November 20, 2023
Why is my HVAC system making noise

Winter is right around the corner, and you want to make sure that your HVAC system is ready to keep you warm and cozy. However, when you turn on your unit, you might hear a few noises. Some sounds are part of regular operation, while others could be a sign that you need to schedule a repair service as soon as possible. Here are some noises that you may hear from your heating system and what they could mean.

Normal Noises From Your Furnace

Hearing sounds from your furnace is not necessarily unusual. These noises can vary in frequency, nature, and intensity. Trying to differentiate between these normal sounds and potential issues takes a lot of work. Before you call a repair service for your system, here are some of the typical operational sounds.


If you hear a low humming, there is no need to panic. This common sound can often be heard as background noise coming from your HVAC system. As the blower fan operates, it produces a low hum. That sound is the warm air circulating throughout your home.


When the furnace ignites, a clicking sound can be heard. During this process, the gas valve opens. With that, the gas can flow from the igniter to kickstart the flame.


Your furnace runs in cycles. As the unit warms up or cools down, some of the components may expand or contract. You might hear a few popping or clicking sounds at this time.

Air Whooshing

To get heat to your rooms, conditioned air must pass through the ductwork in your home. This air movement can cause gentle whooshing in your home. You shouldn’t be worried about these noises since they are the sounds of air circulation.

Sounds Worth Paying Attention To

Now that you know the common sounds of your furnace, here are a few that you will want to take a closer look at.

High-Pitched Noises

If you are hearing any whistling or high-pitched sounds, this could mean you have problems with the air pressure or flow of your HVAC system. While these noises can be annoying, they are often easily resolved.

For example, a dirty air filter may be to blame. A clogged or dirty filter will restrict airflow, often leaving you with high-pitched sounds. You need to change the filter about every one to three months, depending on the type of filter you’re using. If you hire someone for maintenance, then they will be able to show you how to complete this task. Keep in mind that not all filters are the same. You will want to get the right type for your furnace and needs.

If an air filter change does not help, take a look at your vents. With a quick walk throughout your home, you can see whether you have closed or blocked vents. Any obstructions can block the natural airflow of your system. As a result, you might hear whistling sounds. Sometimes, debris may have fallen into the vents. Once you address these issues, you should have a noise-free ventilation system.

Some problems can be a little more complicated. Damaged or leaky ductwork leads to air entering or escaping your system. In turn, that creates whistling noises. These issues will require a professional for a thorough inspection and repair.


When you are trying to sleep, the last thing you want to hear is a rattling noise. These sounds can be caused by worn-out or loose parts. Bolts and screws might become loose over time. When the unit clicks on, it can cause some vibrations. Tightening down those fasteners can help prevent these sounds in the future. Many times, you can prevent these noises with a bi-yearly maintenance visit.

Also, a check of the blower wheel may be beneficial as an unbalanced blower wheel is another cause for rattling. If the motor is not unbalanced, it may just be worn out. Sometimes, a replacement is the only solution to this problem. A professional technician should handle any repairs needed.


If you hear banging sounds while your HVAC system is running, there could be serious problems to worry about. Many times, this problem may be attributed to a malfunctioning ignition system. When the system does not operate correctly, it can lead to erratic or delayed lighting of the burners. During this time, you might hear a pop or bang. Don’t ignore these problems. You need someone to look into the issues to make sure the system is safe to operate.

As the warm air pushes through the ducts, it can cool down or heat up the metal. In turn, it causes it to contract and expand, leading to loud banging sounds. If this is happening in your home, a little insulation can help reduce those noise levels. Along with that, you can save money on your bills by improving the system’s energy efficiency.


Some clicks are part of the normal operation of an HVAC system. If you continue to hear these sounds, you may want to get them checked. These sounds are often tied to contraction and expansion. When the materials in a furnace heat up and cool down, this can create a few clicking noises. Many times, these sounds should not cause alarm.

Unfortunately, these clicks could be an indicator of larger problems though. For example, you should have the control panel or relays inspected. These components might be malfunctioning. As a result, your furnace will be working at a reduced level. If you ignore these problems, it could even lead to a non-functional furnace in the future.

Screeching and Squealing

Screeching and squealing sounds are often the result of a bad blower motor or fan assembly. Many times, the bearings can wear out, causing you to hear these noises. Replacing or lubricating the bearings will stop these squeals.

If your furnace uses a belt-drive assembly, then a loose or damaged belt could be the culprit of these high-pitched noises. Often, the belts will need to be replaced. However, leave this job to a qualified technician.

Motors are the cause of many unusual sounds. A broken blower motor will lead to screeching sounds. Many times, the motor will need a total replacement to stop those screeching noises. After the replacement, your system should run without any annoying sounds.


While not a common sound, these noises come from water in the system. Some high-efficiency furnaces produce a lot of condensation. If the line is blocked, then you might hear a few gurgling sounds. A technician can inspect the line and clear out any debris.


If there’s one sound you don’t want to hear, it’s a loud explosion. These booms are often very dangerous. Typically, that is tied to a delayed ignition. When the gas builds up, it can result in a loud boom as the ignition clicks. Many times, a dirty burner or gas valve can also cause a booming noise.

If you are hearing unusual sounds coming from your HVAC system, it’s time to call an experienced team in Las Vegas. At Polar Air & Heating, Inc., we offer a wide range of services to ensure your comfort and safety. Our team of skilled technicians is ready to deliver prompt and reliable solutions for your heating and cooling systems. Along with that, we can assist with ductless mini-split services, indoor air quality assessments, new construction projects, humidification, and more. Contact Polar Air & Heating, Inc. to schedule your next home visit.

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