If your furnace smells while heating, it’s trying to tell you something’s wrong. We’ve compiled a list of the top six furnace smells so you can know 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. Burning Smell from Furnace

Cause: Dusty Furnace

If your furnace smells like burning, it’s probably happening 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 up 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 problem. 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 630-313-2509 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 created during the combustion process.

If it cracks, carbon monoxide can seep into your home. This invisible gas is fatal in heavy concentrations. So, it’s important to have an HVAC professional do annual 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, like formaldehyde
  • Water around your furnace, as long as the condensate drain isn’t plugged
  • Flu-like symptoms

3. The Furnace Smells Like Gas or Rotten Eggs

It’s normal for your heating system to let off a little bit of gas when it turns on, so you might notice a gas smell from your furnace. But it’s not typical 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, turn it off. If you know where your main gas supply valve is, shut that off too. Then contact the gas company and us for help.

4. The Furnace Smells Like Sewage

If your furnace smells like sewer, or rotten eggs, you’ll want to make sure you aren’t dealing with 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 pouring some water down the floor drain in your basement. If that doesn’t fix the problem, you might have a sewer leak, so you’ll want to call a company that handles sewer line repair.

5. Furnace Smells Musty

If your furnace smells musty, mold and mildew have probably been growing in it for some time.

Cause: Dirty Ductwork

Your furnace uses 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 eliminate the mold by having an HVAC technician do air duct cleaning.

You Can Count on Us for Your Furnace Repair Needs

Trying to fix your heating and cooling system by yourself is difficult. Your comfort is our number one goal at Pure Comfort Heating and Air Conditioning, so our pros are here to help you when you need us. When you need furnace repair in Streamwood that you can depend on, call us at 630-313-2509.