It’s common to smell uncharacteristic smells from your furnace from time to time, but it can be tricky to decipher whether or not the smell requires your attention. While furnaces may sometimes smell off when they’re first used for the year, other smells may indicate a real problem.

Here are five of the most common smells your furnace may be giving off:

  • Burning dust
  • Metallic or Plastic-y
  • Rotten Eggs
  • Mildew and Must
  • Feet

Let’s explore each of these smells in more detail below. By the time you’re done with this article, you should be able to diagnose common issues with your furnace.

Burning Dust

The smell of burning dust is that “first of the year” smell you experience when you use your furnace for the first time in the season. In most cases, this smell isn’t cause for concern and will go away with more use. If you’re worried, you may be able to combat the smell by changing out your filters before running your furnace. This way, the filter will be more likely to catch residual dust when the heat turns on.

Smelling Metal or Plastic

If you smell the aroma of burning metal or plastic, it likely means something is overheating. If this is the case, turn off your heat before investigating to ensure your safety. If you find an issue, it’s best to call in a professional to avoid messing up any type of warranty you have on your home or heating system.

Rotten Eggs

The smell of rotten eggs is never a good sign. Usually, this means there’s a gas leak inside of your tank. This is an extremely dangerous situation, so it’s essential you turn your heat off and call in a professional right away. Natural gas, on its own, is completely odorless. Because of that, there are additives put into gas lines to make the smell unpleasant and signal anyone inside to evacuate as soon as possible.

A Musty or Mildew Smell

If you smell a damp or moldy smell, it likely means damage in your furnace has caused moisture buildup. This buildup has then caused mold and mildew to grow inside, and sometimes outside, of your furnace. This is another situation that constitutes the help of a professional.

Smelling Feet

When you smell feet or another unpleasant smell that resembles body odor coming from your furnace, it’s likely due to bacteria buildup. If this is the case, you’re going to need to shut off your heat and call a professional to assess and repair your furnace.

Parting Thoughts

When you smell something coming from your furnace and air ducts, it can be concerning. To ease your anxiety, it’s helpful to remember that burning dust is rarely a cause to be concerned about. On the other hand, being able to indicate your furnace smells like rotten eggs could, quite literally, be the difference between life and death for you and those who live with you.

It’s important to know when to call in a professional and we hope this article has helped you make that decision.

Meet the Author
Chastain Mills
Chastain Mills

General Manager

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