Frightening Furnace Noises and HVAC Fixes

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Frightening Furnace Noises and HVAC Fixes

It’s that time of year. You know, things that go bump in the night. The eerie sounds of ghosts and goblins, or at least people dressed like ghosts and goblins. The sounds of Halloween may not scare you, but the scary sounds coming from the furnace in your Illinois or Northwest Indiana home might make you a little concerned.

When to get concerned

Everyone knows furnaces, or any type of forced air heating system, is going to make some noise. There are fans, blowers, and motors all making noise. If the sound is something new or strange, then the concern meter should go a little higher. Here are some types of sounds to be especially aware of:

Scraping noises:

  • Sometimes this is because of metal-on-metal contact caused by a faulty blower wheel. Don’t procrastinate on this as it could cause serious damage and requires attention by a trained HVAC technician.

Loud pops or bangs:

  • These can be caused by a dirty furnace burner. As dirt collects on the burner, it causes delayed ignition leading to gas buildup. When the burner finally ignites, you hear a loud pop or bang.
  • These small explosions sound scary and can damage your furnace. One result can be a cracked heat exchanger, a leading cause of deadly carbon monoxide poisoning.

Squealing noises:

  • This isn’t exactly fingernails on a blackboard, but it can be close. A high-pitched squealing noise generally indicates something needs to be replaced. To avoid any further damage or breakdowns you should call your HVAC company.


  • Hissing is almost always a sign air is escaping from the system. If you hear it coming from the walls when the furnace is running, it’s a clear sign you need duct sealing or repair.
  • If the sound is coming directly from the furnace, it could mean your filter is not installed correctly or is the wrong size.

Not every noise is a concern

It’s not unusual to hear some strange noises when you first start using the furnace in the fall. The equipment has been idle for months and needs time to work out the mechanical kinks. So, when you turn it on for the first time don’t panic if you hear scary furnace sounds unless they don’t go away in a matter of a day or two.

We are here to help

The best way to prevent any problems, including strange sounds, is by having regular preventive maintenance performed on your heating and cooling systems. Merts Heating & Air Conditioning is the HVAC company you can count on for the same quality and honesty we’ve been delivering to the people of Illinois and Northwest Indiana since 1952. Be sure to like and follow us on Facebook and Twitter for more great information.