November 8, 2023
Why is my furnace making so much noise?

When you hear strange or unexpected noises from your furnace, it may cause concern. In some cases, these sounds are just a part of the unit’s normal operation. However, other times, these noises may be a sign that you need to call a repair service to inspect your furnace. Here are a few things you need to know about those furnace noises in your home.

What Are Normal Furnace Sounds?

Your furnace will make sounds when it is operating. You cannot avoid that in your home. All units will make some type of noise. The key is knowing the difference between normal and unusual sounds. Here are some sounds that are expected to be heard in your home.

Motor Hums

The furnace contains several types of motors, such as a blower motor, fan motor, and compressor. You might hear a soft hum in your home when these components run. These motors are working to maintain the desired temperature in your house.

Air Moving Through Ductwork

All furnace systems have a series of ducts to move heated air from one space to another. As that air flows through the ductwork, it will create a sound. These sounds might be more noticeable when you have several floors or an expansive system of ducts. However, these sounds should only be heard at a whisper level.

Thermostat Clicks

At the heart of your furnace is the thermostat. This device helps to regulate the temperature in your home. When it turns on, you may hear a few soft clicks. With that sound, you know that the thermostat is beginning the heating cycle or entering standby mode.

Now that you know about the regular sounds of a furnace, what are some of the ones you should worry about?

Sounds That May Cause Some Concerns

While the above sounds are perfectly normal, a few require you to call someone out to investigate. These unsettling noises often hold clues about potential problems in your furnace. They include:

Banging or Rattling

Normal furnace sounds should never be disruptive. If you have any banging or rattling sounds, it could mean the damaged or loose components in your system. Poor-fitting panels, loose screws, or damaged blades could all be the reason behind these sounds.

If you are experiencing those noises, make sure to schedule an inspection of your furnace. A technician will be able to tell you if there are loose, damaged, or broken parts. With that, you can get those items replaced and put an end to the loud noises.


If you are starting to hear hissing, that might mean there are air leaks in the ducts. When that happens, it can disrupt the smooth flow of air. These sounds are not only unsettling, but they can greatly affect your energy and utility bills. Along with that, it will put a damper on the comfort levels in your home.

Once again, you will want to contact a professional HVAC team for an inspection. They will thoroughly analyze your ductwork, looking for any signs of leaks or damage. In many cases, your duct may need a reseal or more insulation to eliminate those leaks. Sometimes, the issues can be remedied by replacing the air filter in your furnace unit.

Screeching and Squealing

You never want to ignore these sounds. They are telling you that something is wrong with your furnace. Many times, these sounds are the result of a worn-out or unlubricated blower wheel or fan motor. When there is friction, it can cause these distressing noises.

An HVAC technician will need to take a look at your system. They may have to replace these parts or just add a little more lubrication to reduce the friction. If you want to avoid these problems in the future, make sure to schedule a regular maintenance visit. During these service calls, the technician will inspect your furnace and ensure everything is cleaned, lubricated, and ready for the next heating season.


Another unnerving sound is a clicking or thumping noise. Often, this occurs because there is an imbalance with the motor or blower wheel. In turn, that results in them hitting the side of the housing.

Getting these components in balance is not a DIY project. For that reason, you will want to consult with a professional technician. They have the right equipment to balance the motor and blower wheel, helping them get back into the right spot.

Popping or Clicking

Sometimes, your furnace system will naturally expand and contract, leading to popping sounds. These sounds might be really noticeable when the system starts or shuts down. In many cases, this is a part of the daily routine of your unit. However, if the clicking or popping is persistent or disruptive, you may need to schedule a service call. There could be underlying issues that are causing those annoying noises.

How to Prevent These Noises

There are a few steps that you can take to create a more comfortable and peaceful environment in your home. Let’s take a look at a few of them.

Schedule Regular Maintenance

You cannot avoid regular maintenance and hope that your system will operate to its full potential. By setting up a service call, you can avoid many of these noise-related problems. During the check-up, a technician will conduct a series of tasks that are meant to keep your furnace in top shape. They will replace worn-out elements, lubricate moving parts, and tighten down any loose components. Along with that, regular maintenance can extend the life of your furnace, meaning that you can rely on it for years to come.

Filter Replacement

Replacing a filter is a part of regular maintenance. You don’t need to call a technician for these tasks. About every one to three months, you will want to switch out the filter with a new one. This easy step can prevent some noise issues. Along with that, it can minimize any strains on your furnace. In turn, that makes the unit more efficient, and you stay comfortable throughout those chilly months.

Duct Inspection

Many homeowners do not think about their ducts until there is a problem. However, you should have an inspection completed at least once a year. During this time, the technician will look for gaps in your ducts and seal the problem areas. With that, you can have a quieter system and reduce energy waste.


Sometimes, with regular operation, parts can become unaligned or lose their lubrication. When that happens, you need a tune-up for your home. With a few adjustments, a technician can reduce these noises so that you can enjoy a peaceful home environment.

Ask for Professional Help

In any case, you will want to consult with a professional HVAC technician. These professionals have the skills and training to examine and repair any problems with your furnace, especially those annoying sounds. They can help you find the source of the problem and fix it. You should never try to self-diagnose these sounds by yourself. You may end up damaging your furnace with a DIY fix.

Beyer Air Conditioning & Heating has been helping San Antonio residents with their heating and cooling problems since 1990. We provide a wide range of services, including installations, replacements, repairs, and maintenance visits. We even offer maintenance service plans to keep your furnace in top shape throughout the year. If you would like to schedule a visit with Beyer Air Conditioning & Heating, give us a call today!

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