Ask Susan, the Heritage Expert!

Ask Susan

The Heritage Consultant

Why Is My Furnace SO LOUD?



Why is my furnace SO LOUD?Why is my furnace SO LOUD? It does a good job heating my home, but it sounds like one of those old two-engine private airplanes revving up for a takeoff. This is just one of the many odd sounds it sometimes makes. Is this a sign that there may be something wrong with my furnace?



Dear Customer,

When your furnace starts making unusual noises, it’s a definite indicator of a problem that needs solving. Let’s see if we can decode the noises first.

Are you hearing a bang, boom, or thud?

If that describes the sound you hear when your furnace turns on, there are a few possibilities. One is that your furnace burners may be dirty. Having dirt on the burners may cause a delay in the burners igniting. Because of this delay, gas will build up which causes the loud bang when it finally ignites. This is not something to ignore, as these small explosions could eventually crack your heat exchanger. If you suspect you have a delayed ignition problem you should call for emergency service.

Another cause of the sound might be your air ducts expanding and contracting as the blower turns on and off and pressure changes. This may be an indicator that the home has undersized ducts, closed vents, or a clogged filter.

Are you hearing a clanging, pinging, popping, or rattling?

The clanging sound could be caused by pipes in the home, as they expand and contract. A pinging or popping sound may be more closely associated with the house’s ductwork. Rattling may be an indicator of loose ductwork, or even of the furnace not being on a solid or level surface. If the rattling is heard as the furnace turns off, this may be the metal parts of the furnace cooling down.

Are you hearing a whistling, or whooshing sound?

These sounds may, again, indicate an issue with the ductwork. Along with the ducts being too small, there may be gaps in the ducts. A dirty filter may also be the cause of these sounds.

Are you hearing a screeching, scraping, or chirping?

If you hear any of these sounds there is a chance that the blower wheel or motor may be the culprit. The blower wheel may have come loose from the motor shaft, the blower wheel may also be broken, or the motor mount may have broken, causing the blower assembly to drop, which has lead to the assembly hitting the furnace casing.

While some of these noises are not necessarily as dangerous as they sound, you definitely need to get the problem fixed as soon as possible. Having annual maintenance performed on your furnace is a good way to stay aware of what is going on, and  stop problems before they start.

Just Call Heritage (or schedule service online!) and make an appointment to have the complete heating system checked. Our trained technicians will be able to quickly tell you which part is making the racket and fix it.


Your Heritage Consultant