Why Is My Furnace Making That Noise? 4 Common Answers

No one wants to hear unsettling noises from their furnace. Here are four of the most common reasons for furnace noises that you'll want taken care of. 

1. Delayed Ignition

One of the most common noises made by an unhappy furnace is heard only when it starts to turn on. Delayed ignition causes a loud boom or bang as the furnace starts up, which can be startling in the middle of an otherwise quiet winter evening. 

This boom is happening because of oil or gas buildup within the furnace's firebox chamber. When the compiled oil or gas is suddenly ignited, the resulting explosion reverberates with an audible boom. Just as it sounds, it can be dangerous, and you need a furnace repair professional to address the problem. 

2. Leaking Duct

If you hear a faint or high-pitched whistling while the furnace is running, it could mean there is a gap or crack in the ductwork somewhere. The air escaping creates an annoying whistling that you'll be able to hear right next to the duct. A vibration sound could also be caused by a leaking duct. 

Clogged filters can also cause this noise as the filter works harder to suck in air. By getting close to the ductwork and filters, you should be able to tell where the noise is originating to help diagnose the exact issue. 

3. Dry Belt or Bearing

A squealing or squeaky furnace could be trying to tell you its belts or bearings are in need of lubrication. Just like any other engine, furnace parts need to be well oiled in order to move smoothly and quietly. 

A furnace technician can easily add lubrication to belts and bearings that have become dry over time. It's better to take care of this sooner rather than later to avoid dust or dirt causing further irritation and damage to these moving parts. 

4. Loose Parts

Noises like clicking, rattling, or rumbling in a furnace can mean parts are loose or need to be tuned. Even small pieces like nuts and bolts can come loose over time and create loud rumbles while the furnace is running. 

Heat exchangers and ignition problems can also cause these noises, so it's best to have a furnace maintenance professional take a look to find out if a serious repair or simple tune-up is needed. If ignored, loose nuts and bolts can fall out and necessitate a much bigger repair.

Call a heating service for more information or assistance.