Now that the temperatures have dropped, it is quite likely that you are using that furnace in your home a bit more than you have for most of the year. Yes, a little noise here and there is common and most of the time, nothing to be concerned over; however, if you are reading this, it is likely that your furnace is making significantly more noise than usual. The bad news is, there could be an issue. The good news is, the type of sound you are hearing typically indicates the underlying problem. Continue reading to learn more.

woman listening to furnace noises

1. Banging Noises

When you first start your furnace for the year to help increase the temperature in your home, you may hear a banging sound. This is a bit common at the initial start-up before winter because the burner likely is a bit dirty. This area is prone to the accumulation of dirt and debris.

When these substances are present, the gas builds up and when the flame gets to the point of ignition, there may be a banging, popping, or even a boom-like noise. To avoid this issue, clean the burner well. If you have cleaned the burner and continue hearing the noise, move on to the next step.

The next issue that could cause banging sounds is an ignition issue. It could cause gas to accumulate within the combustion chamber. When this happens and there is enough gas, a banging sound may occur. This could stem from low gas pressure, a weak flame, or a problem with an electronic-based ignition.

The final issue that could be causing banging noises is the ductwork. The thin metal that makes up the ductwork could be expanding and contracting due to the heat flowing through the system. The resolution is to transition to round ductwork or replace it with ductwork composed of thicker metal.

2. Whistling Noises

If you hear a whistling-like noise coming from your furnace, this indicates that there is an interference associated with the air that is flowing within the system.

It could be something as simple as a dirty air filter that needs to be cleaned or replaced or there could be obstructions in the ductwork.

Other common issues include a return that has a blockage, vents that are closed, or dampers that are closed. The worst-case scenarios are problems with the blower in the furnace or the burners.

3. Knocking Noises

If you hear a knocking noise, this is not normal. It typically indicates a problem with the system’s fan. It could be that the unit has become completely misaligned or that the blades are coming into contact with other components of the system.

Additionally, it could indicate that the fan belt is either cracked or has split. Once this happens, it may hit other parts of the system as the fan attempts to go through the rotation cycle.

4. Humming Noises

Once a burner ignites on a furnace, it is common for the entire system to hum. This typically indicates the unit is running. In other cases, it could be a transformer. It has to go through the process of adjusting the current for the system – as a whole.

If it sounds as if the noise is coming from the motor, this could indicate a problem with that motor. The fan of a furnace may also hum when it is worn down.

If it only occurs when the unit turns on, it is likely nothing that you need to be concerned about. If it happens as the system continues to operate, it is time to call a specialist.

5. Rumbling Noises

Whenever a furnace turns on, you will hear a bit of a roaring sound. If this sound – eventually – turns into a rumbling noise, it is a cause for concern.

This could indicate that there is an issue with the actual burner component of the system. Most commonly, the oil or the gas remains trapped within the combustion chamber.

It will continue burning – even when the unit is not on. If this happens, turn the furnace off immediately as this could result in carbon monoxide accumulating within your home. You will need immediate assistance from a certified technician to resolve this problem. Allowing the system to operate could put you, your loved ones, and your pet or pets in danger.

6. Scraping Sounds

A scraping sound will resemble that of metal on metal. This could indicate that the blower fan is loose or that the blades of the fan are actually dragging across the casing of the unit.

If it sounds like metal scraping against metal, you should turn the unit off and contact a professional immediately. Allowing it to continue to run could result in serious damage to the entire system and even to your home.

7. Rattling Noises

If your furnace turns on and you start to hear rattling noises, it is likely the air ducts. Sometimes, this is something as simple as the duct being a bit smaller than the opening of the vent that it flows through. In other instances, it could indicate that something within the duct – such as the joints – are loose. The only real danger with this is that you are likely losing a significant amount of heat through that which is loose. For your comfort and to avoid costly heating bills, you should contact a professional immediately to have the issue dealt with quickly.

Quick Solutions

Hearing a noise in your furnace is not a pleasant experience; however, some noises are completely normal. To ensure that you experience as few issues as possible, do the following:

  1. Before lighting the system for the first time, ensure that the burner is completely cleaned.
  2. Throughout the year, have the furnace evaluated by a professional to determine if any tune-ups or other types of maintenance are required. During this time, the components will be evaluated for proper functionality and will be cleaned.
  3. Make sure that you change the air filter of your furnace regularly – especially during the times of the year that you use it most.
  4. Evaluate your ductwork or have it inspected regularly. If it becomes loose, develops space between edges, or any other issue, the technician that inspects the ductwork can handle it immediately.
  5. Prior to turning on the system for the first time for the year, go through the home and make sure that all of the vents and associated dampers of the system are opened. Failure to do so could result in those troublesome whistling noises previously mentioned.

Contact Us Today

We can inspect, maintain, repair, and/or replace your furnace. We recommend that you set up a regular maintenance plan throughout the year so that when it is time to warm up the inside of your home, you are not caught in the cold! In addition to top-quality heating and air services, we also specialize in plumbing. Regardless of what type of issue you are experiencing with your heating, air, or plumbing, we can assist you! We have assisted individuals in Wayne County for over 30 years. Set up an appointment, contact us today.

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