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 about what the most common furnace smells could suggest and how proactive you should be about each one.

The Furnace Smells Musty

Musty furnace smells generally suggest mold growth somewhere in the HVAC system. To avoid subjecting your family to allergy-inducing mold, handle this problem as soon as possible.

A damp air filter can harbor mold, so getting rid of the smell could be as straightforward as swapping out filter. If that doesn’t work, the AC evaporator coil fastened near the furnace could be the culprit. This component collects condensation, which can induce mold growth. You'll want a professional’s help to check and clean the evaporator coil. When the problem still won't go away, start thinking about scheduling air duct cleaning. This service eliminates hidden mold, no matter where it’s growing in your ventilation.

The Furnace Smells Like Spoiled Eggs

This is one of the most concerning furnace smells since it probably implies a gas leak. The utility company puts in a special substance called mercaptan to the natural gas supply to make leaks more easily detected.

If you recognize a rotten egg smell close to your furnace or coming from your vents, shut down the heater immediately. If you remember where the main gas supply valve is, shut that off too. Then, evacuate your home and call 911, as well as your gas company. Don’t reenter the house until a professional tells you it’s safe.

The Furnace Has a Sour Stench

If you notice a sour smell that stings your nose while close to the furnace, this might mean the heat exchanger cracked open. This vital component houses combustion fumes, including carbon monoxide, so cracks may pump unsafe levels of CO gas into your home.

Carbon monoxide poisoning has the potential to be fatal, 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 responsible. For your family's safety going forward, ensure you have functional CO detectors on all floors of your home.

The Furnace Smells Dusty

When you start the furnace for the first time each fall, you probably expect a dusty odor to appear for a brief moment. This is the smell of six months’ worth of dust burning up as the furnace wakes up. As long as the smell dissipates within 24 hours, 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 may permeate the entire house, jeopardizing your family’s health if you let it continue. So shut down the furnace and contact a professional as soon as you can to arrange for repair.

The Furnace Smells Like Burning Plastic

Overheating and melted electrical components are the most plausible reason for a burning plastic smell to appear. A malfunctioning fan motor is also possible. If you don’t correct the problem, an electrical fire may start, or your furnace could end up with irreparable damage. Shut off the heating system right away and call an HVAC technician for help troubleshooting and repairing this unusual furnace smell.

The Furnace Has an Oily Smell

If you use an oil furnace, you might notice this stench whenever the oil filter becomes blocked up. Try replacing it to determine if that resolves the problem. If the smell remains for more than a day after taking care of this step, it could suggest an oil leak. You’ll need help from an HVAC expert to address this problem.

The Furnace Smells Like Sewer Odors

Sewer gas smells pretty similar to spoiled eggs, so first determine the possibility of a natural gas leak. If that’s not the source, your sewer lines might have an issue, such as a dry trap or sewer leak. Pour water down all your drains, including the basement floor drain, to replenish dried-out sewer traps. If the smell sticks around, you should contact a sewer line repair company.

Contact Rob's Albertan Service Experts for Furnace Repair

If you're still uncertain, contact an HVAC technician to check and repair your furnace. At Rob's Albertan Service Experts, we perform thorough diagnostic services to determine the problem before the work begins. Then, we encourage the most viable, cost-effective repairs, as well as an up-front estimate for all options. 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 Rob's Albertan Service Experts office today.

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