Furnace Sounds You Shouldn’t Ignore

Late last year we covered weird furnace smells, but now that your system has had a whole season of use, are you starting to hear any strange sounds? Don’t be alarmed, it’s normal to hear some sounds coming from your furnace. After all, it’s doing an important job and that important job requires a lot of work. But, what about the sounds that leave you wondering? That’s why we’re sharing furnace sounds you shouldn’t ignore.


To be honest, some chirping is totally normal. If you turn on your system at the beginning of the season and hear chirping, there’s no need to worry. Chances are they will level out at the season wears on. If you’re still hearing chirping sounds in February, there may be a problem. Chirps can indicate problems with a fan belt, or something similar. If you’re still hearing chirping coming from your system—and you’re sure it isn’t a bird—schedule an appointment with one of our friendly HVAC technicians.

Loud Booms

Most, if not all, furnaces make booming sounds. Oftentimes it’s the sound of your ducts expanding and contracting to push air through your home. What you should be on the lookout for are excessively loud booms. If you hear a boom that sounds like it could shake your HVAC system, pay attention to it. Those loud booms could be caused by too much gas being released when the furnace ignites. As we mentioned before, small booms are not a problem and very normal for furnace ignition, large booms can put stress on your furnace and surrounding HVAC equipment. If you’re hearing loud booms on a consistent basis, call your HVAC contractor as soon as possible.

Metallic Scraping

One of the furnace sounds you should never ignore is metallic scraping. If you hear something akin to grinding gears, nails on a chalkboard, or metal scraping against more metal, it likely means you have a problem with the blower wheel of the furnace. This noise could mean a few things in relation to the blower wheel. It could mean the wheel is loose, in which case you would need an HVAC technician to come in, disassemble your system, and refit the wheels. Or, it could mean your wheel is entirely broken. If the blower wheel is broken, your whole system will not work. If you hear a scarping noise coming from your furnace, call an HVAC technician immediately. A loose or broken blower wheel can cause damage to your whole system.


Every once in a while, your furnace will rattle, a short, sporadic rattle is common and shouldn’t be cause for concern. If you’re hearing a constant rattle, that’s a furnace sound you shouldn’t ignore. A constant rattling could mean your motor or fan is worn or broken. If the rattling is getting louder over time, that could be noise of complete system failure.

Squealing or Screaming

You know the squealing noise a car makes when a belt is loose? If you hear that noise coming from your furnace, call an HVAC technician immediately. While squealing, screeching, or screaming may not sound like a big deal, it could become a larger problem later. Very similar to cars making the same noise, one of the causes of a squealing furnace could be a loose belt. Loose belts are fairly common and easy for our HVAC specialists to fix. Another issue that could be indicated by squealing is a faulty motor. Faulty motors are also common, but due to the nature of taking apart and putting together your furnace, it’s best to leave the work to an HVAC professional.

Are You Hearing Any of These Furnace Sounds? Call Moore Home Services.

If you hear any of these sounds coming from your furnace, call Moore Home Services today! Our friendly, expertly trained technicians are experts at finding the best solution for you, the customer. We are Diamond Certified and proudly serve the Santa Rosa and Marin County communities. When you work with Moore Home Services, you can expect to see a technician who is on time, clean, personable, and ready to help. Don’t hesitate, click here to schedule an appointment online, or reach out to our friendly call center representatives.