Why Your Furnace Has a Strange Smell

As the weather gets colder and you switch from cooling to heating your home, you might be worried about strange furnace smells filling the air. Learn what the most common furnace smells could suggest and how concerned you should be about them. 

The Furnace Smells Musty 

Musty furnace odors usually imply mold growth someplace in the HVAC system. To avoid subjecting your family to allergy-inducing mold, address this problem as soon as possible. 

A clogged air filter can harbor mold, so eliminating the smell could be as straightforward as swapping out filter. If that doesn’t work, the AC evaporator coil mounted near the furnace could be the culprit. This component accumulates condensation, which will sometimes induce 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 requesting air duct cleaning. This service eliminates hidden mold, regardless of where it’s growing in your ventilation. 

The Furnace Smells Like Spoiled Eggs 

This is one of the most worrisome furnace smells since it frequently implies a gas leak. The utility company adds a useful substance known as mercaptan to the natural gas supply to make leaks easier to notice. 

If you detect a rotten egg smell close to your furnace or out of your ductwork, shut off the heater immediately. If you remember where the main gas supply valve is located, shut that off also. Then, evacuate your home and contact 911, followed by your gas company. Don’t reenter the house until a professional confirms it’s safe. 

The Furnace Has a Sour Stench 

If you discover a sour smell that stings your nose while close to64} the furnace, this may mean the heat exchanger has cracked. This vital component houses68} combustion fumes, including carbon monoxide, so cracks may pump unsafe levels of CO gas into your home. 

Carbon monoxide poisoning can be fatal, so shut off your furnace right away if you notice a sour odor. Then, call 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 functional CO detectors on every floor of your home. 

The Furnace Smells Dusty 

When you fire up the furnace for the first time each fall, you can expect a dusty odor to show up 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 dissipates within one day, you shouldn’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 safely out of your home. A smoky smell could mean the flue is backed up, and now fumes are flowing back into your home. The odor may permeate the entire house, endangering your family’s health if you ignore it. So switch off the furnace and get in touch with a professional straightaway to schedule a repair. 

The Furnace Smell Resembles Burning Plastic 

Overheating and melting electrical components are the most plausible reason for a burning plastic smell to come from your furnace. A failing fan motor is another possibility. If you don’t correct the problem, an electrical fire could 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 troubleshooting and repairing this weird furnace smell. 

The Furnace Has an Oily Smell 

If you use an oil furnace, you could detect this odor whenever the oil filter becomes clogged. Try replacing it to see if that addresses the problem. If the smell persists for more than a day after carrying out this step, it could indicate an oil leak. You should get help from an HVAC expert to fix this problem. 

The Furnace Smell Resembles Sewer Odors 

Sewer gas smells very similar to spoiled eggs, so first rule out the likelihood of a natural gas leak. If that’s not the source, your home’s sewer lines could have an issue, such as a dry trap or sewer leak. Flush water down all your drains, including the basement floor drain, to replenish dry sewer traps. If the smell persists, go ahead and contact a sewer line repair company. 

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

When in doubt, call an HVAC technician to assess and repair your furnace. At Service Experts Heating, Air Conditioning & Plumbing, we perform comprehensive diagnostic services to pinpoint the problem before repairs begin. Then, we suggest the most viable, cost-effective repairs, as well as 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.