During this time of year, our furnaces are working hard around the clock.  In fact, they work overtime to ensure the warm air stays circulating throughout our homes. 

But what if your furnace begins making strange noises?  A loud humming noise, a rattling or grinding, or even a loud boom?  These noises can be a sign that your furnace may be malfunctioning and shouldn’t be ignored.  It could be an issue of simple maintenance or could suggest a repair or replacement of a part.  Let’s examine each odd noise and identify potential causes or remedies.

Humming: A loud, humming noise is most likely an indicator that your furnace’s motor is on the fritz.  The buzzing could also mean the motor is on its way out.  But if you notice the noise when the motor is slowing down, it’s most likely an amperage problem, which can happen when there is damage to a part of the furnace.

Rattling: A rattling sound could simply mean that a component of the furnace is coming loose.  Simply repairing or tightening the part can help avoid a costly repair or replacement.  Unfortunately, a rattling sound can also mean that your furnace has a cracked heat exchanger.  Carbon monoxide leaks can be caused when the heat exchanger is cracked, so it’s important to figure out the issue quickly and replace the damaged part as soon as possible.

Boom!:  That sound can be scary when it comes from your furnace.  The most likely culprit is the expanding and contracting of the metal ductwork when the furnace’s blower starts up.  Likely causes of an air duct’s expansion or contraction are dirty air filters and closed air vents and dampers.   So changing the furnace’s air filter, and making sure your supply vents are open, can help remedy the problem.

Bang: If your gas ignition is delayed, you may hear a loud bang when your furnace turns on. This happens when the gas in your furnace builds up rather than immediately igniting.  Then, when the furnace finally ignites, it causes a mini-explosion – which could seriously harm your furnace.  If this happens, it’s best to have a professional inspection. Always better safe than sorry!

Strange noises coming from your furnace can certainly be a cause for concern.  It could be a minor problem, remedied by a small tweak, or it could indicate larger problems with your furnace.  Remember, when in doubt, call a heating professional.  An expert can ensure your furnace is running correctly and efficiently, ensuring your home not only stays cozy, but safe as well.