Why Your Furnace Has a Strange Smell

As the weather gets colder and you switch from cooling to heating your home, you may be worried about strange furnace smells filling the air. Learn what the most common furnace smells mean and how proactive you should be about each one. 

The Furnace Smells Musty 

Musty furnace odors almost always imply mold growth hiding in the HVAC system. To avoid exposing your family to these microorganisms, handle this problem right away. 

A wet air filter can harbor mold, so getting rid of the smell can be as easy as swapping out filter. If that doesn’t work, the AC evaporator coil mounted near the furnace might be the culprit. This component collects condensation, which can stimulate mold growth. You’ll need a professional’s help to check and clean the evaporator coil. When this still doesn’t help, take a look at scheduling air duct cleaning. This service eliminates hidden mold, no matter where it’s growing in your ductwork. 

The Furnace Smells Like Spoiled Eggs 

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

If you detect a rotten egg smell around your furnace or out of your vents, shut off the heater right away. If you know where the main gas supply valve is, shut that off too. Then, leave the house and call 911, in addition to your gas company. Don’t go back in the house until a professional confirms it’s safe. 

The Furnace Has a Sour Stench 

If you notice a sour smell that stings your nose while standing near64} the furnace, this might mean the heat exchanger is cracked. This vital component safely contains68} combustion fumes, like carbon monoxide, so a cracked heat exchanger might allow unsafe levels of CO gas into your home. 

Carbon monoxide poisoning has the potential to be deadly, so switch off your furnace right away 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, make sure you have functional CO detectors on each floor of your home. 

The Furnace Smells Dusty 

When you start the furnace for the first time every fall, you probably expect a dusty odor to appear for a brief moment. This is the smell of six months’ worth of dust burning up as the furnace wakes from its summer slumber. As long as the smell disperses within one day, you don’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 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, jeopardizing your family’s health if you neglect it. So shut down the furnace and get in touch with a professional as soon as you can to arrange for repair. 

The Furnace Smells Like Burning Plastic 

Overheating and burned electrical components are the most plausible reason for a burning plastic smell to make an appearance. A faulty fan motor is also possible. If you don’t tackle the problem, an electrical fire might start, or your furnace could end up with irreparable damage. Shut off the heating system as soon as possible and contact an HVAC technician for help identifying and repairing this unusual furnace smell. 

The Furnace Has an Oily Smell 

If you have an oil furnace, you may notice this smell whenever the oil filter becomes blocked up. Try replacing it to find out if that resolves the problem. If the smell remains for more than 24 hours after taking care of this step, it might 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 determine the possibility of a natural gas leak. If that’s not the source, your sewer lines might have an issue, like a dry trap or sewer leak. Flush water down all your drains, including the basement floor drain, to fill dry sewer traps. If the smell lingers, go ahead and contact a sewer line repair company. 

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

If you’re still unsure, call an HVAC technician to examine and repair your furnace. At Service Experts Heating, Air Conditioning & Plumbing, we offer comprehensive diagnostic services to pinpoint the problem before we figure out the best solution. Then, we recommend the most viable, cost-effective repairs, alongside an up-front estimate for all options. Our ACE-certified technicians can resolve just about any heating malfunction, 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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