Why Your Furnace Has a Strange Smell

As the weather turns cold and you swap from cooling to heating your home, some homeowners are worried about weird furnace smells filling the air. Learn about what the most common furnace smells could mean and how proactive you should be about each one.

The Furnace Smells Musty

Musty furnace smells almost always imply mold growth hiding in the HVAC system. To avoid exposing your family to allergy-inducing mold, address this problem right away.

A damp air filter can encourage mold, so wiping out the smell can be as simple as getting a new filter. If that doesn’t work, the AC evaporator coil mounted near the furnace may be the root of the problem. This component gathers condensation, which will sometimes trigger mold growth. You'll be better off with a professional’s help to inspect and clean the evaporator coil. When all else fails, start thinking about investing in air duct cleaning. This service cleans away hidden mold, regardless of where it's hiding in your ventilation.

The Furnace Smells Like Spoiled Eggs

This is one of the most nerve-wracking furnace smells due to the fact that it probably implies a gas leak. The utility company puts in a useful substance known as mercaptan to the natural gas supply to make leaks more easily detected.

If you recognize a rotten egg smell close to your furnace or coming from your air ducts, shut down the heater immediately. If you can find where the main gas supply valve is placed, shut that off as well. Then, get out of the house and dial 911, followed by your gas company. Don’t enter the house until a professional confirms it’s safe.

The Furnace Has a Sour Stench

If you discover a sour smell that stings your nose while standing near the furnace, this might mean the heat exchanger cracked open. This essential component safely contains combustion fumes, including carbon monoxide, so cracks may spew unsafe levels of CO gas into your home.

Carbon monoxide poisoning can be deadly, so switch off your furnace immediately if you notice a sour odor. Then, reach out to an HVAC professional for an inspection. Consider replacing your furnace if a cracked heat exchanger is responsible. For your family's safety going forward, ensure you have reliable CO detectors on every floor of your home.

The Furnace Smells Dusty

When you turn on the furnace for the first time every fall, you can expect a dusty odor to show up for a little while. 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 goes away 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 up and out of your home. A smoky smell could mean the flue is backed up, and now fumes are flowing back into your home. The odor can reach through the entire house, risking 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 plausible reason for a burning plastic smell to make an appearance. A faulty fan motor is another common cause. If you don’t address the problem, an electrical fire might start, or your furnace could suffer from irreparable damage. Shut off the heating system right away and call an HVAC technician for help diagnosing and repairing this weird furnace smell.

The Furnace Has an Oily Smell

If you have an oil furnace, you could pick up on this smell whenever the oil filter becomes clogged. Try replacing it to find out if that fixes the problem. If the smell persists for more than a day after carrying out this step, it could indicate an oil leak. You should get help from an HVAC professional to address this problem.

The Furnace Reeks of Sewer Odors

Sewer gas smells pretty similar to spoiled eggs, so first determine the potential for a natural gas leak. If that’s not the source, the sewer lines might have an issue, such as a dry trap or sewer leak. Pour water down your own drains, including the basement floor drain, to fill dried-up sewer traps. If the smell sticks around, you should contact a sewer line repair company.

Contact Service Experts Heating & Air Conditioning for Furnace Repair

If you're still uncertain, contact an HVAC technician to examine and repair your furnace. At Service Experts Heating & Air Conditioning, we deliver comprehensive diagnostic services to identify the problem before we figure out the best solution. 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 malfunction, and we back our work with a 100% satisfaction guarantee for one year. To learn more about why your furnace smells bad or to request furnace repair near you, please contact your local Service Experts Heating & Air Conditioning office today.

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