Why Your Furnace Has a Strange Smell

As the weather cools down and you switch from cooling to heating your home, some homeowners are worried about weird furnace smells filling the air. Learn about what the most common furnace smells could mean and how proactive you should be about each one. 

The Furnace Smells Musty 

Musty furnace odors usually indicate mold growth hiding in the HVAC system. To avoid subjecting your family to allergy-inducing mold, handle this problem as quickly as possible. 

A wet air filter can lead to mold, so getting rid of the smell could be as straightforward as swapping out filter. If that fails to remove the smell, the AC evaporator coil fastened near the furnace could be to blame. This component gathers condensation, which could induce mold growth. You’ll want a professional’s help to inspect and clean the evaporator coil. When this still doesn’t help, take a look at scheduling air duct cleaning. This service cleans away hidden mold, regardless of where it’s growing in your air ducts. 

The Furnace Smells Like Rotten Eggs 

This is one of the most concerning furnace smells due to the fact that it frequently implies a gas leak. The utility company puts in a useful substance called mercaptan to the natural gas supply to make leaks easier to notice. 

If you notice a rotten egg smell near your furnace or out of your air ducts, switch off the heater straightaway. If you know where the main gas supply valve is located, shut that off too. Then, evacuate your home and contact 911, followed by 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 notice a sour smell that stings your nose while standing near64} the furnace, this may mean the heat exchanger is cracked. This essential component safely contains68} combustion fumes, like carbon monoxide, so cracks may spew unsafe levels of CO gas into your home. 

Carbon monoxide poisoning could be deadly, so turn off your furnace as soon as possible if you notice a sour odor. Then, reach out to an HVAC professional for an inspection. Consider replacing your furnace if a cracked heat exchanger is responsible. For your health and safety going forward, see to it that you have reliable CO detectors on all floors of your home. 

The Furnace Smells Dusty 

When you start the furnace for the first time each fall, you should expect a dusty odor to appear for a little while. This is the smell of six months’ worth of dust burning up as the furnace wakes up. As long as the smell goes away within one 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 will sometimes mean the flue is blocked, and now fumes are flowing back into your home. The odor might eventually reach the entire house, risking your family’s health if you neglect it. So switch off the furnace and call a professional straightaway to arrange for repair. 

The Furnace Smells Like Burning Plastic 

Overheating and melting electrical components are the most common reason for a burning plastic smell to come from your furnace. A malfunctioning fan motor is also possible. If you don’t tackle the problem, an electrical fire may start, or your furnace could experience irreparable damage. Turn off the heating system as soon as possible and contact an HVAC technician for help diagnosing and repairing this unusual furnace smell. 

The Furnace Has an Oily Smell 

If you have an oil furnace, you could detect this smell when the oil filter becomes clogged. Try replacing it to find out if that resolves the problem. If the smell lingers for more than one day after carrying out this step, it might indicate an oil leak. You should get help from an HVAC expert to address this problem. 

The Furnace Smell Resembles Sewer Odors 

Sewer gas smells very similar to rotting eggs, so first eliminate the likelihood of a natural gas leak. If that’s not the source, the sewer lines may have an issue, such as a dry trap or sewer leak. Pour water down the drains, including the basement floor drain, to replenish 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, call an HVAC technician to examine and repair your furnace. At Service Experts Heating, Air Conditioning & Plumbing, we perform comprehensive diagnostic services to identify the problem before repairs begin. Then, we recommend the most viable, cost-effective repairs, alongside an up-front estimate for each 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. 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.