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7 Sounds You Don’t Want To Hear From Your Heating System

When winter is coming on, it can be surprising how quickly we adjust the thermostat to give us a little heat in the morning to take the deep chill off the house. Even if your furnace or boiler has been working well throughout the winter, if you start hearing one of these seven sounds, you may have a problem and need to contact a heating professional before it turns into an even larger repair bill.

1. Scraping Sound

A loud scraping noise, a grating metal-on-metal sound, coming from inside your system could be a serious problem with the blower wheel. Maybe the wheel is coming apart from the shaft and scraping the casing or in some other way the motor is causing the wheel to scrape the casing. Turn off the heat pump or furnace immediately and call an HVAC service company.

2. Fast Clicking/Flicking Sound

Remember that sound when you were a kid and attached a playing card to the spokes of your bicycle wheel? If you hear that kind of fast the wrapping sound from your furnace, something might be stuck on one of the blower wheel blades or one the housing around the wheel. While your heating system may be working just fine, this stuck object is causing resistance and it will cause excessive wear on the motor. Get it cleaned up by a professional technician.

3. Squealing Sound

A squealing noise from the blower motor could be caused by a belt wearing out. That’s normally not an expensive repair and best taken care of before the belt stretches further or breaks.

4. Grinding Or Metal Groaning Sound

A bearing problem in the blower motor will make a dull repetitive groan. Some blower motors have ports for adding lubricant, but some are sealed. Adding lubricant will often eliminate the groaning sound, but you have to use the correct oil, not WD-40. An HVAC company doing an annual maintenance inspection on your furnace would like do this kind of lubrication.

5. Rattling Sound

If you hear a rattling sound from your heat pump unit outside of the house when the unit is coming on, the hardware around the compressor could be loose. An HVAC service repair person should be contacted.

6. Popping Sound Or Banging Sound

If you turn on the furnace or boiler for heat and you hear popping sounds or a distinct banging sound (like from a cap gun), the system probably has dirty burner that need to be cleaned. The fuel is not being ignited right away. Instead it’s building up and then igniting in a mini-explosion. You’ll want to get this serviced by a professional immediately.

7. Gurgling Noise

Are you hearing a gurgling noise in your boiler baseboards? You may hear the noise in many rooms or it could be in just one room. This is probably air in your hydronic heating lines. If not taken care of you can damage the circulation pump. This is will need to be serviced by a professional.


When operating properly, your heating system should be fairly quiet, but if you’re hearing one of these seven sounds you really should contact an HVAC professional to come in and repair the problem before it turns into an even bigger problem.