If your furnace smells while heating, it’s trying to tell you something’s up. We’ve put together a list of the top six furnace smells so you can learn what causes them and how to repair them. These include:

  1. Burning smell from furnace
  2. Furnace smells like burning plastic
  3. Gas smell from furnace
  4. Furnace smells like sewer
  5. Furnace smells musty

1. The Furnace Smells Like It’s Burning

Cause: Dusty Furnace

If your furnace smells like burning, it’s probably occurring when you turn on your furnace for the first time in the fall. Like anything else in your home, your furnace accumulates dust over time. This dust burns off when you turn on the heat, causing the burning dust smell from your furnace.

2. The Furnace Smells Like Plastic Is Burning

Cause: Electrical Problem

If your furnace smells like burning plastic or burning rubber, it might have an electrical issue. This smell of burning can be caused by melting plastic wire casing, which is a safety issue. If you’re noticing a melted plastic smell, turn off your heating system right away and call us at 715-384-3163 for furnace repair.

Cause: Overheated Motor or Cracked Furnace Exchanger

An electrical burning smell could also mean your furnace motor is overheated or the heat exchanger is cracked. The heat exchanger safely exhausts carbon monoxide that’s naturally produced during the combustion process.

If it cracks, carbon monoxide can seep into your house. This invisible gas is fatal in large doses. So, it’s important to have an HVAC professional do routine furnace maintenance and have functional carbon monoxide detectors.

Other symptoms of a cracked heat exchanger include:

  • Soot on or inside the furnace
  • Yellow burner flame, instead of blue
  • Chemical smell from furnace, such as formaldehyde
  • Water near your furnace, as long as the condensate drain isn’t blocked
  • Flu-like symptoms

3. The Furnace Smells Like Gas or Rotten Eggs

It’s normal for your heating system to give off a small amount of gas when it turns on, so you might notice a gas smell from your furnace. But it’s not normal to be smelling natural gas or rotten eggs throughout your home on a daily basis.

Cause: Gas Leak

If your furnace smells like gas continuously, shut it down. If you know where your main gas supply valve is, turn that off too. Then call the gas company and us for help.

4. Furnace Smells Like Sewer

If your furnace smells like sewer, or rotten eggs, you’ll want to make sure you don’t have a gas leak. If you don’t, the issue could be with your sewer lines and not your furnace. This is especially true if it’s been extremely dry lately.

Cause: Dry Sewer Trap or Sewer Leak

If you suspect your sewer trap is dry, you can try putting some water down the floor drain in your basement. If that doesn’t fix the issue, you might have a sewer leak, so you’ll want to call a company that handles sewer line repair.

5. The Furnace Smells Like Mold

If your furnace smells musty, mold and mildew have likely been growing in it for a while.

Cause: Dirty Ductwork

Your furnace works with air ducts to distribute warm air throughout your home. Mold can grow in the ductwork over time, especially if you live in a humid climate. You can get rid of the mold by having an HVAC technician do air duct cleaning.

Depend on Us for Your Furnace Repair Needs

Trying to fix your heating and cooling system by yourself is difficult. Your comfort is our top priority at House of Heating Incorporated, so our professionals are here to help you when you need us. When you need furnace repair in Marshfield that you can depend on, contact us at 715-384-3163.