Furnace Making Noise

A furnace that is making loud, unusual noises is definitely a cause for concern. Furnaces can make noise for a number of reasons. As a homeowner, it is vital that you understand the cause so that you are knowledgeable on how to handle the situation. Keep in mind that although you can fix some of the issues yourself, it is best to let a professional HVAC contractor repair the problem.
There are many reasons your furnace can make different noises. We have listed some of them in this article below:


Gaps in the ductwork can create a whistling sound. Listen carefully as to where exactly the sound is coming from. It is usually caused by a small tear near the connecting point between the duct and the furnace, near the blower. It can also be because the ducts are too small. Consequently, you will need larger ducts for greater airflow.
Another reason for the whistling sound is a clogged filter. Because of the dense buildup, the airflow is blocked so the fan tries to suck air from anywhere it can. The whistling can come from even the smallest of holes while air is getting sucked through them. To see if this is the cause, remove the filter and see if the whistling stops. This is best remedied by replacing the dirty filter with a new one.


When you hear the sound of metal scraping metal, the problem might be with your blower wheel. If this is the case, your furnace won’t be able to heat your home adequately. Have a trusted technician fix this issue immediately.


A high-pitched squealing noise generally indicates that a furnace component needs to be replaced or repaired. Worn out parts like a faulty blower motor or a frayed blower belt can create this sound. It would be best if you got this fixed right away before they cause any major damage to your heating system.


A rattling sound can be one of two things. First, it can be caused by a loose panel or a loose screw. Before you attempt to find this loose panel or screw, you first need to make sure you switch the power off directly at the source. Use the right screwdriver to tighten the panel and check to see if it fixed the rattling noise. If you don’t feel comfortable performing this task, then call a local HVAC contractor.
If that didn’t fix it, then the rattling sound is a sign that there is a crack or leak in your heat exchanger. This is a severe issue as a damaged heat exchanger can leak carbon monoxide into your home. This situation can be dangerous and potentially fatal. Call your local HVAC technician immediately if the rattling isn’t solved by tightening a loose screw or two.


When you turn your furnace on and you hear a banging sound, there are two likely causes. If the banging is coming from somewhere in the duct, also known as oil-canning ductwork. This means that there is a weak spot in the ducts. You need to screw a thicker piece of metal across and onto the weak spot to add support. To really fix the issue, call a local HVAC contractor. A heating technician will understand how to best solve the issue.
The other possible reason for the rattling noise is an ignition roll-out. This issue can be a cause for concern. It is a little explosion, or a bigger-than-normal flame that occurs during the furnace startup. To determine if this is the case, listen carefully as to where the noise is coming from and watch the furnace doors if they are shaking. If they are, open the burner compartment door to see if the banging still happens and to see what happens inside. Once you are sure that it is an ignition roll-out, call an HVAC specialist. A professional has the knowledge and training to remedy the problem.


A rumbling sound in your furnace usually indicates that your heating system hasn’t been maintained for quite some time. The pilot light needs adjusting or the gas burners are dirty. If you hear a rumbling noise coming from your furnace, check to see if the furnace flame is blue. It is fine if it has a tiny yellow tip. However, if the furnace flame has a lot of orange, yellow, green, or purple, then it means that you have an inefficient and possibly hazardous condition on your hands. Contact your local HVAC technician to diagnose and repair this problem immediately.

Motor Noise

If you think that the sound is from the furnace motor, this can be because of something called bouncing. To improve this, you can place a sturdy piece of styrofoam below the squirrel cage. However, it is better to contact an HVAC company to solve the problem.


These are just a couple of the potential furnace noise problems you may face. You can avoid most of these furnace noises from happening by scheduling routine furnace maintenance with a qualified HVAC professional. Make sure to contact a reliable and trusted heating specialist to conduct a safety and diagnostic check on your furnace. They can repair all the current issues and ensure that your furnace operates as expected.