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February 16, 2023

Bang, knock, clang, rattle, click, whistle, buzz, and hum. Has your heater been talking to you? If your furnace sounds like it is playing in a band on Friday night, something is not right. Our Marin, Sonoma, and Napa County nights still get pretty chilly during this time of the year, so now is not the time to ignore issues with your furnace or leave them unresolved. If your heating system is making noises, it is trying to tell you something, so you should listen. If you have to ask yourself, “What’s that noise coming from my heater?”, you likely have an issue.

What’s That Noise Coming From my Heater?

While your heating system may be working as intended, if it has started to make new sounds and loud noises, that is usually an indication that something is about to go wrong. Typically, when your furnace starts to make new sounds, it is a sign that something is not right. While some furnace noises may be normal, if they are new and persistent, they should not be ignored. Below we review some common sounds you may be hearing and what they could possibly mean.

- Banging or Knocking: When you hear a banging or knocking noise when your heater is running, it usually means that parts are going bad or you have dirty furnace burners. There are various parts and pieces of your furnace that can go bad and cause it to produce a knocking noise as it functions. Dirty furnace burners can cause your furnace not to ignite properly and can produce a buildup that will create the banging noise. This is basically a mini-explosion in the furnace, as the furnace is not able to function as it should.

- Rattling: If you hear a rattling while your heater is on, it could be a sign that your ductwork is loose. Rattling, vibrating, knocking/banging, or whistling sounds usually mean that your ductwork has something loose, a hole, and disconnected joints, amongst other things. The rattling could also be coming from loose panels that need to be tightened. Professional duct cleaning could help you identify any of these issues, before they cause noticeable issues for your HVAC system.

- Clicking: If you have to ask, “What’s that noise coming from my heater?” and it’s what seems like a constant clicking sound, the most common causes are an ignition system malfunction or internal part damage. A repeated clicking indicates a system malfunction, due to your furnace’s spark igniter trying to light the pilot light or burners.

- Whistling: Usually the main cause of a furnace that whistles while it works is a dirty air filter that is restricting airflow. Airflow problems within your heater cause a constant whistling noise. This can also be caused from a leak or gap somewhere in the system allowing air to escape or could indicate a problem with the unit’s blower or motor.

- Buzzing or Humming: While all heating systems generate some light noise, they should run quiet enough not to be disruptive the majority of the time. If you notice a loud buzzing or humming, it can indicate various mechanical or electrical problems, either when the furnace starts up or throughout its operation. If the sound is loudest during startup, the main culprit could be an issue with your blower fan motor. If it’s a blower fan issue, the noisiness may or may not improve after startup.

As we said, if your North Bay Area heater sounds like it is playing in a band, and likely not a good one, and you have ask, “What’s that noise coming from my heater?”, you probably have a problem and should call in a Marin, Sonoma, and Napa County heating professional.

Regardless of whether it is a repair or replacement, you can depend on Bragg for expert consultation that meets or exceeds your expectations. We will always give you an honest assessment of your heating situation so you can make an informed decision.

Bragg Cooling, Heating & Plumbing is a full service HVAC company that is licensed to solve all your furnace related problems, including repair, replacement, maintenance and safety inspection. We’ve been repairing and installing furnaces since 1968. Contact us today.


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