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Decoding That Weird Sound Your Furnace Is Making

Inside a gas furnace. Focus = the top of the middle flange. 12MP camera.Winter here in Florida might not mean you’re battling against the coldest conditions possible, but just because we don’t have extreme winters like our neighbors up north doesn’t mean that you don’t need a reliable heater. When you’re running your heater more often through the colder weather, sometimes minor problems have room to become major issues. A really common furnace problem is having odd noises come from your system. If you need help determining why your furnace is making that very peculiar sound whenever it runs, keep reading below; we’ll help you find the cause. If you want the problem fixed, contact our team for furnace repair in Port St. Lucie, FL.

Sounds and Their Meanings

Here’s what your odd furnace sound means:


The sound of metal against metal is never pleasant. If you hear a loud sound like this then you’ve got a problem on your hands. Turn off your furnace and call a professional as soon as possible. If you’re hearing grating, it’s probably because the blower might have come loose, broken, or that the whole assembly is having a problem.


This is probably the most common furnace sound you’ll hear coming from your furnace system. If you hear a rattling sound, it probably indicates a loose part within your system. You need a professional to come to your home and professionally assess your system so they can pinpoint and fix any problems happening in your furnace system.


Yes, rattling is different than rumbling. You might not think so, but these two sounds indicate hugely different problems. While rattling indicates a loose part, rumbling is a different problem entirely. Rumbling is usually indicative of a system that hasn’t been maintained in quite some time. There’s a large opportunity for dirt, dust, and grime to accumulate throughout the system and cause efficiency problems.

A Loud Boom Upon Start-Up

This is another common problem furnace sound. If you’re experiencing this loud and alarming sound whenever your furnace switches on then you likely have a gas build-up problem. A problem like this isn’t one you should ignore. You should always try to contact a professional sooner rather than later for this problem because it can crack the heat exchanger.

Don’t confuse this sound with the sound of your air ducts expanding or contracting when the system operates. This sound isn’t as big of an issue. Your air ducts expanding, or contracting is commonplace. If the noises seem a little too loud or persistent, you should still see a professional. You can either seal or insulate your ducts or clean your air filters.


Squealing, whining, or whistling noises are normally the byproduct of the faulty blower belts, dry or old shaft bearings, or malfunctioning blower motors. Squealing is an issue that you need a professional for, so make sure you call our team as soon as possible.

If you need furnace repair for your home here in Port St. Lucie be sure to contact our team at Speedy Air Conditioning. We have a full team of reliable technicians here in Florida ready to provide quality service for you.

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