Hear the Warning Signs: 7 HVAC Noises You Shouldn’t Neglect


Is your HVAC system creating odd sounds? Those odd sounds you hear could be a wake-up call for an impending repair. Almost every household appliance makes noises and we get used to them. But if they are producing sounds that are not normal, we should not ignore them as they can be a signal of more serious issues. 

It’s important for owners and renters to learn more about this problem. Here are the most common HVAC noises, what they mean, and what to do if they occur.

1. Clicking

Depending on where the clicking noise is originating from, it might suggest a few different problems. If the clicking is coming from your HVAC equipment, there might be a problem with the compressor. This is an issue that should be addressed by an expert. If the clicking is coming from your furnace and you have recently turned on the heat, it is usually an indication that your system is working well. However, if the clicking continues, contact a specialist because the problem might be in the ignition system, which is terrible news.

2. Clanking

Similar to the thwap and thunk sound, these HVAC noises might be produced by anything being dislodged or caught in the fan or blower. If the rattles and clanks become bangs or have continuously grown in loudness, it’s advisable to bring in an expert to evaluate which sections require HVAC maintenance or repair.

3. Popping

A popping sound after turning on your heat or air conditioner for the first time in a long time may not be a reason for alarm. This is frequently caused by the ductwork expanding or otherwise adapting to the change in air temperature, and it should subside within a short period of time. If the popping sound persists, or if you have not recently encountered any significant fluctuations in temperature, it may be a good idea to seek the assistance of an HVAC repair professional.

4. Thwapping

If your HVAC noises are more thwapping or thunking, it might be as simple as an object trapped in the fan blades. Keep an ear out for a difference in loudness when your air conditioner is turned on and off. If you only hear the noise when the air is blowing, your fan blade may be broken. You may be able to locate the obstruction and remove it yourself, but if you are unclear whether you require HVAC repair, contact an expert.

5. Buzzing

When your air conditioner or condenser buzzes or hums, it might be that the compressor is broken or the power is too hot. Another reason for a buzzing AC is worn-out condenser rubber feet. This causes the condenser to tremble and hum. Buzzing might be a sign of a loose component or a leak. In any event, if you hear a buzz, call your HVAC professional.

6. Squealing 

AC systems will scream like a car with a loose belt. A loud screaming suggests a worn or misplaced fan belt. Also, bear in mind that humidity can cause a fan belt to expand or compress, throwing it out of alignment. Another reason for this screaming might be a shortage of lubrication in the engine. In this situation, a particular type of lubricant may be used to remedy the problem. If you hear screeching, keep your AC running but call an HVAC professional immediately away. 

7. Banging

A hammering sound indicates a loose or broken item. A loose or broken connecting rod, piston pin, or crankshaft commonly causes this AC noise. Listen for pounding and contact your HVAC specialist. They can help diagnose the issue, find the source of the pounding, and determine what can be done.


These are the most common HVAC noises that you as a homeowner may hear. Your system may make other noises as well. If you’re worried about the sounds your HVAC system is making, don’t hesitate to contact HVAC repair and HVAC maintenance specialists. 

They’ll take care of the problem quickly. It’s better to be cautious than sorry, and it’s good to pinpoint the source of the problem as early as possible.Mainline Heating and Air 

Mainline Heating and Air has been providing dependable heating and air conditioning service in the Alabaster, Birmingham, Jefferson/Shelby, and Pelham county area since 1989. We also offer quality products, including air conditioners, air handlers, gas furnaces, heat pumps, home generators, package units, tankless hot water heaters, humidifiers, UV lights, dehumidifiers, and filtering systems. Our excellent team of experts aims to help you select the comfort system that best suits your home and your resources. Contact us today at (205) 664-4751. 

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