Why Your Furnace Has a Strange Smell

As the weather cools down and you transition from cooling to heating your home, you might be worried about weird furnace smells floating in the air. Find out what the most common furnace smells mean and how proactive you should be about each one.

The Furnace Smells Musty

Musty furnace smells generally imply mold growth hiding in the HVAC system. To avoid subjecting your family to mold and mildew spores, tackle this problem right away.

A wet air filter can lead to mold, so eliminating the smell can be as straightforward as getting a new filter. If that doesn't help, the AC evaporator coil fastened near the furnace could be the culprit. This component collects 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, consider investing in air duct cleaning. This service removes hidden mold, no matter where it's hiding in your air ducts.

The Furnace Smells Like Spoiled Eggs

This is one of the most concerning furnace smells due to the fact that it frequently suggests a gas leak. The utility company includes a particular substance called mercaptan to the natural gas supply to make leaks easier to notice.

If you notice a rotten egg smell close to your furnace or originating from your ductwork, shut down the heater immediately. If you can find where the main gas supply valve is located, shut that off too. Then, evacuate your home and contact 911, followed by your gas company. Don’t reenter the house until a professional confirms it’s safe.

The Furnace Has a Sour Stench

If you detect a sour smell that stings your nose while standing near the furnace, this may mean the heat exchanger cracked open. This important component safely contains combustion fumes, such as carbon monoxide, so a cracked heat exchanger might allow unsafe levels of CO gas into your home.

Carbon monoxide poisoning could be fatal, so turn off your furnace immediately if you detect a sour odor. Then, call an HVAC professional for an inspection. Consider replacing your furnace if a cracked heat exchanger is responsible. For your family's safety going forward, make sure you have working CO detectors on all floors of your home.

The Furnace Smells Dusty

When you turn on the furnace for the first time after a while, you can expect a dusty odor to fill the house for a few minutes. This is the smell of six months’ worth of dust burning away as the furnace wakes up. As long as the smell disperses within one day, you don't have anything 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 backed up, and now fumes are flowing back into your home. The odor can reach through the entire house, jeopardizing your family’s health if you let it continue. So switch off the furnace and get in touch with a professional as soon as you can to schedule a repair.

The Furnace Smells Like Burning Plastic

Overheating and melting electrical components are the most likely reason for a burning plastic smell to make an appearance. A faulty fan motor is also possible. If you don’t address the problem, an electrical fire could start, or your furnace could suffer from irreparable damage. Shut off the heating system immediately and contact an HVAC technician for help troubleshooting and repairing this weird furnace smell.

The Furnace Has an Oily Smell

If you own an oil furnace, you may detect this odor when the oil filter becomes clogged. Try replacing it to determine if that addresses the problem. If the smell lingers for more than a day after completing this step, it could indicate an oil leak. You should get help from an HVAC professional to handle this problem.

The Furnace Reeks of Sewer Odors

Sewer gas smells very similar to rotten eggs, so first eliminate the possibility of a natural gas leak. If that’s not the problem, your sewer lines could have an issue, such as a dry trap or sewer leak. Pour water down the drains, including the basement floor drain, to fill dry sewer traps. If the smell lingers, go ahead and contact a sewer line repair company.

Contact Peitz Service Experts for Furnace Repair

When in doubt, call an HVAC technician to examine and repair your furnace. At Peitz Service Experts, we deliver complete diagnostic services to determine the problem before we figure out the best solution. Then, we suggest 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 ask questions about why your furnace smells bad or to request furnace repair near you, please contact your local Peitz Service Experts office today.

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