Why Is My Furnace Making Noises?

Feb 26, 2021 | Furnace | 0 comments

When we at Kettering-Oakwood Heating & Air get a call from a homeowner in Ohio, one of the most common questions is “why is my furnace making noises?” Modern furnaces are designed to be as quiet and efficient as possible, so when unusually loud or disruptive sounds begin to emit from your heating system, you know there is a problem. There are many different noises that your furnace may be making, and each of them points to possible problems. While it’s important to allow a licensed professional to take care of fixing your furnace, it’s helpful to know when the noises occur and what sort of noises your furnace is emitting.

Types of Furnace Noises and What They Mean 

While it’s common for furnaces to make quiet noises every now and then, loud and recurring noises can signal a problem with your furnace. There are five types of common noises and each of them point to different problems within your furnace. The first step you can take is to observe your furnace often (when it turns on, turns off, or is running) and to make a mental note of when the noises are happening, and what they sound like.


The most worrisome noise you can hear coming from your furnace is rattling. Unfortunately, a rattling noise can mean two very different things: your furnace could just have a loose part, or your heat exchanger could be cracked. Because heat exchangers are one of the most important and most expensive parts of your furnace, repair can often be just as expensive as buying an entirely new furnace. That is why it’s important for you to contact a licensed repair company so they can identify the problem as quickly as possible.


Another noise you can notice your furnace making is a high-pitched squealing noise. This noise typically signals a problem either with your furnace’s blower, or it can signal that there is low air flow in your heating system. Either of these problems can sometimes be fixed by replacing your air filter, so try giving your furnace a new air filter. You know you’ve fixed the problem if the squealing noise goes away, and it may be a good idea to consider changing your furnace filter more often. If the noise does not go away, then you should call a repair company so they can inspect your furnace and give you other options for repair.


Banging is perhaps the most common noise that homeowners hear coming from their furnace. Additionally, it can be the hardest to determine whether there is actually a problem with your furnace, or whether the banging is normal. This is because furnaces tend to make quiet bangning noises when they turn on or off. However, if the noises persist or grow increasingly louder, then you can assume there is a problem with your furnace. If the banging is unusually loud right when you turn it on, then there may be an issue with your furnace’s gas ignition system. If the banging occurs after your furnace has turned on and is running, then it may be because your air ducts are expanding or contracting. A minimal amount of expansion or contraction is normal, however, a problem can occur if your air ducts are bent, or if your vents are closed, or if you have a dirty air filter. So check your heating system for these three things. You can easily change your air filter or open your vents, but call a technician if your air ducts are bent. 


Have you ever used a gas lighter or stove before? If you have, then you are familiar with the clicking noise which results in flame. The same process is used with furnaces, and a repetitive clicking noise coming from your furnace signals that the ignition system is malfunctioning. This is commonly caused by dirty burners, low levels of gas supply, or a malfunctioning flame sensor. If the clicking sounds more like clanging (or sounds like metal on metal) then it may mean that there is a loose bearing in the furnace’s fan motor.


While it’s normal for your furnace to have a slight hum when it’s running, a louder humming or buzzing sound usually means your furnace is having electrical issues. This can equate to things like a bad inducer motor, a broken transformer, or a faulty blower motor capacitor.

Have Questions?

If you have any questions, or have noticed an unusual sound that isn’t listed here, then you can call Kettering-Oakwood Heating & Air today at 937-502-3842. We are always happy to answer your questions or we can schedule an appointment for you over the phone. Or you can schedule an appointment online now by clicking here! When it comes to your furnace, unusual noises should never be ignored, so it’s important to address any concerns you may have right away!