Why Is My Furnace So Loud?

Posted on: 20 October 2020


Ideally, your furnace should not make any noise at all. A simple clicking sound when it turns on and off should be all you hear to signify that your furnace is working and operating correctly. If you hear other sounds while it's operational, then it's time to call an HVAC company to schedule heating services.

While every sound that your furnace makes can be concerning, some are more worrisome than others. Below are a few of the ones that you might hear coming through your vents; if you hear any of them, make sure you get it looked at immediately. Failure to do so could result in small issues becoming major problems down the road, resulting in higher heating service bills or a complete furnace replacement.


As mentioned above, usually you hear two clicking sounds: one when your unit turns on, and another when it flips off. A constant clicking during the cycle itself indicates that your unit is switching on and off and won't stay lit for whatever reason. A clogged gas valve will limit the amount of energy that gets to the ignition source, and will not let the unit turn on properly. Alternatively, if you hear the clicking sound coming from the ductwork, it could be air passing by a connection point that is loose.


If a washer or bolt breaks off and is inside your ductwork, it can produce a loud rattling sound that can sound. Another possible reason for that rattling sound could be a broken fan blade that is chipped off and is banging away inside your unit. Both need to be fixed by a licensed furnace repair technician, but once the initial problem is taken care of, you shouldn't have any more problems. Another possible reason for the banging sound is a loose unit that isn't anchored properly to your flooring.


Furnace maintenance includes checking the ductwork on a regular basis to make sure the connection points are still intact. If they're not, the air passing by and through those loose connection points will create a loud whistling sound in your air vents. It's annoying, to be sure, but it also is indicative of a lot of lost energy escaping through your vents that will translate to higher energy costs as well. Schedule a heating repair service to have it looked at since this is not something you want to try and attempt on your own.

For more information about heating service and repairs, contact a local HVAC contractor.