Like everything mechanical, it’s completely natural for your heating system to make noise as it runs. However, there is a difference between normal furnace noises and those that spell trouble. The pros at New Berlin Heating & Air Conditioning are here to help you tell the good from the bad and to help get your system back on track. We’ve sharing our expert insight below—and if your system needs repair, don’t hesitate to call us at 262-784-8889.

What Does a Healthy Furnace Sound Like?

A healthy furnace will give off a low hum as it operates—this is the sound of the fan as it circulates warm air. If you have a gas-powered system, you may also hear a pop or a click when it starts up, which is simply the sound of the unit igniting. Older furnaces may hum louder when they run, but if you don’t hear anything out of the ordinary (such as any of the sounds below), you won’t have to worry about a potential breakdown.

Furnace Noises You Shouldn’t Ignore

If your furnace makes one of these strange or sudden sounds, you should have one of our professionals look at it:


Grinding or scraping usually indicates a problem with the unit’s blower wheel. Whether the fan came loose and is hitting other metal parts inside or the motor’s bearings are dry, a repair can be quick and easy (provided the parts aren’t damaged). A good way to prevent this is to schedule regular system maintenance—this simple service helps make sure all parts are working, attached, and lubricated.


There are a couple issues that could cause your furnace to make a rattling sound. Best case scenario: It’s as minor as a loose panel or a screw that’s shaking back and forth as the furnace runs. However, rattling could also mean there’s a leak or crack in your heat exchanger, which is a much more serious problem. To be safe, turn off your system and call in an expert right away to inspect it.

Loud Boom or Bang

If you hear a big boom coming from your furnace, turn the unit off immediately and call in our experts. Whether from dirty burners causing a delayed ignition or expanding and contracting ducts, loud bangs usually stem from a gas build-up somewhere in your system. It’s important to call for help when you hear this—the blockage can crack your heat exchanger and lead to a gas leak in your home.

For All Strange HVAC Noises, Turn to the Experts at Carrier® and New Berlin Heating

No matter what problem your furnace is facing, you can always count on New Berlin Heating to help you set it right. Our techs specialize in heating and cooling repair, whether you have a Carrier® furnace or air conditioner. Contact us today for better home comfort—call 262-784-8889.