What’s That Smell Coming from Your Furnace? We’ll Explain


Did you know that humans can detect over one trillion different smells? Of all our senses, smell is also our most memorable one, which is why we can still recognize scents from our childhood. Want another impressive fact about your nose? It can often detect an issue with your furnace. So if you get a whiff of a strange odor coming from your heating system, it’s a good idea to investigate. 

What’s That Smell Coming from Your Furnace?

Many furnace issues can produce an odor, and depending on the type of smell, you can often narrow down what may be causing it. Diagnosing the source can help decide whether it’s safe to continue running the furnace or if you should take any safety precautions.  

Common smells that indicate a problem with your furnace

  • Burning plastic – The smell of burning plastic coming from your furnace could be one of a few issues, including a faulty capacitor, broken fan belt, or electrical fault involving plastic-coated wires. If the odor persists or gets worse, get it looked at right away, or you could have a fire hazard in your home.
  • Metal or electric burning – This odor is often caused by an overheating blower motor. After turning the unit off to cool down, replace the air filter. If that doesn’t work, have your furnace inspected.
  • Burning dust – After sitting dormant for a few months, it’s common for the furnace to smell a little dusty when it turns on. However, this odor should go away pretty quickly. If it doesn’t, a few things you can try include replacing the air filter or having your ducts professionally cleaned.
  • Gunpowder – If you smell what is commonly described as a gunpowder smell, the most likely explanations are a faulty fan motor or circuit board. Both of these are serious issues, so we recommend turning the unit off and calling an HVAC professional.
  • Rotten eggs – If you have a natural gas furnace, do not ignore the stench of rotten eggs, which could mean you have a gas leak in your home. Turn off the furnace, remove yourself (and all other people and pets) from the home, and call your natural gas provider.
  • Smoke or oil – If you have an oil furnace, you shouldn’t smell the oil or a smoky odor inside your home. 

Furnace maintenance and repair in Los Banos, Turlock, Merced, and Patterson

If your nose senses something is afoul with your furnace, don’t ignore this very important warning sign. Contact the Central Valley heating experts at All American Plumbing, Heating & Air. To schedule maintenance or repair service, call us today at (209) 710-5629.