Bad Furnace Sounds and Smells – Dial One Sonshine

Now that we’re in the heart of winter, it’s safe to say you’ve turned on your furnace–but is it making some noises or odors you don’t remember it producing last year? While some sounds and smells are normal for furnaces to make, others can be warning signs of a severe malfunction with your heating equipment.

If you encounter any of these noises or smells coming from your furnace, it’s time to call a technician.

Bad Furnace Sounds

Banging or Popping

Occasionally, you might hear a small bang or pop as your HVAC system’s air ducts expand and contract. However, if these noises are particularly loud, contact a technician to examine your furnace for a combustion issue.


This sound is somewhat difficult to describe. Some people say that they can hear a sort of “clunking” noise when their furnace is on. You will most often hear this sound when there’s an issue with the belt.


The common culprit behind a screeching furnace is either a bad belt or a bad motor bearing. A technician will need to replace the belt if it’s broken or worn out. If a bearing is the issue, the technician can usually apply a specific lubricant to solve the problem.

Scraping or Scratching

If you hear what sounds like metal scraping together, there is likely an issue with your furnace’s blower wheel. In most cases, a technician only needs to repair the wheel by tightening it, but if you delay this repair, this blower wheel problem can ultimately damage your heating system.

Bad Furnace Smells

A Musty Odor

A musty smell indicates mold growth. With the right amount of warmth and moisture, mold can grow on just about any surface in your home, and your furnace is no exception. In some cases, the mold may come from your air filters, air ducts, or the drip pan. A professional cleaning service may be needed if the mold problem is severe enough.

A Burning Smell

If something smells like it’s burning, there could be something caught in the ducts. If there was a spill or the motor is overheated, then that could also produce this smell. You’ll need to contact a professional to inspect your furnace to find the cause.

For professional heating repair and maintenance in Orange County and the surrounding areas, call Dial One Sonshine at (714) 613-1016 today.

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