Why Your Furnace Has a Strange Smell

As the weather gets colder and you swap from cooling to heating your home, you may be worried about weird furnace smells filling the air. Find out what the most common furnace smells mean and how worried you should be about each one. 

The Furnace Smells Musty 

Musty furnace smells almost always imply mold growth someplace in the HVAC system. To avoid subjecting your family to these microorganisms, address this problem as soon as possible. 

A damp air filter can harbor mold, so eliminating the smell could be as easy as replacing the filter. If that doesn’t work, the AC evaporator coil fastened near the furnace may be the root of the problem. This component accumulates condensation, which could stimulate mold growth. You’ll be better off with a professional’s help to examine and clean the evaporator coil. When this still doesn’t help, consider requesting air duct cleaning. This service eliminates hidden mold, regardless of where it’s hiding 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 probably indicates a gas leak. The utility company includes a particular substance known as mercaptan to the natural gas supply to make leaks easier to detect. 

If you recognize a rotten egg smell near your furnace or coming from your vents, shut down the heater right away. If you know where the main gas supply valve is placed, shut that off as well. Then, evacuate your home and contact 911, as well as your gas company. Don’t reenter the house until a professional tells you 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 cracked open. This vital component contains68} combustion fumes, such as carbon monoxide, so a crack could pump unsafe levels of CO gas into your home. 

Carbon monoxide poisoning could be fatal, so switch off your furnace right away if you recognize a sour odor. Then, reach out to 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, ensure you have functional 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 can expect a dusty odor to appear for a few minutes. This is the smell of six months’ worth of dust burning away as the furnace wakes from its summer slumber. As long as the smell dissipates 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 up and 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, risking your family’s health if you let it continue. So switch off the furnace and call a professional right away to request furnace repair. 

The Furnace Smells Like Burning Plastic 

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

The Furnace Has an Oily Smell 

If you use an oil furnace, you might pick up on this smell whenever the oil filter becomes clogged. Try replacing it to see if that resolves the problem. If the smell persists for more than one day 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 Smells Like Sewer Odors 

Sewer gas smells pretty similar to rotting eggs, so first determine the possibility of a natural gas leak. If that’s not the problem, your home’s sewer lines may have an issue, for example a dry trap or sewer leak. Pour water down all your drains, including the basement floor drain, to refresh dried-up sewer traps. If the smell sticks around, go ahead and contact a sewer line repair company. 

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

If you’re still unsure, call an HVAC technician to assess and repair your furnace. At Service Experts Heating, Air Conditioning & Plumbing, we deliver comprehensive diagnostic services to pinpoint the problem before the work begins. Then, we suggest the most viable, cost-effective repairs, alongside an up-front estimate for each option. Our ACE-certified technicians can resolve just about any heating problem, 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.