Why Your Furnace Has a Strange Smell

As the weather cools down 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 mean and how concerned you should be about each one. 

The Furnace Smells Musty 

Musty furnace odors almost always imply mold growth somewhere 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 might be as easy as replacing the filter. If that doesn’t work, the AC evaporator coil placed near the furnace could be to blame. This component gathers condensation, which could trigger mold growth. You’ll want a professional’s help to check and clean the evaporator coil. When all else fails, consider scheduling air duct cleaning. This service eliminates hidden mold, no matter where it’s growing in your ductwork. 

The Furnace Smells Like Rotten Eggs 

This is one of the most worrisome furnace smells due to the fact that it most likely implies a gas leak. The utility company adds a useful substance known as mercaptan to the natural gas supply to make leaks more easily detected. 

If you notice a rotten egg smell close to your furnace or coming from your vents, 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, followed by your gas company. Don’t enter 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 could mean the heat exchanger cracked open. This vital component houses68} combustion fumes, like carbon monoxide, so a crack could pump unsafe levels of CO gas into your home. 

Carbon monoxide poisoning could be lethal, so shut off your furnace right away if you notice a sour odor. Then, contact an HVAC professional for an inspection. Consider replacing your furnace if a cracked heat exchanger is to blame. For your continued safety going forward, make sure you have reliable CO detectors on every floor of your home. 

The Furnace Smells Dusty 

When you fire up the furnace for the first time every fall, you probably expect a dusty odor to fill the house for a little while. 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 a 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 to the exterior. A smoky smell can mean the flue is blocked, and now fumes are settling back into your home. The odor may permeate the entire house, risking your family’s health if you ignore it. So shut down the furnace and get in touch with a professional right away to schedule a repair. 

The Furnace Smell Resembles Burning Plastic 

Overheating and melting electrical components are the most likely reason for a burning plastic smell to make an appearance. A failing fan motor is another possibility. If you don’t address the problem, an electrical fire could start, or your furnace could experience irreparable damage. Turn off the heating system immediately and call an HVAC technician for help diagnosing and repairing this unpleasant furnace smell. 

The Furnace Has an Oily Smell 

If you have an oil furnace, you may pick up on this odor when the oil filter becomes clogged. Try replacing it to see if that fixes the problem. If the smell lingers for more than a day after taking care of this step, it could imply an oil leak. You’ll need help from an HVAC expert to address this problem. 

The Furnace Reeks of Sewer Odors 

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

Contact Teays Valley Service Experts for Furnace Repair 

When in doubt, contact an HVAC technician to check and repair your furnace. At Teays Valley Service Experts, we perform comprehensive diagnostic services to pinpoint the problem before repairs begin. Then, we encourage the most viable, cost-effective repairs, alongside an up-front estimate for all options. Our ACE-certified technicians can resolve just about any heating problem, 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 Teays Valley Service Experts office today.