Furnace Noises: What Causes Them and How to Deal With Them

Continuous banging or popping noises in a furnace may signal dirt buildup or ductwork expanding and contracting due to temperature changes. Neglecting cleaning can lead to gas combustion issues and heat exchanger damage.

A home furnace isn’t exactly the most silent piece of equipment, which is why it can be challenging to determine if the sounds it makes are normal or indicate a problem. Distinguishing a minor issue from one that requires the urgent attention of an HVAC technician can also be difficult. When squealing, banging, thumping, or wheezing noises occur whenever the furnace is turned on or in operation, contacting a local heating and cooling services contractor as soon as possible is advisable. Delaying this can cause the problem to persist, increasing the chances of it becoming costly to fix.

The Meaning Behind Strange Furnace Noises

The following are some of the unusual noises that a furnace may make and their meanings:

Banging Noises

A continuous banging or popping noise inside the furnace could signal one of several problems. For instance, the heating unit may have accumulated too much dirt. If not removed immediately during a routine maintenance check, gas combustion issues may ensue, resulting in various problems like cracks and splinters on the heat exchanger or an ignition delay. The ductwork may also be experiencing expansion and contraction during cold weather. The sheet metal contracts at low temperatures and expands when the furnace turns on, causing stress at the duct seams, which makes the metal buckle outward and produce a banging noise.

Scraping Noises

A loud scraping noise inside the furnace could mean the blower wheel has moved out of alignment and is hitting the blower house casing repeatedly. The grinding sound of metal against metal should signal that the heating equipment should be turned off, and a technician should be called to fix the issue.

Rattling Noises

Rattling noises from a furnace are usually not too worrisome and can often be fixed easily. Loose fittings, for example, are common, especially if the heating unit is used regularly during the winter months. Tightening the screws should stop the annoying noises. The blower fan and motor may also have inadequate lubrication. These internal parts push air through the ductwork, causing a lot of noise. If the noise becomes unusually loud, it indicates that lubrication is needed.

Squealing Noises

Squealing is a typical furnace noise that signifies the need for a minor tune-up. Most likely, a faulty drive belt needs adjusting or replacing. It could also mean that the blower motor’s bearings have worn out. To accurately pinpoint the source of the noise, contacting a local heating services technician as soon as possible is recommended.

Whistling Noises

Several issues could cause a furnace to produce whistling noises. One reason might be tiny gaps in the ductwork. Whistling may be heard from a small hole near the point where the ductwork and the furnace connect, particularly close to the blower. Another cause could be dust and dirt clogging the furnace filter, forcing the fan to suck air from anywhere it can. Removing the filter to check if the noise stops is advisable. If the filter is too dirty, replacing it will not only stop the noise but also prevent the furnace’s fan motor from wearing down.

Noisy Furnace: Is It a Serious Problem?

Ignoring a loud furnace is never a good idea, no matter how tempting it may be. Any time this happens, something is going wrong inside the unit. Depending on the issue, a large range of problems might require immediate attention.

A noisy furnace operates inefficiently. Although it may not seem hazardous, it can still be problematic. Ignoring these noises for a long time will cause the unit to expend too much energy to keep the home comfortable, shortening its expected lifespan and causing heating bills to skyrocket, thus wasting precious amounts of fuel.

A noisy furnace can indicate more issues in the future. For instance, a loose blower belt may start as a minor issue but will eventually work itself looser until the fan stops working. The furnace will then stop working unexpectedly, which is undesirable during the cold winter months. Addressing such problems immediately with inspections and repairs minimizes the chances of the heating equipment’s working parts getting damaged and requiring replacement.

In some instances, a loud furnace can become a threat to occupants. Remember that it utilizes combustion to provide indoor comfort whenever the weather is cold outside. When something goes wrong, there is a significant risk of injuries and property damage. Delayed ignition due to excess dirt buildup inside the furnace, especially on the burners, can cause gas to build up to such high levels that an explosion or fire could occur. Additionally, a loose exhaust pipe or damaged heat exchanger can cause carbon monoxide to leak indoors.

Dealing With a Loud Furnace

A loud furnace can be fixed with a bit of troubleshooting. Check the access panel to ensure all screws and fittings are properly tightened and secured. For safety and continued performance, it is in the best interest of the homeowner to contact a certified contractor specializing in HVAC repairs and installations. The technician can locate the source of the noise and perform repairs to get the equipment running smoothly again. They may, however, recommend replacing the entire system if it is close to the end of its lifespan.

Fix My Air DFW of Fort Worth specializes in residential and commercial HVAC services, including routine maintenance, installation, and repair. All makes/models. Call us at (817)839-3511.