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 unusual furnace smells floating in the air. Find out what the most common furnace smells could mean and how concerned you should be about them. 

The Furnace Smells Musty 

Musty furnace odors usually indicate mold growth hiding in the HVAC system. To avoid exposing your family to these microorganisms, tackle this problem as quickly as possible. 

A wet air filter can harbor mold, so getting rid of the smell could be as straightforward as swapping out filter. If that fails to remove the smell, the AC evaporator coil placed near the furnace could be the culprit. This component accumulates condensation, which can stimulate mold growth. You’ll want a professional’s help to check and clean the evaporator coil. When all else fails, take a look at scheduling air duct cleaning. This service cleans away hidden mold, regardless of where it’s hiding in your air ducts. 

The Furnace Smells Like Spoiled Eggs 

This is one of the most concerning furnace smells due to the fact that it frequently suggests a gas leak. The utility company includes a particular substance known as mercaptan to the natural gas supply to make leaks easier to notice. 

If you notice a rotten egg smell around your furnace or coming from your vents, shut down the heater straightaway. If you know where the main gas supply valve is, shut that off also. Then, leave the house and call 911, followed by your gas company. Don’t enter 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 standing near64} the furnace, this might mean the heat exchanger cracked open. This important component contains68} combustion fumes, such as carbon monoxide, so a crack might spew unsafe levels of CO gas into your home. 

Carbon monoxide poisoning could be deadly, so shut off your furnace immediately if you recognize a sour odor. Then, contact an HVAC professional for an inspection. Consider replacing your furnace if a cracked heat exchanger is responsible. For your health and safety going forward, make sure you have working CO detectors on every floor of your home. 

The Furnace Smells Dusty 

When you fire up the furnace for the first time each fall, you probably expect a dusty odor to show up for a brief moment. This is the smell of six months’ worth of dust burning away as the furnace wakes up. As long as the smell disperses within a day, you have nothing to worry about. 

The Furnace Has a Smoky Smell 

Natural gas, oil and propane furnaces are combustion appliances, so they vent fumes to the exterior. A smoky smell can mean the flue is blocked, and now fumes are flowing back into your home. The odor might eventually reach the entire house, risking your family’s health if you let it continue. So turn off the furnace and contact a professional right away to request furnace repair. 

The Furnace Smell Resembles Burning Plastic 

Overheating and melting electrical components are the most plausible reason for a burning plastic smell to appear. A malfunctioning fan motor is another common cause. If you don’t tackle the problem, an electrical fire may start, or your furnace could suffer from irreparable damage. Disable the heating system as soon as possible and contact an HVAC technician for help identifying and repairing this unpleasant furnace smell. 

The Furnace Has an Oily Smell 

If you own an oil furnace, you could detect this odor when the oil filter becomes clogged. Try replacing it to find out if that resolves the problem. If the smell lingers for more than one day after carrying out this step, it may suggest an oil leak. You should get help from an HVAC professional to fix this problem. 

The Furnace Smells Like Sewer Odors 

Sewer gas smells very similar to spoiled eggs, so first determine the likelihood of a natural gas leak. If that’s not the source, your home’s sewer lines may have an issue, like a dry trap or sewer leak. Flush water down your own drains, including the basement floor drain, to refresh dried-out sewer traps. If the smell lingers, you should contact a sewer line repair company. 

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

When in doubt, call an HVAC technician to examine and repair your furnace. At Service Experts Heating, Air Conditioning & Plumbing, we perform comprehensive diagnostic services to identify the problem before repairs begin. Then, we suggest the most viable, cost-effective repairs, as well as an up-front estimate for all options. Our ACE-certified technicians can manage just about any heating repair, and we back our work with a 100% satisfaction guarantee for one year. To learn more 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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