Why Your Furnace Has a Strange Smell

As the weather cools down and you switch from cooling to heating your home, you might be worried about weird furnace smells floating in the air. Learn what the most common furnace smells mean and how concerned you should be about each one. 

The Furnace Smells Musty 

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

A wet air filter can harbor mold, so getting rid of the smell might be as easy as replacing the filter. If that doesn’t work, the AC evaporator coil mounted near the furnace could be the root of the problem. This component collects condensation, which could induce mold growth. You’ll want a professional’s help to check and clean the evaporator coil. When all else fails, consider scheduling air duct cleaning. This service cleans away hidden mold, no matter where it’s growing in your ductwork. 

The Furnace Smells Like Rotten Eggs 

This is one of the most nerve-wracking furnace smells because it most likely suggests a gas leak. The utility company adds a useful substance known as mercaptan to the natural gas supply to make leaks more easily detected. 

If you recognize a rotten egg smell near your furnace or coming from your vents, shut off the heater straightaway. If you know where the main gas supply valve is, shut that off too. Then, evacuate your home and call 911, followed by 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 detect a sour smell that stings your nose while standing near64} the furnace, this could mean the heat exchanger cracked open. This vital component contains68} combustion fumes, including carbon monoxide, so cracks could pump unsafe levels of CO gas into your home. 

Carbon monoxide poisoning can be fatal, so shut off your furnace right away if you recognize a sour odor. Then, contact 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, 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 can 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 from its summer slumber. As long as the smell dissipates 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 could mean the flue is clogged, and now fumes are flowing back into your home. The odor may permeate the entire house, endangering your family’s health if you let it continue. So shut down the furnace and contact a professional right away to request furnace repair. 

The Furnace Smells Like Burning Plastic 

Overheating and melting electrical components are the most plausible reason for a burning plastic smell to come from your furnace. A failing fan motor is another common cause. If you don’t address the problem, an electrical fire could start, or your furnace could experience irreparable damage. Turn off the heating system immediately and call an HVAC technician for help troubleshooting and repairing this weird furnace smell. 

The Furnace Has an Oily Smell 

If you have an oil furnace, you could detect this odor whenever the oil filter becomes clogged. Try replacing it to see if that fixes the problem. If the smell lingers for more than a day after completing this step, it could imply an oil leak. You should get help from an HVAC expert to fix this problem. 

The Furnace Reeks of Sewer Odors 

Sewer gas smells quite similar to rotten eggs, so first rule out the possibility of a natural gas leak. If that’s not the problem, your sewer lines could have an issue, such as a dry trap or sewer leak. Flush water down all your drains, including the basement floor drain, to fill dried-out sewer traps. If the smell persists, you should contact a sewer line repair company. 

Contact Golden Seal Service Experts for Furnace Repair 

When in doubt, contact an HVAC technician to check and repair your furnace. At Golden Seal Service Experts, we perform complete diagnostic services to pinpoint the problem before the work begins. Then, we recommend the most viable, cost-effective repairs, as well as an up-front estimate for every option. Our ACE-certified technicians can resolve 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 Golden Seal Service Experts office today.