Why Is My Furnace Making a Buzzing Noise?

Have you heard a buzzing sound when your furnace turns on for a heating cycle? In our most recent blog, the heating and cooling technicians at Hans Heating & Air explain the causes of a furnace buzzing noise and what you should do about it. For heating system help in your Montgomery, AL, area home, call Hans Heating & Air.

Reasons Why a Furnace Buzzes

If your furnace is making a loud buzzing or humming sound when starting a heating cycle, here are a few reasons commonly to blame for these unusual sounds:

  • A loose transformer box. The furnace is equipped with a transformer that converts incoming voltage to the voltage required by the system. If the mount of the transformer comes loose, 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.
  • Bad capacitor. The furnace’s capacitor stores electricity to help its motor start up when a heating cycle is called for by the thermostat. When this component goes bad, a buzzing sound may result.
  • Blower motor malfunction. The blower motor runs to circulate warm air through the ducts and into your home. When the motor is going bad or has failed, you may hear a buzzing sound that occurs when the furnace powers up.
  • Loose ductwork. If the loud buzzing sound seems to come from the duct system and not the furnace, loose connections may be to blame. As air is forced through the HVAC system, the pressure can cause loose sections of sheet metal to vibrate against each other.

A furnace buzzing noise likely requires a professional to fix, as components need to be replaced. If the transformer box has simply become loose and the transformer itself has not gone bad, it may be possible to tighten it up on your own to resolve the buzzing sound. Use a screwdriver to tighten the screws and secure the box to the furnace. If this does not correct the noise, call your heating and air conditioning technician to replace the transformer.

It may be possible to re-secure loose ducts on your own. If you are able to access the ducts, inspect connections for gaps and loose-fitting joints. Mastic sealant and foil tape may be used to seal loose connections. Do not use duct tape. Despite the name, it is not meant for your ducts!

If you are unable to access your ductwork or cannot locate the source of the buzzing sound, call your HVAC technician to inspect the ducts and repair them. You don’t want to ignore this issue, as over time the connection may become fully loose and a section of ductwork could fall. This causes significant energy waste, and you’ll notice it’s hard to maintain comfortable temperatures in the affected area of your home.

Furnace Repair from Hans Heating & Air

When your furnace makes a buzzing noise when it starts up, don’t ignore this warning sign – furnace noises that aren’t typical are indicators of a problem somewhere in the system. Call Hans Heating & Air for reliable furnace repairs in your Montgomery, AL, area home. Our technicians fully inspect your system to pinpoint the issue to blame when your furnace makes a buzzing noise. They then make durable repairs to stop the noise and prevent further problems. For all of your home’s HVAC repair and installation needs, contact Hans today.

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