Why Your Furnace Has a Strange Smell

As the weather turns cold and you switch from cooling to heating your home, some homeowners are worried about unusual furnace smells filling the air. Learn what the most common furnace smells could mean and how concerned you should be about them. 

The Furnace Smells Musty 

Musty furnace odors usually imply mold growth someplace in the HVAC system. To avoid subjecting your family to these microorganisms, address this problem as soon as possible. 

A damp air filter can harbor mold, so getting rid of the smell can be as straightforward as replacing the filter. If that doesn’t help, the AC evaporator coil mounted near the furnace might be the culprit. This component collects condensation, which can trigger mold growth. You’ll be better off with a professional’s help to inspect and clean the evaporator coil. When all else fails, consider requesting air duct cleaning. This service eliminates hidden mold, no matter where it’s growing in your ventilation. 

The Furnace Smells Like Spoiled Eggs 

This is one of the most concerning furnace smells due to the fact that it probably implies a gas leak. The utility company puts in a useful substance called mercaptan to the natural gas supply to make leaks more easily detected. 

If you detect a rotten egg smell around your furnace or coming from your ductwork, shut off the heater straightaway. If you know where the main gas supply valve is located, shut that off also. Then, leave the house and call 911, as well as your gas company. Don’t go back in the house until a professional tells you 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 could mean the heat exchanger is cracked. This vital component contains68} combustion fumes, including carbon monoxide, so cracks might allow unsafe levels of CO gas into your home. 

Carbon monoxide poisoning can be deadly, so shut off your furnace immediately if you recognize a sour odor. Then, call an HVAC professional for an inspection. Consider replacing your furnace if a cracked heat exchanger is to blame. For your family’s safety going forward, see to it that you have reliable CO detectors on all floors 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 fill the house for a few minutes. This is the smell of six months’ worth of dust burning up as the furnace wakes up. As long as the smell goes away 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 up and out of your home. A smoky smell can mean the flue is clogged, and now fumes are backdrafting into your home. The odor might eventually reach the entire house, risking your family’s health if you neglect it. So shut down 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 burned electrical components are the most plausible reason for a burning plastic smell to come from your furnace. A malfunctioning 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. Disable the heating system immediately and contact an HVAC technician for help diagnosing and repairing this weird furnace smell. 

The Furnace Has an Oily Smell 

If you use an oil furnace, you could notice this stench if the oil filter becomes blocked up. Try replacing it to see if that addresses the problem. If the smell persists for more than 24 hours after taking care of this step, it could indicate an oil leak. You should get help from an HVAC professional to handle this problem. 

The Furnace Reeks of Sewer Odors 

Sewer gas smells quite similar to rotting eggs, so first eliminate the possibility of a natural gas leak. If that’s not the source, the sewer lines might have an issue, for example a dry trap or sewer leak. Try pouring water down your own drains, including the basement floor drain, to refresh dry sewer traps. If the smell persists, you should 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 assess and repair your furnace. At Service Experts Heating, Air Conditioning & Plumbing, we offer thorough diagnostic services to pinpoint the problem before the work begins. Then, we suggest the most viable, cost-effective repairs, alongside an up-front estimate for each option. Our ACE-certified technicians can handle just about any heating problem, 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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