Why Your Furnace Has a Strange Smell

As the weather turns cold and you swap from cooling to heating your home, some homeowners are worried about weird furnace smells filling the air. Find out what the most common furnace smells mean and how concerned you should be about them. 

The Furnace Smells Musty 

Musty furnace odors usually suggest mold growth somewhere in the HVAC system. To avoid exposing your family to these microorganisms, address this problem as soon as possible. 

A clogged air filter can harbor mold, so getting rid of the smell can be as simple as replacing the filter. If that fails to remove the smell, the AC evaporator coil fastened near the furnace might be the culprit. This component gathers condensation, which will sometimes trigger mold growth. You’ll want a professional’s help to examine and clean the evaporator coil. When the problem still won’t go away, take a look at investing in air duct cleaning. This service eliminates hidden mold, regardless of where it’s growing in your ductwork. 

The Furnace Smells Like Spoiled Eggs 

This is one of the most worrisome furnace smells because it probably indicates a gas leak. The utility company puts in a special substance known as mercaptan to the natural gas supply to make leaks more easily detected. 

If you recognize a rotten egg smell around your furnace or originating from your ductwork, shut off the heater immediately. If you know where the main gas supply valve is located, shut that off also. Then, leave the house and dial 911, followed by your gas company. Don’t go back in 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 near64} the furnace, this could mean the heat exchanger is cracked. This essential component contains68} combustion fumes, like carbon monoxide, so cracks might spew unsafe levels of CO gas into your home. 

Carbon monoxide poisoning could be lethal, 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 the culprit. For your family’s safety going forward, make sure you have functional CO detectors on every 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 appear for a brief moment. 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 24 hours, 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 up and out of your home. A smoky smell could mean the flue is clogged, and now fumes are backdrafting into your home. The odor can reach through the entire house, jeopardizing your family’s health if you neglect it. So switch off the furnace and get in touch with a professional right away to arrange for 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 failing fan motor is another common cause. If you don’t tackle the problem, an electrical fire might start, or your furnace could experience irreparable damage. Shut 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 have an oil furnace, you might 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 remains 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 expert to address this problem. 

The Furnace Smells Like Sewer Odors 

Sewer gas smells pretty similar to rotting eggs, so first rule out the likelihood of a natural gas leak. If that’s not the problem, your home’s sewer lines could have an issue, for example a dry trap or sewer leak. Flush water down the drains, including the basement floor drain, to replenish dried-up sewer traps. If the smell lingers, go ahead and contact a sewer line repair company. 

Contact Service Experts Heating, Air Conditioning & Plumbing for Furnace Repair 

If you’re still uncertain, get in touch with an HVAC technician to examine and repair your furnace. At Service Experts Heating, Air Conditioning & Plumbing, we offer 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 all options. Our ACE-certified technicians can resolve just about any heating malfunction, 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 & Plumbing office today.