Why Your Furnace Has a Strange Smell

As the weather cools down and you swap from cooling to heating your home, you may be worried about weird furnace smells filling the air. Find out what the most common furnace smells could mean and how worried you should be about each one. 

The Furnace Smells Musty 

Musty furnace odors usually indicate mold growth somewhere in the HVAC system. To avoid exposing your family to allergy-inducing mold, tackle this problem as soon as possible. 

A wet air filter can encourage mold, so getting rid of the smell can be as simple as replacing the filter. If that fails to remove the smell, the AC evaporator coil fastened near the furnace might be the culprit. This component accumulates condensation, which could induce mold growth. You’ll be better off with a professional’s help to examine and clean the evaporator coil. When the problem still won’t go away, consider scheduling air duct cleaning. This service eliminates hidden mold, regardless of where it’s growing in your ventilation. 

The Furnace Smells Like Rotten Eggs 

This is one of the most concerning furnace smells because it most likely indicates a gas leak. The utility company includes a special substance called mercaptan to the natural gas supply to make leaks easier to detect. 

If you recognize a rotten egg smell close to your furnace or originating from your ductwork, switch off the heater right away. If you remember where the main gas supply valve is placed, shut that off as well. Then, leave the house and dial 911, as well as your gas company. Don’t go back in the house until a professional can verify it’s safe. 

The Furnace Has a Sour Stench 

If you discover a sour smell that stings your nose while close to64} the furnace, this may mean the heat exchanger cracked open. This essential component safely contains68} combustion fumes, like carbon monoxide, so a crack might pump unsafe levels of CO gas into your home. 

Carbon monoxide poisoning has the potential to be deadly, so shut off your furnace as soon as possible if you detect a sour odor. Then, reach out to an HVAC professional for an inspection. Consider replacing your furnace if a cracked heat exchanger is to blame. For your health and safety going forward, ensure you have working CO detectors on all floors of your home. 

The Furnace Smells Dusty 

When you turn on the furnace for the first time every fall, you can expect a dusty odor to appear for a little while. This is the smell of six months’ worth of dust burning off as the furnace wakes from its summer slumber. As long as the smell goes away within a day, you shouldn’t have anything to worry about. 

The Furnace Has a Smoky Smell 

Natural gas, oil and propane furnaces are combustion appliances, so they vent fumes up and out of your home. A smoky smell could mean the flue is backed up, and now fumes are flowing back into your home. The odor can reach through the entire house, jeopardizing your family’s health if you ignore it. So turn off the furnace and contact a professional as soon as you can to request furnace repair. 

The Furnace Smells Like It’s Burning Plastic 

Overheating and melted electrical components are the most plausible reason for a burning plastic smell to appear. A malfunctioning fan motor is also possible. If you don’t tackle the problem, an electrical fire might start, or your furnace could experience irreparable damage. Disable the heating system immediately and contact an HVAC technician for help identifying and repairing this unpleasant furnace smell. 

The Furnace Has an Oily Smell 

If you use an oil furnace, you may detect this smell when the oil filter becomes blocked up. Try replacing it to see if that resolves the problem. If the smell lingers for more than 24 hours after taking care of this step, it could indicate an oil leak. You should get help from an HVAC expert to address this problem. 

The Furnace Reeks of Sewer Odors 

Sewer gas smells pretty similar to spoiled eggs, so first eliminate the possibility of a natural gas leak. If that’s not the issue, the sewer lines might have an issue, such as a dry trap or sewer leak. Try pouring water down your own drains, including the basement floor drain, to replenish dried-up sewer traps. If the smell sticks around, you’ll need to contact a sewer line repair company. 

Contact Service Experts Heating, Air Conditioning & Plumbing for Furnace Repair 

If you’re still uncertain, get in touch with an HVAC technician to check and repair your furnace. At Service Experts Heating, Air Conditioning & Plumbing, we offer thorough diagnostic services to identify the problem before repairs begin. Then, we encourage the most viable, cost-effective repairs, alongside an up-front estimate for every option. Our ACE-certified technicians can manage just about any heating problem, and we back our work with a 100% satisfaction guarantee for one year. For details about why your furnace smells bad or to request furnace repair near you, please contact your local Service Experts Heating, Air Conditioning & Plumbing office today. 

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