Why Your Furnace Has a Strange Smell

As the weather cools down and you transition from cooling to heating your home, you may be worried about weird furnace smells floating in the air. Learn what the most common furnace smells could suggest and how worried you should be about each one.

The Furnace Smells Musty

Musty furnace smells almost always indicate mold growth someplace in the HVAC system. To avoid exposing your family to allergy-inducing mold, tackle this problem right away.

A wet air filter can encourage mold, so wiping out the smell could be as easy as replacing the filter. If that doesn't help, the AC evaporator coil fastened near the furnace might be to blame. This component gathers condensation, which will sometimes trigger mold growth. You'll be better off with a professional’s help to check and clean the evaporator coil. When this still doesn't help, consider investing in air duct cleaning. This service cleans away hidden mold, no matter where it's hiding in your ventilation.

The Furnace Smells Like Rotting Eggs

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

If you notice a rotten egg smell near your furnace or coming from your air ducts, switch off the heater immediately. If you know where the main gas supply valve is located, shut that off as well. Then, get out of the house and dial 911, in addition to your gas company. Don’t reenter the house until a professional confirms it’s safe.

The Furnace Has a Sour Stench

If you notice a sour smell that stings your nose while standing close to the furnace, this may mean the heat exchanger has cracked. This vital component houses combustion fumes, like carbon monoxide, so a cracked heat exchanger could spew unsafe levels of CO gas into your home.

Carbon monoxide poisoning could be fatal, so shut off your furnace right away if you recognize a sour odor. Then, call an HVAC professional for an inspection. Consider replacing your furnace if a cracked heat exchanger is to blame. For your continued safety going forward, ensure you have reliable CO detectors on all floors of your home.

The Furnace Smells Dusty

When you fire up the furnace for the first time each fall, you probably expect a dusty odor to fill the house 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 disperses 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 safely out of your home. A smoky smell will sometimes mean the flue is clogged, and now fumes are backdrafting into your home. The odor can reach through the entire house, risking your family’s health if you let it continue. So turn off the furnace and get in touch with a professional straightaway to request furnace repair.

The Furnace Smells Like It's Burning Plastic

Overheating and burned electrical components are the most plausible reason for a burning plastic smell to come from your furnace. A faulty fan motor is another possibility. If you don’t correct the problem, an electrical fire might start, or your furnace could suffer from irreparable damage. Shut off the heating system immediately and call an HVAC technician for help identifying and repairing this weird furnace smell.

The Furnace Has an Oily Smell

If you have an oil furnace, you may notice this smell when the oil filter becomes blocked up. Try replacing it to find out if that addresses the problem. If the smell remains for more than a day after taking care of this step, it might suggest an oil leak. You should get help from an HVAC professional to fix this problem.

The Furnace Reeks of Sewer Odors

Sewer gas smells quite similar to spoiled eggs, so first eliminate the potential for a natural gas leak. If that’s not the problem, 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 dry sewer traps. If the smell persists, go ahead and contact a sewer line repair company.

Contact Golden Seal Service Experts for Furnace Repair

When in doubt, call an HVAC technician to examine and repair your furnace. At Golden Seal Service Experts, we deliver complete diagnostic services to pinpoint the problem before repairs begin. Then, we encourage the most viable, cost-effective repairs, along with 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. For details about why your furnace smells bad or to request furnace repair near you, please contact your local Golden Seal Service Experts office today.

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