ASK PHIL: Why does my furnace smell when I turn it on?

Some people turn on their heat during the first chilly day of fall. Other people hold off until their family members are so cold they threaten to revolt. No matter when you opt to turn on your furnace for the first time this season, you may smell something a little strange.

Chances are it is normal dust burn-off and is nothing to be concerned about. During the warmer months, when your furnace was not being used, it is typical for dust to settle and accumulate. This burns off when you initially turn it on in the fall or winter. The smell should dissipate but if it doesn’t it is important to have it checked.

There are other odors caused by various sources that are important to keep in mind.

Electrical Burning Smell

If an electrical or metallic odor is coming from your furnace you could have a wiring issue or overheated motor. You want to get this checked and fixed promptly by an HVAC specialist to avoid a potential electrical fire.

Melted or Burning Plastic Smell

You would be surprised at what has found its way into heating units. If you smell something like burning plastic it could be a plastic toy or other foreign object. If you don’t see the object it is important to call a professional.

Smell of Gunpowder

If the circuit board or fan motor in your furnace overheats it could emit a gunpowder like odor. If you smell this, turn your furnace off and contact a HVAC professional.

Moldy or Musty Smell

If your home is smelling more like a locker room, it may be time to change your filter. If that doesn’t solve the issue you could have mold buildup in your ductwork or cooling coil. These require cleaning by an HVAC professional. This is important to maintain good Indoor Air Quality throughout your home.

Smells Like Sulfur or Rotten Eggs

If you have gas appliances and smell gas (sulfur or rotten eggs), it is imperative you and anyone else in your home (including pets) leave and call the gas company immediately.