Why Your Furnace Has a Strange Smell

As the weather turns cold and you transition from cooling to heating your home, you might be worried about unusual furnace smells floating in the air. Learn about what the most common furnace smells could mean and how worried you should be about each one. 

The Furnace Smells Musty 

Musty furnace smells usually indicate mold growth hiding in the HVAC system. To avoid subjecting your family to allergy-inducing mold, handle this problem right away. 

A damp air filter can harbor mold, so wiping out the smell could be as easy as swapping out filter. If that doesn’t help, the AC evaporator coil fastened near the furnace might be the culprit. This component gathers condensation, which will sometimes induce mold growth. You’ll need a professional’s help to inspect and clean the evaporator coil. When the problem still won’t go away, take a look at scheduling air duct cleaning. This service eliminates hidden mold, no matter where it’s hiding in your ductwork. 

The Furnace Smells Like Rotting Eggs 

This is one of the most worrisome furnace smells due to the fact that it probably indicates a gas leak. The utility company includes a special substance known as mercaptan to the natural gas supply to make leaks easier to detect. 

If you detect a rotten egg smell near your furnace or coming from your vents, switch off the heater immediately. If you remember where the main gas supply valve is located, shut that off too. Then, leave the house and call 911, as well as your gas company. Don’t go back in the house until a professional can verify it’s safe. 

The Furnace Has a Sour Stench 

If you detect a sour smell that stings your nose while standing close to64} the furnace, this might mean the heat exchanger is cracked. This important component safely contains68} combustion fumes, such as carbon monoxide, so cracks may pump unsafe levels of CO gas into your home. 

Carbon monoxide poisoning could be lethal, so shut off your furnace as soon as possible if you notice a sour odor. Then, call an HVAC professional for an inspection. Consider replacing your furnace if a cracked heat exchanger is the culprit. For your health and safety going forward, ensure you have working CO detectors on each floor of your home. 

The Furnace Smells Dusty 

When you turn on the furnace for the first time each fall, you should expect a dusty odor to appear for a few minutes. This is the smell of six months’ worth of dust burning off as the furnace wakes from its summer slumber. 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 to the exterior. A smoky smell will sometimes mean the flue is clogged, and now fumes are backdrafting into your home. The odor might eventually reach the entire house, endangering your family’s health if you ignore it. So turn off the furnace and get in touch with a professional as soon as you can to schedule a repair. 

The Furnace Smell Resembles Burning Plastic 

Overheating and melting electrical components are the most likely reason for a burning plastic smell to come from your furnace. A malfunctioning fan motor is another possibility. If you don’t address the problem, an electrical fire might start, or your furnace could experience irreparable damage. Shut off the heating system as soon as possible and call an HVAC technician for help troubleshooting and repairing this unpleasant furnace smell. 

The Furnace Has an Oily Smell 

If you use an oil furnace, you might detect this smell when the oil filter becomes clogged. Try replacing it to determine if that addresses the problem. If the smell remains for more than a day after completing this step, it might indicate an oil leak. You’ll be better off with help from an HVAC specialist to handle this problem. 

The Furnace Reeks of Sewer Odors 

Sewer gas smells very similar to rotten eggs, so first eliminate the potential for a natural gas leak. If that’s not the problem, the sewer lines could have an issue, such as a dry trap or sewer leak. Try pouring water down your own drains, including the basement floor drain, to fill dried-up sewer traps. If the smell lingers, you should contact a sewer line repair company. 

Contact Bryant Heating & Cooling Service Experts for Furnace Repair 

If you’re still unsure, contact an HVAC technician to assess and repair your furnace. At Bryant Heating & Cooling Service Experts, 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 every option. Our 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 Bryant Heating & Cooling Service Experts office today.