Why Your Furnace Has a Strange Smell

As the weather turns cold and you transition from cooling to heating your home, you might be worried about unusual 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 indicate mold growth somewhere in the HVAC system. To avoid subjecting your family to allergy-inducing mold, handle 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 could be to blame. This component collects condensation, which will sometimes trigger mold growth. You’ll want a professional’s help to examine and clean the evaporator coil. When all else fails, consider investing in air duct cleaning. This service removes hidden mold, no matter where it’s growing in your ventilation. 

The Furnace Smells Like Rotten Eggs 

This is one of the most nerve-wracking furnace smells because it most likely indicates a gas leak. The utility company adds a useful substance known as mercaptan to the natural gas supply to make leaks easier to detect. 

If you detect a rotten egg smell close to your furnace or coming from your vents, shut off the heater right away. If you know where the main gas supply valve is, shut that off as well. Then, get out of the house and call 911, followed by 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 detect a sour smell that stings your nose while close to64} the furnace, this could mean the heat exchanger has cracked. This vital component safely contains68} combustion fumes, including carbon monoxide, so cracks could pump unsafe levels of CO gas into your home. 

Carbon monoxide poisoning can be lethal, so shut off your furnace right away if you recognize 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 functional CO detectors on all floors 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 appear for a few minutes. 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 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 backdrafting into your home. The odor may permeate the entire house, endangering your family’s health if you let it continue. So shut down the furnace and get in touch with a professional right away to schedule a repair. 

The Furnace Smells Like It’s Burning Plastic 

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

The Furnace Has an Oily Smell 

If you own an oil furnace, you may notice 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 carrying out this step, it could indicate an oil leak. You’ll need help from an HVAC expert to handle this problem. 

The Furnace Reeks of Sewer Odors 

Sewer gas smells quite similar to rotten eggs, so first eliminate the potential for 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. Flush water down all your drains, including the basement floor drain, to fill dried-up sewer traps. If the smell lingers, you’ll need to contact a sewer line repair company. 

Contact Calverley Service Experts for Furnace Repair 

When in doubt, get in touch with an HVAC technician to examine and repair your furnace. At Calverley Service Experts, we deliver complete diagnostic services to pinpoint the problem before repairs begin. Then, we recommend the most viable, cost-effective repairs, as well as 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. For details about why your furnace smells bad or to request furnace repair near you, please contact your local Calverley Service Experts office today.