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Furnace Sounds That Should Not be Ignored

As a reputable provider of furnace repair services in Polk County, IA, we want to educate our customers on furnace sounds that signal a problem. Early detection is paramount if home and business owners want to avoid hefty maintenance and repair costs. Below is a list of furnace sounds that shouldn’t be ignored.

Metal Against Metal

Scraping or clanking noises could signal a severe problem with the blower wheel inside your furnace. If you hear these sounds, turn off your heater instantly and call an HVAC technician so they can inspect the system. Clanking is often a sign that the blower fan is coming loose. If the fan or wheel isn’t too damaged, repairs should be easy and quick.

If the blower fan has broken, it may need professional replacement. Either way, a professional diagnosis is recommended.


Rumbling sounds usually indicate that a furnace has not been professionally maintained for a while. Gas burners become dirty over time, and pilot lights often need adjusting. If the furnace flame is blue, it indicates that a burn is efficient and clean. If the fire burns orange, yellow, red, purple, or green, call an HVAC professional. These colors often indicate a potentially hazardous and inefficient working condition.


Rattling noises coming from a furnace can be an indication of a loose screw or panel. Before working to identify and fix this problem, always turn the power off at the source. We recommend tightening up the panel with a screwdriver to see if this fixes the rattling sound.

If the noise continues, this could indicate a crack or leak in the heat exchanger, which can be lethal. Broken heat exchangers can leak carbon monoxide into a home or commercial space. If you cannot solve the source of the rattling sounds by tightening up the panel screws, call an HVAC professional immediately.

Screeching or Squealing

Loose or damaged blower belts can cause squealing or screeching noises in belt-driven motors. Also, moving parts such as shaft bearings may have become dry and require lubricating. Finally, malfunctioning blowers may be the source of screeching sounds.

Whatever the case, scheduling a professional inspection will ensure that your furnace is tuned-up and optimized for safety and efficiency.

To schedule an inspection, or for sump pump installation in Polk County, IA, click here to contact Lazer Home Services today.