Furnace Noises And What They Mean: Guide For Homeowners

Furnace Noises And What They Mean: Guide For Homeowners.

Furnace Noises and What They Mean: Guide For Homeowners

One of the comforts of the cold winter months is knowing that your home will be warm and cozy. But as our furnace ages, the warmth that we enjoy is accompanied by some new and interesting noises that can cause concern. It can be helpful for homeowners to know a bit about furnace noises and what they mean. 

At Broadley’s Plumbing, Heating and Air Conditioning, we have been serving the South Jersey area for over 100 years. In that time we have serviced more than a few furnaces and answered a few questions about furnace noises and potential concerns. That is why I have put together this brief guide on furnace noises and what they mean.

In this blog, I will cover all kinds of noises and help you determine what is a normal furnace noise and identify noises like furnace grinding noises that may cause real concern. Every furnace makes some sort of noise, and not all of them are a bad thing. 

If you are hearing unusual noises coming from your furnace, give us a call at (609) 390-3907, or contact us online. We can come take a look at your heating system and let you know what’s going on! 

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Normal Furnace Noises

It’s normal to hear your furnace kicking on. Most furnaces heat the space, then turn off. Once the temperature drops enough, it kicks back on. It’s not uncommon to hear that turning on and off coming from the furnace. 

Guide to Furnace Noises

I will cover:

  • Booming
  • Buzzing
  • Clanging or Banging
  • Clicking
  • Grinding
  • Popping or Booming
  • Squealing or Whining
  • Thumping or Thwapping
  • Vibrating

Booming

If you hear a “booming” sound when your equipment starts up, it is probably due to delayed ignition.But what is delayed ignition, and how does it happen? The short answer is that something is preventing the gas in your furnace from igniting (lighting up) right away.

Delayed ignition is a condition that should be addressed by a qualified service technician. It is – in essence – a “mini” explosion caused by a buildup of gas within your furnace that over time can put strain on the heat exchanger which is one of the more costly parts to repair.

You see this with grills at times, when you let the gas run but it doesn’t light up right away. Then once it does, there’s a big flame initially. The same thing applies here. 

Buzzing

There are a few possible reasons why your furnace makes a buzzing noise. The most common reason is if the mount of the transformer comes loose. In that case it may produce a buzzing noise as the furnace starts up.

A loose transformer box is commonly to blame when the furnace has been recently installed. On older furnaces, a buzzing or loud humming noise likely means the transformer needs to be replaced.

Some other causes are a bad capacitor or a bad blower motor. 

The furnace’s capacitor stores electricity to help its motor start up when a heating cycle is called for by the thermostat. If the capacitor goes bad you will hear a buzzing sound.

The same holds true for the blower motor. If the blower motor is failing, you will hear a buzzing sound.

Clanging or Banging

Sometimes Ductwork Can Be The Cause Of Your Clanging And Banging Noises.

Clanging or banging noises will often happen because of ductwork expansion. Air pressure buildup within your HVAC system can push against the walls of the ducts, causing them to expand.

While these noises may sound concerning, they are usually harmless as they are a natural part of duct expansion.

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 Clicking

Clicking noises can be cause for concern. In the case of a gas furnace they can indicate a broken, jammed or clogged gas valve.

In the case of an electric furnace some components that are part of the starter system can fail creating strange clicking noises. Since it is an electrical furnace you don’t need to worry about gas leaks but it does require professional attention.

Grinding

The most likely cause is that the blower fan is loose or broken. A loose fan can grind against the housing when in operation. A broken bolt or similar piece of hardware can sometimes get lodged in the blower fan or motor, causing that horrible metal-on-metal grind.

Popping or Booming

If your furnace makes furnace makes popping noise when turning on, it could be coming from gas build up due to dirt or debris or other organic matter getting into your furnace. The buildup of debris can cause a popping noise to occur when the flame ignites.

Another reason for popping can be from metal ductwork expansion, like we mentioned before. 

Squealing or Whining

Worn-out blower motor bearings are a major cause of the furnace blower squealing. This happens as the bearings wear out from the continuous friction of the blower motor during operation. If this is the case with your furnace, the solution would be to replace the bearings.

Thumping or Thwapping

Thumping or Thwapping usually indicates a problem with the blower motor.

A loud, regular thump or thud that sounds continuously as your furnace is running is probably an unbalanced blower wheel or motor. You’ll hear the sound of the rotation as the wheel or motor whirls unevenly in your system. You should have the part balanced as quickly as possible to avoid further damage.

Thwapping

Thwapping noises may indicate that some kind of debris is stuck in the fan of your blower motor. In both cases – thumping or thwapping – a service call is warranted.

Vibrating

There Are Lots Of Components That Go Into Your Furnace Operation.

Vibration of any kind usually indicates that something is loose. But there are a few other causes of vibrations. Loose parts, blower wheel issues, fan motor problems, dirty air filters, ductwork problems, expansion and contraction of ductwork, and ignition problems are some of the reasons why your furnace may vibrate when starting. 

Furnace Noises FAQs

If you have experienced any of the noises that I have outlined above and are looking to fix your furnace in Avalon, NJ, Broadley’s is only a click away to help you identify and solve your furnace concerns. Give us a call at (609) 390-3907, or click here to contact us online

Should you be able to hear your furnace?

Hearing the rush of air or a low hum is completely normal. Any unusual noise deserves a service call to head off bigger problems.

Are newer furnaces quieter?

Most new furnaces are quieter than older systems. That said, each manufacturer has different levels of quiet. Always ask your technician for advice. Their experience is invaluable here.

What does a bad condenser sound like?

A bad furnace condenser can make a buzzing noise. But a buzzing noise can also be caused by some other faulty electrical part. Always call in a licensed technician to accurately identify the problem.

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