Why Your Furnace Has a Strange Smell

As the weather gets colder and you transition from cooling to heating your home, some homeowners are worried about unusual furnace smells filling the air. Find out what the most common furnace smells mean and how proactive you should be about each one.

The Furnace Smells Musty

Musty furnace smells almost always suggest mold growth somewhere in the HVAC system. To avoid subjecting your family to mold and mildew spores, address this problem as soon as possible.

A clogged air filter can harbor mold, so eliminating the smell can be as straightforward as swapping out filter. If that doesn't help, the AC evaporator coil fastened near the furnace may be to blame. This component gathers condensation, which could trigger 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, start thinking about scheduling air duct cleaning. This service removes hidden mold, regardless of where it’s growing in your ductwork.

The Furnace Smells Like Rotten Eggs

This is one of the most nerve-wracking furnace smells due to the fact that it probably suggests a gas leak. The utility company includes a special substance called 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, shut that off as well. Then, evacuate your home and call 911, as well as your gas company. Don’t enter the house until a professional confirms it’s safe.

The Furnace Has a Sour Stench

If you detect a sour smell that stings your nose while standing close to the furnace, this could mean the heat exchanger is cracked. This essential component safely contains combustion fumes, such as carbon monoxide, so cracks could spew unsafe levels of CO gas into your home.

Carbon monoxide poisoning could be deadly, so turn 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 family's safety going forward, make sure 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 probably expect a dusty odor to fill the house 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 goes away within 24 hours, you don'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 up and out of your home. 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, risking your family’s health if you ignore it. So shut down the furnace and call a professional as soon as you can to arrange for repair.

The Furnace Smells Like Burning Plastic

Overheating and burned electrical components are the most common reason for a burning plastic smell to come from your furnace. A malfunctioning fan motor is another common cause. If you don’t tackle the problem, an electrical fire could start, or your furnace could end up with irreparable damage. Disable the heating system right away and contact an HVAC technician for help troubleshooting and repairing this unpleasant furnace smell.

The Furnace Has an Oily Smell

If you own an oil furnace, you might pick up on this smell if the oil filter becomes blocked up. Try replacing it to determine if that fixes the problem. If the smell lingers for more than a day after completing this step, it could indicate an oil leak. You should get help from an HVAC expert to address this problem.

The Furnace Smells Like Sewer Odors

Sewer gas smells quite similar to rotten eggs, so first determine the potential for a natural gas leak. If that’s not the problem, the sewer lines could have an issue, such as a dry trap or sewer leak. Pour water down the drains, including the basement floor drain, to replenish dry sewer traps. If the smell persists, go ahead and contact a sewer line repair company.

Contact Eveready Service Experts for Furnace Repair

When in doubt, call an HVAC technician to assess and repair your furnace. At Eveready Service Experts , we deliver thorough diagnostic services to pinpoint the problem before we figure out the best solution. Then, we encourage the most viable, cost-effective repairs, along with 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 Eveready Service Experts office today.

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