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 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 almost always 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 indicates a gas leak. The utility company includes a useful substance known as mercaptan to the natural gas supply to make leaks easier to detect. 

If you notice a rotten egg smell around your furnace or coming from your vents, shut off the heater immediately. If you know where the main gas supply valve is, shut that off as well. Then, leave the house and call 911, followed by your gas company. Don’t enter the house until a professional tells you 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 is cracked. This vital component safely contains68} combustion fumes, including carbon monoxide, so a crack could pump unsafe levels of CO gas into your home. 

Carbon monoxide poisoning can be deadly, so shut off your furnace right away if you detect 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 continued safety going forward, make sure you have functional 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 can expect a dusty odor to fill the house for a little while. This is the smell of six months’ worth of dust burning away as the furnace wakes from its summer slumber. As long as the smell dissipates within one 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 settling back into your home. The odor may permeate the entire house, risking your family’s health if you neglect it. So turn off the furnace and call a professional right away to schedule a repair. 

The Furnace Smells Like It’s Burning Plastic 

Overheating and melting electrical components are the most likely reason for a burning plastic smell to make an appearance. A failing fan motor is another possibility. 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 own an oil furnace, you might pick up on this odor if 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’ll need help from an HVAC expert to address 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. Pour water down all your drains, including the basement floor drain, to replenish dry sewer traps. If the smell lingers, go ahead and contact a sewer line repair company. 

Contact Chief/Bauer Service Experts for Furnace Repair 

When in doubt, contact an HVAC technician to examine and repair your furnace. At Chief/Bauer Service Experts, we deliver complete 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 Chief/Bauer Service Experts office today.