Why Your Furnace Has a Strange Smell

As the weather turns cold and you transition from cooling to heating your home, you may be worried about weird furnace smells in the air. Learn what the most common furnace smells mean and how proactive 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 damp air filter can harbor mold, so wiping out the smell can be as straightforward as replacing the filter. If that fails to remove the smell, the AC evaporator coil placed near the furnace could be the root of the problem. This component accumulates condensation, which can trigger mold growth. You’ll need a professional’s help to examine and clean the evaporator coil. When this still doesn't help, take a look at requesting air duct cleaning. This service eliminates hidden mold, no matter where it's hiding in your ventilation.

The Furnace Smells Like Rotting Eggs

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

If you recognize a rotten egg smell around your furnace or originating from your vents, shut off the heater straightaway. If you know where the main gas supply valve is located, shut that off as well. Then, leave the house and call 911, as well as your gas company. Don’t enter the house until a professional can verify it’s safe.

The Furnace Has a Sour Stench

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

Carbon monoxide poisoning can be fatal, so turn off your furnace right away if you notice 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 continued safety going forward, make sure you have working CO detectors on each floor of your home.

The Furnace Smells Dusty

When you start the furnace for the first time every fall, you can expect a dusty odor to show up for a few minutes. This is the smell of six months’ worth of dust burning up as the furnace wakes from its summer slumber. As long as the smell dissipates within a day, you shouldn'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 up and out of your home. A smoky smell can mean the flue is clogged, and now fumes are backdrafting into your home. The odor might eventually reach the entire house, risking your family’s health if you neglect it. So shut down the furnace and call a professional right away to arrange for repair.

The Furnace Smells Like Burning Plastic

Overheating and melting electrical components are the most plausible reason for a burning plastic smell to appear. A faulty fan motor is another common cause. If you don’t correct the problem, an electrical fire may start, or your furnace could experience irreparable damage. Shut off the heating system right away and call an HVAC technician for help identifying and repairing this unpleasant furnace smell.

The Furnace Has an Oily Smell

If you have an oil furnace, you could pick up on this odor if the oil filter becomes clogged. Try replacing it to see if that fixes the problem. If the smell persists for more than 24 hours after carrying out this step, it may indicate an oil leak. You'll be better off with help from an HVAC professional to handle this problem.

The Furnace Smells Like Sewer Odors

Sewer gas smells quite similar to rotting eggs, so first rule out the potential for a natural gas leak. If that’s not the problem, your home's sewer lines might have an issue, like a dry trap or sewer leak. Try pouring water down all your drains, including the basement floor drain, to refresh dried-up sewer traps. If the smell persists, you’ll need to contact a sewer line repair company.

Contact Service Experts Heating & Air Conditioning for Furnace Repair

If you're still uncertain, call an HVAC technician to examine and repair your furnace. At Service Experts Heating & Air Conditioning, we deliver complete diagnostic services to pinpoint the problem before repairs begin. Then, we suggest the most viable, cost-effective repairs, along with an up-front estimate for every 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 learn more about why your furnace smells bad or to request furnace repair near you, please contact your local Service Experts Heating & Air Conditioning office today.

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