Why Your Furnace Is Making Strange Noises

20 February 2015
 Categories: , Blog

If you notice a strange sound coming from your furnace, it may be a reason to be concerned. By understanding what those noises mean, you can troubleshoot the problem yourself and determine how to fix it.

Bangs And Booms

If the sound you are hearing is a loud bang or boom right before the furnace turns on, it may be having difficulties igniting. This is often due to a dirty burner.

A burner that is dirty will prevent the furnace from properly igniting. What happens is the gas inside your furnace accumulates, and when the furnace does ignite, it will create a tiny explosion. This is what you hear when there is a loud boom or bang prior to the furnace turning on.

This problem will require the burner to be cleaned, so you may want to hire a professional HVAC technician from a company like Comfort Heating & Air Conditioning, LLC to do it for you.


A rattling sound could be coming from your furnace, or it may be from the ductwork. The best way to tell is to stand near the furnace when it is making that sound. If the sound is emanating from inside the furnace, it may be due to a wheel bearing or damaged belt. If you replace those parts and it is still rattling, the noise may be from a cracked heat exchanger, which is a much more expensive repair.

If the noise is not coming from the furnace, follow the ductwork in your home and try to locate the rattle. It could be from some loose connections in the sheet metal, and all you need is some duct tape to fix it. If the noise is only noticeable in a single room of your home, it may be due to the vent cover. Take off the cover and lubricate the moving parts to stop it from making noise.

Squeals And Squeaks

As your furnace gets older, it will be more prone to being worn down simply due to wear and tear over the years. If the furnace is starting to squeal and squeak more than it has previous years, it could be due to the furnace being old.

A furnace will only last an average of 15 years, with 20 years on the high end. If the furnace is past its prime, the sounds may be telling you that it is time to replace the furnace.

By diagnosing the problem with your furnace, you can determine what the sound means, and how you can take proper action.