4 Causes of Buzzing Noises in Furnaces

NoisesWe all know what a functioning furnace sounds like, right? Well, maybe not, but your heating system will typically make a dull hum and blow quietly throughout its heating cycle. You may also hear your unit click on and off. Again, this is a sign of normal operation and is no cause for concern. However, you may be alarmed if your furnace starts to produce a buzzing noise when it’s running. This may be an indication of a faulty component or abnormality in the ventilation.

If you don’t know why your system is buzzing, we recommend seeking the advice of a professional technician to assess the issue. To help you determine the location of the buzzing sound in your furnace, we have compiled a list of 4 types of issues that may be related to the sounds you are hearing.

Why Is My Furnace Making a Buzzing Noise When It’s Running?

1. Malfunctioning Transformer Box

A component within your furnace that alters incoming volts to align with that of your system is called a transformer. If this part of the system is loose due to poor installation or has significantly aged, your furnace will begin to generate a buzzing noise when it’s running.

2. Defective Capacitor

A faulty capacitor is another reason why your furnace will make loud buzzing sounds. When initiated by the thermostat, your capacitor kick starts your heat cycle with stored electricity. When operating correctly, your furnace’s capacitor is likely inaudible. However, loud and constant buzzing may signal immediate repairs are needed.

3. Inadequate Blower Motor

The blower motor is responsible for distributing warm air through the ventilation system of your living space. If the blower motor in your furnace is inadequately performing, you will hear buzzing noises when your furnace is running. This may indicate the need for a small repair, or that the entire motor is failing.

4. Loose Air Ducts

If you believe buzzing noises are coming from the vents of your home or business instead of the furnace itself, the ductwork is likely loose. Over time, high-pressured air blowing through the ventilation can spring metal sections of your HVAC loose and cause them to vibrate against another component, generating a buzz.

High-Efficiency FurnaceWhy Furnace Buzzing Sounds Need To Be Fixed By a Professional

In a world where everything is DIY, resolving your furnace’s buzzing issues are not. If your furnace makes a buzzing noise when running, you need to contact an HVAC professional. While you may know which part the sounds are coming from, you may severely injure yourself attempting to fix the malfunction or replace a component of your furnace. If you attempt to fix the buzzing noise in your furnace without a licensed technician, you may cause a variety of hazards:

  • Make the issue worse
  • “Fix” the wrong component
  • Electrocute yourself
  • Use of wrong materials
  • Start a fire
  • Cause system failure

To avoid these hazards and others, please contact a furnace technician to eliminate your furnace buzzing sounds.

3 Other Types of Furnace Sounds

If your furnace isn’t buzzing but it’s making an unusual noise, you’ll want to first determine the type of noise as well as the cause.

Loud Banging Noises

A loud bang or boom noise coming from your heating system should never be ignored. Similar to a gunshot, this sound is likely caused by a buildup of gas within your unit.

When your unit hasn’t been serviced in several seasons, your furnace’s burners will become increasingly dirty and cause gas to seemingly combust when your system’s heating cycle starts. If this happens, immediately power down your system and contact a professional for immediate service.

NOiseRattling Sounds

Rattling is perhaps the least or most worrisome sound a furnace will make. Most often, this sound is typically caused by a loose panel, screw, or part. If this is the case, try to locate the sound and tighten the screw.

Rattling can also indicate a cracked heat exchanger, which can be detrimental to your health. The presence of carbon monoxide is often lethal. If tightening a screw didn’t stop the rattling, schedule an appointment with WM Henderson right away.

Squealing or Screeching Noises

Screeching or squealing sounds may not get your attention right away, but if you do notice them it’s best to contact an HVAC technician to fix them. If your furnace is creating screeching noises when it’s running, this is a sign of various types of issues such as a faulty blower motor, broken blower belt, or dry shaft bearings. A qualified technician will thoroughly evaluate your system and perform the correct repairs to restore optimal performance.

Furnace Repair & Installation Services

Has it been a while since your furnace was serviced? Is your furnace producing a buzzing noise when it’s running? If you answered yes, contact the technicians at WM Henderson for furnace repair and furnace installation services. Furnace buzzing noises when running are annoying, but they can be fixed. Prolong the lifespan of your heating system and its parts with regular maintenance. In addition, our team of technicians offers other types of HVAC repair services including boiler installation, heat pump replacement, and furnace tune-up. Our HVAC professionals service locations such as Ardmore, West Chester, Wayne, Drexel Hill, Havertown, and Broomall. Discover why we’re the top choice for HVAC services in Pennsylvania. Book an appointment online or give us a call at (484) 206-8594.

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