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 in the air. Learn what the most common furnace smells could suggest and how worried you should be about each one.

The Furnace Smells Musty

Musty furnace odors usually indicate mold growth somewhere in the HVAC system. To avoid subjecting your family to allergy-inducing mold, address this problem as soon as possible.

A damp air filter can encourage mold, so wiping out the smell might be as straightforward as swapping out filter. If that doesn't help, the AC evaporator coil fastened near the furnace could be to blame. This component collects condensation, which can stimulate mold growth. You'll want a professional’s help to examine and clean the evaporator coil. When the problem still won't go away, take a look at requesting air duct cleaning. This service cleans away hidden mold, no matter where it's hiding in your ductwork.

The Furnace Smells Like Rotting Eggs

This is one of the most nerve-wracking furnace smells due to the fact that it most likely suggests a gas leak. The utility company includes a useful substance called mercaptan to the natural gas supply to make leaks easier to notice.

If you recognize a rotten egg smell close to your furnace or originating from your vents, switch off the heater straightaway. If you can find where the main gas supply valve is, shut that off too. Then, leave the house and call 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 notice a sour smell that stings your nose while standing near the furnace, this might mean the heat exchanger has cracked. This vital component safely contains combustion fumes, like carbon monoxide, so a cracked heat exchanger might pump unsafe levels of CO gas into your home.

Carbon monoxide poisoning can be fatal, so switch off your furnace immediately if you detect a sour odor. Then, call an HVAC professional for an inspection. Consider replacing your furnace if a cracked heat exchanger is the culprit. For your family's safety going forward, make sure you have working CO detectors on all floors of your home.

The Furnace Smells Dusty

When you turn on the furnace for the first time after a while, you can expect a dusty odor to fill the house for a little while. This is the smell of six months’ worth of dust burning up as the furnace wakes from its summer slumber. As long as the smell goes away within 24 hours, 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 to the exterior. A smoky smell could mean the flue is clogged, and now fumes are flowing back into your home. The odor can reach through the entire house, jeopardizing your family’s health if you let it continue. So turn off the furnace and call a professional right away to request furnace repair.

The Furnace Smells Like It's Burning Plastic

Overheating and burned electrical components are the most likely reason for a burning plastic smell to come from your furnace. A faulty fan motor is another common cause. If you don’t correct the problem, an electrical fire could start, or your furnace could experience irreparable damage. Disable the heating system right away and call an HVAC technician for help identifying and repairing this weird furnace smell.

The Furnace Has an Oily Smell

If you have an oil furnace, you might detect this smell if the oil filter becomes blocked up. Try replacing it to see if that resolves the problem. If the smell persists for more than 24 hours after carrying out this step, it could imply an oil leak. You’ll need help from an HVAC expert to handle this problem.

The Furnace Reeks of Sewer Odors

Sewer gas smells pretty similar to rotting eggs, so first determine the potential for a natural gas leak. If that’s not the issue, your sewer lines may have an issue, like a dry trap or sewer leak. Try pouring water down your own drains, including the basement floor drain, to fill dry sewer traps. If the smell lingers, you should contact a sewer line repair company.

Contact BW/Cook Service Experts for Furnace Repair

When in doubt, get in touch with an HVAC technician to examine and repair your furnace. At BW/Cook Service Experts, we deliver thorough diagnostic services to pinpoint the problem before repairs begin. Then, we recommend the most viable, cost-effective repairs, alongside an up-front estimate for every option. Our ACE-certified technicians can manage just about any heating malfunction, and we back our work with a 100% satisfaction guarantee for one year. To ask questions about why your furnace smells bad or to request furnace repair near you, please contact your local BW/Cook Service Experts office today.

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