Causes of Loud Sounds in Your Furnace

October 20, 2022
Furnace in Deptford Township, NJ

Modern furnaces are designed to operate more quietly than ever before. However, you should not ignore it if your furnace makes loud noises. Usually, loud sounds indicate a more severe problem or damage to the unit. Different parts of the furnace system can produce different sounds. No matter the cause, you’ll want to bring in one of the professionals from JAMCO Heating & Air Conditioning. We’ve been serving Deptford Township and all of South Jersey and southeastern Pennsylvania since 1986.

Dirty Furnace Filter

A furnace filter helps to remove airborne particles, like dust and dirt, from the air as it circulates through your home. However, over time, the filter becomes clogged with debris, which can restrict airflow and cause your furnace to work harder than necessary to heat your home.

You might hear an eerie whistling sound of air trying desperately to get through the furnace system. Changing your filter once a month is a good idea, especially in the winter. Otherwise, the clogged filter will restrict the air and increase the chances of the furnace motor or heat exchanger being seriously damaged, and a dirty filter can compromise your home’s air quality.

Damaged Blower Motor

One possible reason that your furnace makes loud noises could be a damaged blower motor, which is the component that is responsible for pushing air through the ductwork in your furnace. If it becomes damaged, it can cause your furnace to make loud screeching and rattling noises when you turn it on. The damage could be caused by inadequate lubrication of the bearings in the motor blower. Like a bike chain, the bearings need to be oiled every so often.

Loose Blower Belt

Your furnace may be noisy if the blower belt is loose. The blower belt is a large belt that goes around the blower wheel, which helps move hot air through the furnace and into your ductwork. If the belt is loose, it can cause the wheel to spin erratically, resulting in a banging or knocking sound. Additionally, if the belt is loose, it can cause the wheel to rub against other parts of the furnace, creating a grinding noise.

Cracked Heat Exchanger

The furnace may be producing loud noises because of a cracked heat exchanger. The heat exchanger is responsible for transferring heat from the combustion chamber to the air circulated throughout your home. If there is a crack in the heat exchanger, hot gases can escape and come into contact with the metal surfaces of the furnace, resulting in a loud banging or rattling noise.

Additionally, the heat exchanger can make popping noises as the gas ignites, which could indicate the presence of a crack. In some cases, a cracked heat exchanger can lead to the escape of deadly carbon monoxide fumes into your home. The primary cause of a crack in the heat exchanger is the lack of airflow. Restricted airflow results in the building up of heat within the heat exchanger, which can cause cracks and splinters.

Dirty Burners

If your furnace makes a loud banging noise, dirty burners are the most likely culprit. The burner mixes fuel with air and creates a flame. Over time, dirt and debris can build up on the burner heads, causing them to misfire. When this happens, the flames that should be burning evenly instead hit the sides of the chamber, creating a loud banging noise. Dirty burners delay the ignition process of your furnace, building up the gases leading to an explosion sound when the ignition is turned on.

Flexing Ductwork

When the furnace kicks on, the sudden blast of hot air can cause the ductwork to expand and make noise because of the differences in temperature and pressure between the air inside the ducts and the air that’s outside. This is especially common in homes with forced-air heating as the ducts are often routed through unheated areas such as attics or crawlspaces.

Loose Hardware

If your furnace is unusually loud, it could signal that your nuts, bolts, bindings, or moldings could be loose. Over time, vibrations from the furnace can cause screws and bolts to work their way loose. As a result, the metal components of the furnace will start to rattle against each other, producing a loud noise. To avoid these problems, check the hardware on your furnace regularly and tighten any loose screws or bolts before they fall off. Your technician from JAMCO Heating & Air Conditioning can also take care of this during your yearly maintenance visit.

Furnaces are an essential part of any home, but if they are not regularly checked and maintained, they can be noisy. Ignoring the loud sounds could lead to expensive repairs down the road. If your furnace is loud, or you need residential installation, commercial services, or ductless mini-splits services, contact us at JAMCO Heating & Air Conditioning to schedule an appointment with one of our experts.

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