As the weather gets colder and you transition from cooling to heating your home, you may be worried about strange furnace smells floating in the air. Learn about what the most common furnace smells mean and how concerned you should be about them.
The Furnace Smells Musty
Musty furnace smells almost always suggest mold growth hiding in the HVAC system. To avoid subjecting your family to allergy-inducing mold, handle this problem as quickly as possible.
A wet air filter can lead to mold, so wiping out the smell could be as straightforward as swapping out filter. If that doesn’t work, the AC evaporator coil fastened near the furnace may be to blame. This component accumulates condensation, which could trigger mold growth. You'll be better off with a professional’s help to examine and clean the evaporator coil. When the problem still won't go away, consider investing in air duct cleaning. This service cleans away hidden mold, regardless of where it's hiding in your ventilation.
The Furnace Smells Like Rotting Eggs
This is one of the most nerve-wracking furnace smells since it most likely suggests a gas leak. The utility company includes a useful substance known as mercaptan to the natural gas supply to make leaks easier to notice.
If you recognize a rotten egg smell around your furnace or out of your vents, shut down the heater straightaway. If you know where the main gas supply valve is, shut that off as well. Then, leave the house and contact 911, followed by your gas company. Don’t reenter the house until a professional tells you it’s safe.
The Furnace Has a Sour Stench
If you discover a sour smell that stings your nose while close to the furnace, this may mean the heat exchanger has cracked. This essential component houses combustion fumes, including carbon monoxide, so a crack may spew unsafe levels of CO gas into your home.
Carbon monoxide poisoning can be lethal, so shut off your furnace right away if you notice a sour odor. Then, reach out to 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 functional CO detectors on each 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 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 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 blocked, and now fumes are backdrafting into your home. The odor can reach through the entire house, jeopardizing your family’s health if you let it continue. So shut down the furnace and call a professional as soon as you can to request furnace repair.
The Furnace Smells Like Burning Plastic
Overheating and melted electrical components are the most common reason for a burning plastic smell to appear. A malfunctioning fan motor is another common cause. If you don’t correct the problem, an electrical fire might start, or your furnace could end up with irreparable damage. Turn off the heating system immediately and call an HVAC technician for help diagnosing and repairing this unusual furnace smell.
The Furnace Has an Oily Smell
If you own an oil furnace, you might notice this odor whenever the oil filter becomes clogged. Try replacing it to see if that fixes the problem. If the smell remains for more than one day after carrying out this step, it could indicate an oil leak. You'll be better off with help from an HVAC specialist to fix this problem.
The Furnace Reeks of Sewer Odors
Sewer gas smells pretty similar to rotting eggs, so first rule out the potential for a natural gas leak. If that’s not the source, your home's sewer lines might have an issue, for example a dry trap or sewer leak. Flush water down your own drains, including the basement floor drain, to replenish dried-out sewer traps. If the smell lingers, go ahead and contact a sewer line repair company.
Contact Finch Air Conditioning & Heating for Furnace Repair
If you're still uncertain, contact an HVAC technician to examine and repair your furnace. At Finch Air Conditioning & Heating, we offer comprehensive 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 each option. Our ACE-certified technicians can handle just about any heating malfunction, and we back our work with a 100% satisfaction guarantee for one year. To ask questions about why your furnace smells bad or to request furnace repair near you, please contact your local Finch Air Conditioning & Heating office today.