Common Furnace Noises and What They Mean

Furnace Noises and What They Mean

When you’re relaxing, a noisy furnace can ruin your peace at home. These noises may sound scary, but they are often early warning signs of bigger problems. Here are some examples of common furnace noises and what they may mean:

Popping or Banging at Start-Up

Like a misfiring engine, you might hear banging or popping sounds when your furnace starts up, which is not normal. If this happens, it could be that your furnace burner needs cleaning.

inside view of a furnace: common furnace noises and what they mean

Dust, dirt, and other organic matter quickly get into your furnace and cause gas to build up. The burner then struggles to reach a hot temperature and combust a fuel. And, when the burner gets hot enough, it pops because of the excess gas or oil.

Do you also hear these sounds when the unit cycles off? In this case, it might be the ducts popping as they expand or contract with temperature changes. It is entirely normal, but if it’s annoying to live with, ductwork maintenance can alleviate this problem.

Scraping Sounds

A metal scraping sound from the furnace may mean you need to schedule an appointment with an HVAC technician. The scraping noise is usually because of one of two things.

  • It could be that the blower wheel is broken, so the wheel scrapes all over other metal components.
  • Another reason is that the motor mount is broken and the blower wheel is tumbling all over your furnace.

Neither of these problems should be neglected because they could cause damage to other furnace parts.

Whining or Squealing

You might hear a high-pitched squeal from your furnace. Despite what you think you heard, it’s probably not an animal. It’s the blower belt that is worn out, misaligned, or in need of lubrication. The furnace might need a quick tune-up and cleaning to remove grime and inspect for broken or failing parts. You might as well call a furnace repair technician for this because it’s more complicated than you might think.


 A wheezing sound from your furnace may startle you, especially in the middle of the night, but don’t be alarmed. It's probably not that big of a deal. If you forgot to change your air filter, a wheezy HVAC system is an indicator that the filter needs replacing. The sound is just the treated air trying to make it through a filter that is full of particulates.


A clicking sound from your furnace may be annoying, but it is better to be aware of a potential issue and confront the annoyance. This sound may come from the furnace ignitor or heat exchanger, and it's possible the faulty part needs replacement. If those parts are working fine, your furnace might just need a tune-up.

Get Furnace Parts at PlumbersStock

Whatever part you need, you can find high-quality products here are PlumbersStock. We have all the HVAC parts you need, including furnace ignitors, blowers, blower wheels, and more. Did you know that you can find member pricing here on specific items (typically name brand, MAP priced items) if you log in? For industry professionals buying in bulk, please consider contacting us directly for extra special pricing and extra savings.

Related resources:
Quiet a Noisy Furnace Blower
Can You Bypass a Flame Sensor?
How to Bypass Furnace Pressure Switch
Furnace Pressure Switch Stuck
How to Tell If a Blower Motor Is Bad
How to Tell If CO Is Leaking

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