furnace hvac services - furnace noises

Noises You Don’t Want Coming from Your Furnace


It is a common thing for a furnace to make noises. After all, it is a machine. However, there are noises that you should not ignore once you hear them. If you do, they can prompt you to do an expensive repair or a replacement. These noises are as described in the paragraphs below.

1. Screeching

If your machine makes a screeching noise, its blower motor is not functioning well. It could be due to the wear and tear of its bearings which leads to increased friction between them. When that happens, the circulation of warm air in your house will be compromised.

Fixing this problem requires that you lubricate the bearings. They will start moving smoothly again. However, it can be catastrophic if you ignore it since the motor will burn out due to overheating. And it may lead to the whole furnace breaking down.

2. Banging

This noise is common with old furnaces that are not being maintained well by doing yearly checks. If you hear such a loud bang from your furnace, it is vital to do HVAC services immediately because it could be indicating a hazardous scenario. It could mean that the grime and dirt on the burners have collected gas that suddenly burns.

It is dangerous because the bang can destroy the heat exchanger. As a result, your house could be exposed to carbon monoxide gas, which is harmful. The most unfortunate thing about this gas is that it is odorless and colorless. So, it is easy to suffer its consequences.

3. Rattling

When you hear a rattling sound, it means there is a part of your machine that has broken loose and is now moving around carelessly. It may not be dangerous, but it may impact other parts, causing harm. For instance, if the heat exchange is affected, it may lead to a carbon monoxide problem, as already mentioned above.

The wise thing to do here is to switch off the furnace and call an expert to conduct HVAC services on it.

4. Silence

As stated earlier on, furnaces should make some normal noise. It indicates that they are running smoothly. So, when it hits you with sudden silence, then there is a problem. It could be that the heater has malfunctioned and needs either a repair or a replacement. HVAC services come in handy when such a thing happens.

5. Clanking

The clanking sound resembles that of metal hitting another metal. Furnaces occasionally make this type of noise, and there is no cause for an alarm. However, when it occurs more often, there is a problem, and you will be forced to do an expensive repair. That is because the blower wheel may have been damaged. In a worst-case scenario, you will need to replace the whole system.

6. Squealing

This is a noise you should expect from animals only. Not your home furnace. However, if you hear it, there is a problem that needs fixing. It could either be damaged bearings or a worn-out belt. The belt can only be replaced, but the bearings can be repaired or replaced. A professional can help you with either.

7. Whistling

A whistling noise can be caused by improper airflow in your furnace. All you should do to correct this mess is replace or clean the air filters. The other possible reason for this is closed vents. You should also have a professional check on them and make appropriate adjustments to start running well again.

8. Rumbling Sound

When you switch the furnace on, it should make a harmless roar as it starts. However, if the roar persists and starts to sound like a rumble, that is a sign that its burner has a problem. You should act first and have it checked before further damage is done.

9. Gurgling Sound

The boiler baseboards are the most likely place for this sound to emerge from. It is caused by air in hydronic heating lines, which should not be the case. So, it is crucial to call upon a professional to look at them critically whenever you hear them.


The above-described noises are an indication that your furnace is experiencing some malfunction. Please do not wait, have it checked immediately.

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