A noisy furnace is more than just a nuisance; it may indicate a serious problem with your home’s central heating system. To protect your furnace from premature wear and tear, you should listen to it. The following noises may indicate an underlying problem that requires immediate attention.
A rattling noise typically means something is loose. It may be something as simple as a loose panel. If there’s a removable panel on your furnace that’s loose, you may hear a rattling noise. Alternatively, a rattling noise may indicate one or more loose fasteners. Furnaces, as well as the blowers with which they are used, contain many different fasteners. And it only takes a single loose fastener to create a rattling noise.
If you hear a banging noise when your furnace initially turns on, you may be dealing with a broken or cracked heat exchanger. Gas furnaces use a heat exchanger to create warm air. They burn natural gas in a combustion chamber, which in turn creates hot exhaust gases. The hot exhaust gases then travel through a sealed heat exchanger that’s exposed to a blower.
Heat exchangers may crack. Rather than offering a sealed environment for the hot exhaust gases, a cracked heat exchanger will allow these gases to leak. You may hear a loud banging noise each time your furnace turns on if it has a cracked heat exchanger.
Furnaces often make grinding noises as well. If you hear a grinding noise when running your furnace, you may want to get the blower professionally inspected. A faulty blower wheel can manifest in the form of a grinding noise.
The blower wheel, of course, is the main, circular-shaped part of a blower. As it turns, it will force air into the ductwork. If the blower wheel has become misaligned or otherwise not properly positioned, you may hear a grinding noise when running your furnace.
Your furnace may make a whistling noise if there’s an airflow problem. A dirty air filter can manifest in the form of a whistling noise. Little or no air will be able to pass through the dirty air filter, so you may hear a whistling noise originating from this area.
Another potential source of a whistling noise is an air duct leak. If there’s a hole in an air duct, you may hear a whistling noise as the air leaks out of it.