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Why Your Furnace Has a Strange Smell

As the weather turns cold and you switch from cooling to heating your home, you may be worried about weird furnace smells floating in the air. Find out what the most common furnace smells mean and how worried you should be about each one. 

The Furnace Smells Musty 

Musty furnace smells usually indicate mold growth somewhere in the HVAC system. To avoid exposing your family to mold and mildew spores, tackle this problem as quickly as possible. 

A clogged air filter can encourage mold, so wiping out the smell might be as straightforward as replacing the filter. If that fails to remove the smell, the AC evaporator coil mounted near the furnace may be to blame. This component collects condensation, which will sometimes 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, take a look at investing in air duct cleaning. This service eliminates hidden mold, regardless of where it’s hiding in your ductwork. 

The Furnace Smells Like Rotten Eggs 

This is one of the most nerve-wracking furnace smells since it most likely indicates a gas leak. The utility company includes a particular substance known as mercaptan to the natural gas supply to make leaks easier to detect. 

If you recognize a rotten egg smell around your furnace or out of your ductwork, switch off the heater right away. If you remember where the main gas supply valve is placed, shut that off too. Then, leave the house and dial 911, in addition to your gas company. Don’t enter the house until a professional confirms it’s safe. 

The Furnace Has a Sour Stench 

If you discover a sour smell that stings your nose while standing near64} the furnace, this might mean the heat exchanger is cracked. This important component contains68} combustion fumes, including carbon monoxide, so cracks might pump unsafe levels of CO gas into your home. 

Carbon monoxide poisoning can be fatal, so turn off your furnace right away if you recognize a sour odor. Then, reach out to an HVAC professional for an inspection. Consider replacing your furnace if a cracked heat exchanger is the culprit. For your continued safety going forward, ensure you have reliable CO detectors on every floor of your home. 

The Furnace Smells Dusty 

When you fire up the furnace for the first time after a while, you probably expect a dusty odor to fill the house for a brief moment. This is the smell of six months’ worth of dust burning off as the furnace wakes up. As long as the smell dissipates within 24 hours, 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 safely out of your home. A smoky smell will sometimes mean the flue is backed up, and now fumes are backdrafting into your home. The odor may permeate the entire house, risking your family’s health if you let it continue. So shut down the furnace and get in touch with a professional straightaway to schedule a repair. 

The Furnace Smells Like Burning Plastic 

Overheating and melted electrical components are the most common reason for a burning plastic smell to appear. A failing fan motor is another common cause. If you don’t correct the problem, an electrical fire might start, or your furnace could suffer from irreparable damage. Shut off the heating system as soon as possible and call an HVAC technician for help troubleshooting and repairing this weird furnace smell. 

The Furnace Has an Oily Smell 

If you own an oil furnace, you could notice this smell whenever the oil filter becomes blocked up. Try replacing it to see if that fixes the problem. If the smell lingers for more than one day after completing this step, it might suggest an oil leak. You should get help from an HVAC specialist to fix this problem. 

The Furnace Smell Resembles 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 could have an issue, like a dry trap or sewer leak. Pour water down the drains, including the basement floor drain, to replenish dried-out sewer traps. If the smell sticks around, go ahead and contact a sewer line repair company. 

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

If you’re still uncertain, contact an HVAC technician to examine and repair your furnace. At Service Experts Heating, Air Conditioning & Plumbing, we perform comprehensive diagnostic services to determine the problem before repairs begin. Then, we suggest the most viable, cost-effective repairs, along with an up-front estimate for each option. Our ACE-certified technicians can resolve just about any heating repair, 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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