If your furnace smells while heating, it’s trying to tell you something’s up. 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:
- Burning smell from furnace
- Furnace smells like burning plastic
- Gas smell from furnace
- Furnace smells like sewer
- 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 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 520-415-5681 for furnace repair.
Cause: Overheated Motor or Cracked Furnace Exchanger
An electrical burning smell could also mean your furnace motor is too hot or the heat exchanger is cracked. The heat exchanger safely gets rid of carbon monoxide that’s naturally produced during the combustion process.
If it cracks, carbon monoxide can seep into your house. This colorless gas is fatal in heavy concentrations. So, it’s important to have an HVAC professional do routine furnace maintenance and have working carbon monoxide detectors.
Other signs 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 around your furnace, as long as the condensate drain isn’t blocked
- Flu-like symptoms
3. Gas Smell from Furnace
It’s normal for your heating system to let off a small amount of gas when it starts up, so you might get 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 call the gas company and us for assistance.
4. Furnace Smells Like Sewer
If your furnace smells like sewer, or rotten eggs, you’ll want to ensure 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 think 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 contact 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 some time.
Cause: Dirty Ductwork
Your furnace uses air ducts to send warm air throughout your house. Mold can grow in the ductwork as time goes on, particularly 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
Troubleshooting your heating and cooling system on your own is hard. Your comfort is our top priority at Arizona Comfort Systems, so our pros are here to help you when you need us. When you need furnace repair in Sierra Vista that you can depend on, call us at 520-415-5681.