Why Is My Furnace Making Noises?

gas furnaceIf you live in an area of the country with hot summers and cold winters, you are undoubtedly used to making the switch from air conditioning to heat when the cooler weather inevitably hits. However, after a long, hot summer of no use, you may notice that your furnace isn’t running as well as it once did. Or, in the middle of a freezing winter, it may suddenly start acting up. In this guide, you’ll learn more about some of the noises furnaces can make and what they usually mean!

Whistling noises

When a furnace is making whistling noises, one of the most common causes is that there are gaps in the ducts. If possible, try to pinpoint the source of the whistling sound. The odds are good that you will find a small hole or space near the point where the duct and furnace blower meet. Whistling can also be caused by a clogged filter; replacing the filter should fix this issue.

Rattling and vibration

If your furnace or ducts have started making rattling, vibrating sounds, there are a few steps that can be taken to fix the problem. First, check to make sure the screws attaching all the ducts are securing; the repair may be as simple as tightening any loose ones. If that isn’t the issue, use duct tape to attach any loose ducts or other objects that are hanging off of the furnace. Finally, if you are still experiencing rattling and vibration, add a cork pad under the furnace itself.

Motor noise

If the noise your furnace is making seems to be coming from the motor, it may be the result of the motor jiggling or bouncing around. This can sometimes be fixed by having a professional put a piece of styrofoam alongside the motor. If that doesn’t fix the noise, the motor’s bearings probably need to be replaced, which is another task for an HVAC expert.

Banging noises

In the event that your furnace is making banging sounds when it turns on, you are probably dealing with one of two problems. The first is oil-canning ductwork. This simply means that part of a duct has “oil-canned” and needs additional support in order to function properly. A professional may recommend replacing the duct or may simply add a sturdier piece of metal to steady it.

The second potential issue is ignition roll-out. This is a fairly rare problem but can be serious. Its trademark is a too-large flame when the furnace kicks on. If you think this is what is going on in your house, contact a reputable HVAC company right away.


No matter what is going on with your furnace, the best thing to do is contact a professional who can take a look and provide you with service options. Dealing with furnace problems by yourself could actually make things worse, so give our team a call today at (781) 639-9222.

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