Why Your Furnace Has a Strange Smell

As the weather gets colder and you transition from cooling to heating your home, you may be worried about weird furnace smells floating in the air. Learn about what the most common furnace smells mean and how worried you should be about them. 

The Furnace Smells Musty 

Musty furnace smells generally 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 clogged air filter can harbor mold, so getting rid of the smell can be as easy as getting a new filter. If that fails to remove the smell, the AC evaporator coil mounted near the furnace might be the culprit. This component collects condensation, which can induce mold growth. You’ll be better off with a professional’s help to inspect and clean the evaporator coil. When this still doesn’t help, take a look at requesting air duct cleaning. This service eliminates hidden mold, regardless of where it’s hiding in your ventilation. 

The Furnace Smells Like Rotten Eggs 

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

If you detect a rotten egg smell around your furnace or coming from your vents, shut off the heater right away. If you know where the main gas supply valve is located, shut that off too. Then, leave the house and contact 911, as well as your gas company. Don’t go back in 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 near64} the furnace, this may mean the heat exchanger is cracked. This vital component contains68} combustion fumes, like carbon monoxide, so cracks may spew unsafe levels of CO gas into your home. 

Carbon monoxide poisoning could be fatal, so turn off your furnace as soon as possible if you notice a sour odor. Then, contact 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 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 should expect a dusty odor to appear for a little while. This is the smell of six months’ worth of dust burning off as the furnace wakes from its summer slumber. As long as the smell dissipates 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 safely out of your home. A smoky smell could mean the flue is clogged, and now fumes are backdrafting into your home. The odor may permeate the entire house, risking your family’s health if you ignore it. So shut down the furnace and call a professional right away to schedule a repair. 

The Furnace Smells Like It’s Burning Plastic 

Overheating and melting electrical components are the most plausible reason for a burning plastic smell to come from your furnace. A malfunctioning fan motor is another possibility. If you don’t address the problem, an electrical fire might start, or your furnace could end up with irreparable damage. Disable the heating system right away and call an HVAC technician for help identifying and repairing this unusual furnace smell. 

The Furnace Has an Oily Smell 

If you use an oil furnace, you could notice this stench whenever the oil filter becomes blocked up. Try replacing it to find out if that fixes the problem. If the smell lingers for more than one day after taking care of this step, it could imply an oil leak. You’ll need help from an HVAC expert to handle this problem. 

The Furnace Smell Resembles Sewer Odors 

Sewer gas smells pretty similar to rotten eggs, so first rule out the potential for a natural gas leak. If that’s not the source, the sewer lines might have an issue, such as a dry trap or sewer leak. Try pouring water down all your drains, including the basement floor drain, to refresh dry sewer traps. If the smell persists, you’ll need to 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 check and repair your furnace. At Service Experts Heating, Air Conditioning & Plumbing, we perform 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 every option. 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 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.