Why Your Furnace Has a Strange Smell

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

The Furnace Smells Musty 

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

A clogged air filter can lead to mold, so getting rid of the smell can be as easy as swapping out filter. If that doesn’t work, the AC evaporator coil placed near the furnace may be the culprit. This component accumulates condensation, which can stimulate 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, start thinking about investing in air duct cleaning. This service cleans away hidden mold, regardless of where it’s hiding in your ductwork. 

The Furnace Smells Like Spoiled Eggs 

This is one of the most worrisome furnace smells since it most likely implies a gas leak. The utility company puts in a useful substance called mercaptan to the natural gas supply to make leaks easier to detect. 

If you recognize a rotten egg smell near your furnace or originating from your ductwork, switch off the heater immediately. If you know where the main gas supply valve is placed, shut that off too. 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 tells you 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 could mean the heat exchanger is cracked. This important component contains68} combustion fumes, including carbon monoxide, so a crack might allow unsafe levels of CO gas into your home. 

Carbon monoxide poisoning has the potential to be deadly, so turn off your furnace immediately 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 health and safety going forward, make sure you have working CO detectors on each floor of your home. 

The Furnace Smells Dusty 

When you fire up the furnace for the first time every fall, you should expect a dusty odor to fill the house for a brief moment. 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 goes away 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 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 may permeate the entire house, endangering your family’s health if you let it continue. So switch off the furnace and call a professional right away to schedule a repair. 

The Furnace Smells Like Burning Plastic 

Overheating and melted electrical components are the most common reason for a burning plastic smell to make an appearance. A malfunctioning fan motor is another possibility. If you don’t address the problem, an electrical fire might start, or your furnace could suffer from irreparable damage. Shut off the heating system right away and contact an HVAC technician for help identifying and repairing this unpleasant furnace smell. 

The Furnace Has an Oily Smell 

If you use an oil furnace, you could notice this odor when the oil filter becomes clogged. Try replacing it to determine if that resolves the problem. If the smell persists for more than 24 hours after taking care of this step, it may indicate an oil leak. You’ll need help from an HVAC professional to handle this problem. 

The Furnace Smell Resembles Sewer Odors 

Sewer gas smells very similar to rotting eggs, so first determine the potential for a natural gas leak. If that’s not the source, your home’s sewer lines might have an issue, like a dry trap or sewer leak. Pour water down your own drains, including the basement floor drain, to refresh dried-out sewer traps. If the smell sticks around, you should contact a sewer line repair company. 

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

If you’re still unsure, contact an HVAC technician to examine and repair your furnace. At Service Experts Heating, Air Conditioning & Plumbing, we deliver comprehensive diagnostic services to pinpoint the problem before repairs begin. Then, we suggest the most viable, cost-effective repairs, alongside an up-front estimate for all options. 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.