Why Your Furnace Has a Strange Smell

As the weather cools down and you swap 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 them.

The Furnace Smells Musty

Musty furnace smells almost always imply mold growth someplace in the HVAC system. To avoid exposing your family to mold and mildew spores, tackle this problem as soon as possible.

A wet air filter can lead to mold, so eliminating the smell can be as easy as swapping out filter. If that doesn't help, the AC evaporator coil fastened near the furnace might be the culprit. This component accumulates condensation, which could induce mold growth. You’ll need a professional’s help to check and clean the evaporator coil. When this still doesn't help, take a look at investing in air duct cleaning. This service removes hidden mold, regardless of where it's hiding in your ductwork.

The Furnace Smells Like Rotting Eggs

This is one of the most worrisome furnace smells because it probably suggests a gas leak. The utility company adds a useful substance called mercaptan to the natural gas supply to make leaks easier to detect.

If you recognize a rotten egg smell around your furnace or coming from your air ducts, shut off the heater right away. If you know where the main gas supply valve is placed, shut that off as well. Then, leave the house and dial 911, in addition to your gas company. Don’t enter 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 close to the furnace, this could mean the heat exchanger cracked open. This important component contains combustion fumes, including carbon monoxide, so a cracked heat exchanger may pump unsafe levels of CO gas into your home.

Carbon monoxide poisoning can be lethal, so switch off your furnace immediately if you detect a sour odor. Then, contact an HVAC professional for an inspection. Consider replacing your furnace if a cracked heat exchanger is the culprit. For your family's safety going forward, see to it that you have reliable CO detectors on each floor of your home.

The Furnace Smells Dusty

When you fire up the furnace for the first time after a while, you probably expect a dusty odor to fill the house for a little while. This is the smell of six months’ worth of dust burning off as the furnace wakes up. As long as the smell goes away within a 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 could mean the flue is clogged, and now fumes are settling back into your home. The odor might eventually reach the entire house, endangering your family’s health if you neglect it. So shut down the furnace and get in touch with a professional right away to schedule a repair.

The Furnace Smell Resembles Burning Plastic

Overheating and melted electrical components are the most common reason for a burning plastic smell to make an appearance. A failing fan motor is also possible. If you don’t address the problem, an electrical fire might start, or your furnace could suffer from irreparable damage. Turn off the heating system as soon as possible and contact an HVAC technician for help identifying and repairing this weird furnace smell.

The Furnace Has an Oily Smell

If you own an oil furnace, you could pick up on this stench when the oil filter becomes blocked up. Try replacing it to determine if that addresses the problem. If the smell lingers for more than a day after taking care of this step, it may suggest an oil leak. You’ll need help from an HVAC professional to address this problem.

The Furnace Reeks of Sewer Odors

Sewer gas smells quite similar to rotting eggs, so first eliminate the likelihood of a natural gas leak. If that’s not the source, your sewer lines might have an issue, for example a dry trap or sewer leak. Try pouring water down the drains, including the basement floor drain, to refresh dry sewer traps. If the smell persists, go ahead and contact a sewer line repair company.

Contact Service Experts Heating & Air Conditioning for Furnace Repair

When in doubt, get in touch with an HVAC technician to check and repair your furnace. At Service Experts Heating & Air Conditioning, we deliver complete diagnostic services to identify the problem before repairs begin. Then, we suggest the most viable, cost-effective repairs, as well as an up-front estimate for every option. Our ACE-certified technicians can resolve just about any heating repair, 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 Service Experts Heating & Air Conditioning office today.

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