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 unusual furnace smells floating in the air. Learn about what the most common furnace smells could mean and how proactive you should be about them. 

The Furnace Smells Musty 

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

A damp air filter can lead to 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 mounted near the furnace might be the root of the problem. This component gathers condensation, which will sometimes trigger mold growth. You’ll be better off with a professional’s help to inspect and clean the evaporator coil. When the problem still won’t go away, consider investing in air duct cleaning. This service removes hidden mold, regardless of where it’s hiding in your ventilation. 

The Furnace Smells Like Rotten Eggs 

This is one of the most nerve-wracking furnace smells since it most likely indicates a gas leak. The utility company includes a useful substance known as mercaptan to the natural gas supply to make leaks easier to detect. 

If you notice a rotten egg smell around your furnace or coming from your vents, switch off the heater right away. If you remember where the main gas supply valve is located, shut that off as well. Then, get out of the house and contact 911, in addition to 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 discover a sour smell that stings your nose while standing near64} the furnace, this may mean the heat exchanger is cracked. This essential component houses68} combustion fumes, such as carbon monoxide, so cracks might spew unsafe levels of CO gas into your home. 

Carbon monoxide poisoning can be lethal, so switch off your furnace right away if you recognize a sour odor. Then, call an HVAC professional for an inspection. Consider replacing your furnace if a cracked heat exchanger is to blame. For your health and safety going forward, make sure you have working CO detectors on every floor of your home. 

The Furnace Smells Dusty 

When you start the furnace for the first time after a while, you should expect a dusty odor to show up for a brief moment. 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 disperses within one day, you don’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 to the exterior. A smoky smell will sometimes mean the flue is clogged, and now fumes are settling back into your home. The odor can reach through the entire house, jeopardizing your family’s health if you ignore it. So switch off the furnace and call a professional straightaway 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 appear. A failing fan motor is also possible. If you don’t tackle the problem, an electrical fire could start, or your furnace could end up with irreparable damage. Turn off the heating system right away and contact an HVAC technician for help troubleshooting and repairing this unusual furnace smell. 

The Furnace Has an Oily Smell 

If you have an oil furnace, you may notice this stench if the oil filter becomes clogged. Try replacing it to determine if that resolves the problem. If the smell persists for more than a day after carrying out this step, it could suggest an oil leak. You’ll be better off with help from an HVAC expert to fix 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 issue, your home’s sewer lines could have an issue, for example a dry trap or sewer leak. Try pouring water down the drains, including the basement floor drain, to fill dried-up sewer traps. If the smell lingers, you should contact a sewer line repair company. 

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

When in doubt, contact an HVAC technician to examine 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 recommend the most viable, cost-effective repairs, along with an up-front estimate for every option. 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 ask questions 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.