Why Your Furnace Has a Strange Smell

As the weather turns cold and you transition from cooling to heating your home, some homeowners are worried about weird furnace smells floating in the air. Learn about 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 suggest mold growth somewhere in the HVAC system. To avoid subjecting your family to mold and mildew spores, handle this problem as quickly as possible. 

A clogged air filter can harbor mold, so getting rid of the smell could be as simple as getting a new filter. If that fails to remove the smell, the AC evaporator coil placed near the furnace could be the root of the problem. This component accumulates condensation, which could induce mold growth. You’ll need a professional’s help to inspect and clean the evaporator coil. When this still doesn’t help, take a look at scheduling air duct cleaning. This service cleans away hidden mold, no matter where it’s hiding in your ductwork. 

The Furnace Smells Like Rotten Eggs 

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

If you detect a rotten egg smell around your furnace or out of your vents, shut off the heater right away. If you remember where the main gas supply valve is located, shut that off too. Then, get out of the house and contact 911, as well as your gas company. Don’t reenter 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 near64} the furnace, this could mean the heat exchanger is cracked. This essential component houses68} combustion fumes, like carbon monoxide, so a crack might pump unsafe levels of CO gas into your home. 

Carbon monoxide poisoning has the potential to be lethal, so shut off your furnace as soon as possible if you recognize a sour odor. Then, contact an HVAC professional for an inspection. Consider replacing your furnace if a cracked heat exchanger is the culprit. For your continued safety going forward, see to it that you have working CO detectors on each floor of your home. 

The Furnace Smells Dusty 

When you fire up the furnace for the first time each fall, you should expect a dusty odor to show up for a brief moment. 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 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 safely out of your home. A smoky smell can mean the flue is clogged, and now fumes are flowing back into your home. The odor may permeate the entire house, risking your family’s health if you let it continue. So switch off the furnace and contact a professional right away to schedule a repair. 

The Furnace Smell Resembles Burning Plastic 

Overheating and melted electrical components are the most likely reason for a burning plastic smell to make an appearance. A faulty fan motor is another possibility. If you don’t tackle the problem, an electrical fire could start, or your furnace could suffer from irreparable damage. Disable the heating system as soon as possible and call an HVAC technician for help diagnosing and repairing this weird furnace smell. 

The Furnace Has an Oily Smell 

If you have an oil furnace, you could pick up on this smell if the oil filter becomes clogged. Try replacing it to determine if that fixes the problem. If the smell remains for more than a day after completing this step, it could indicate an oil leak. You’ll be better off with help from an HVAC professional to address this problem. 

The Furnace Smell Resembles Sewer Odors 

Sewer gas smells quite similar to rotting eggs, so first eliminate the potential for a natural gas leak. If that’s not the source, the sewer lines may have an issue, for example a dry trap or sewer leak. Pour water down your own drains, including the basement floor drain, to fill dried-up sewer traps. If the smell sticks around, you should contact a sewer line repair company. 

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

When in doubt, get in touch with an HVAC technician to examine and repair your furnace. At Service Experts Heating, Air Conditioning & Plumbing, we offer thorough diagnostic services to identify the problem before we figure out the best solution. Then, we recommend the most viable, cost-effective repairs, as well as 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.