Why Your Furnace Has a Strange Smell

As the weather cools down and you switch from cooling to heating your home, you may be worried about weird furnace smells in the air. Find out what the most common furnace smells mean and how worried you should be about them.

The Furnace Smells Musty

Musty furnace odors almost always suggest mold growth somewhere in the HVAC system. To avoid subjecting your family to these microorganisms, handle this problem as quickly as possible.

A clogged air filter can harbor mold, so wiping out the smell might be as straightforward as replacing the filter. If that doesn't help, the AC evaporator coil fastened near the furnace may be the root of the problem. This component gathers condensation, which could trigger mold growth. You'll be better off with a professional’s help to examine and clean the evaporator coil. When all else fails, consider requesting air duct cleaning. This service eliminates hidden mold, no matter where it's hiding in your ductwork.

The Furnace Smells Like Spoiled Eggs

This is one of the most concerning furnace smells since it probably indicates a gas leak. The utility company adds a special substance known as mercaptan to the natural gas supply to make leaks easier to detect.

If you recognize a rotten egg smell near your furnace or coming from your air ducts, shut down the heater straightaway. If you know where the main gas supply valve is located, shut that off as well. Then, get out of the house and call 911, as well as your gas company. Don’t go back in 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 standing near the furnace, this might mean the heat exchanger cracked open. This important component houses combustion fumes, such as carbon monoxide, so cracks could pump unsafe levels of CO gas into your home.

Carbon monoxide poisoning could be deadly, so turn off your furnace right away if you recognize a sour odor. Then, contact an HVAC professional for an inspection. Consider replacing your furnace if a cracked heat exchanger is to blame. For your health and safety going forward, ensure you have reliable CO detectors on each floor 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 fill the house for a few minutes. This is the smell of six months’ worth of dust burning up as the furnace wakes up. As long as the smell dissipates within a 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 could mean the flue is blocked, and now fumes are flowing back into your home. The odor may permeate the entire house, endangering your family’s health if you ignore it. So shut down the furnace and get in touch with a professional right away to request furnace repair.

The Furnace Smells Like It's Burning Plastic

Overheating and melted electrical components are the most plausible reason for a burning plastic smell to come from your furnace. A faulty fan motor is also possible. If you don’t correct the problem, an electrical fire may start, or your furnace could experience irreparable damage. Disable the heating system right away and contact 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 may detect this odor if the oil filter becomes clogged. Try replacing it to determine if that addresses the problem. If the smell lingers for more than one day after carrying out this step, it may suggest an oil leak. You'll be better off with help from an HVAC expert to address this problem.

The Furnace Smells Like Sewer Odors

Sewer gas smells quite similar to rotting eggs, so first eliminate the possibility of a natural gas leak. If that’s not the source, the sewer lines might have an issue, like a dry trap or sewer leak. Flush 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 Roland J. Down Service Experts for Furnace Repair

When in doubt, call an HVAC technician to examine and repair your furnace. At Roland J. Down Service Experts , we deliver complete diagnostic services to determine the problem before we figure out the best solution. Then, we encourage the most viable, cost-effective repairs, as well as an up-front estimate for all options. Our ACE-certified technicians can manage just about any heating repair, 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 Roland J. Down Service Experts office today.

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