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. Learn what the most common furnace smells could mean and how concerned you should be about them. 

The Furnace Smells Musty 

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

A clogged air filter can harbor mold, so getting rid of the smell might be as easy as swapping out filter. If that doesn’t help, the AC evaporator coil placed near the furnace could be the culprit. This component gathers condensation, which will sometimes trigger mold growth. You’ll need a professional’s help to examine and clean the evaporator coil. When this still doesn’t help, take a look at investing in air duct cleaning. This service eliminates hidden mold, no matter where it’s growing in your air ducts. 

The Furnace Smells Like Spoiled Eggs 

This is one of the most worrisome furnace smells due to the fact that it probably suggests a gas leak. The utility company includes a special substance known as mercaptan to the natural gas supply to make leaks easier to detect. 

If you notice a rotten egg smell near your furnace or coming from your vents, shut off the heater right away. If you can find where the main gas supply valve is placed, shut that off also. Then, evacuate your home and dial 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 notice a sour smell that stings your nose while standing close to64} the furnace, this might mean the heat exchanger cracked open. This essential component contains68} combustion fumes, including carbon monoxide, so a cracked heat exchanger could allow unsafe levels of CO gas into your home. 

Carbon monoxide poisoning could be fatal, so switch 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 the culprit. For your health and safety going forward, see to it that 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 disperses 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 can mean the flue is blocked, and now fumes are backdrafting into your home. The odor may permeate the entire house, jeopardizing your family’s health if you ignore it. So switch off the furnace and call a professional straightaway to arrange for repair. 

The Furnace Smells Like Burning Plastic 

Overheating and melted electrical components are the most plausible reason for a burning plastic smell to come from your furnace. A faulty fan motor is another common cause. If you don’t address the problem, an electrical fire may 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 unusual furnace smell. 

The Furnace Has an Oily Smell 

If you have an oil furnace, you might pick up on this smell if the oil filter becomes clogged. Try replacing it to find out if that addresses the problem. If the smell lingers for more than a day after taking care of this step, it could indicate an oil leak. You should get help from an HVAC professional to fix this problem. 

The Furnace Smell Resembles Sewer Odors 

Sewer gas smells quite similar to rotten eggs, so first rule out the possibility of a natural gas leak. If that’s not the issue, your sewer lines could have an issue, like a dry trap or sewer leak. Try pouring water down the drains, including the basement floor drain, to refresh dry sewer traps. If the smell persists, you should contact a sewer line repair company. 

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

When in doubt, call an HVAC technician to check and repair your furnace. At Service Experts Heating, Air Conditioning & Plumbing, we deliver thorough diagnostic services to determine the problem before the work begins. 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. For details 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.