humming Noise

A humming noise from the unit can seem harmless. However, it represents an issue with the relay switch. The contractor switch will start the condenser unit outside when you switch on the thermostat. Once this switch malfunctions, you cannot turn on the system unless it is inspected and repaired. So, immediately to hear the humming sound, call a professional service provider to inspect the unit and repair the issue to avoid more damage to the central air conditioning unit.

Screeching/ Squealing Noise

The screeching or squealing noise could mean that the fan motor has malfunctioned. The HVAC unit has a fan motor inside to help remove heat from the refrigerant. Therefore, if you are hearing screeching noises, it means the motor could be broken. You may also notice that the unit is ineffective in removing heating from the house. So, turn off the unit and call for repair services to prevent more issues in the future. Ensure you also apply seasonal maintenance to keep the unit in good working condition.


It is advisable to call a licensed professional whenever you hear any of the above noises from your HVAC. Also, make it a habit of buying compatible components like air filters to ensure your unit is functioning well.

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