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 floating in the air. Learn what the most common furnace smells mean and how worried you should be about them.

The Furnace Smells Musty

Musty furnace smells generally suggest mold growth someplace in the HVAC system. To avoid exposing your family to mold and mildew spores, handle this problem as soon as possible.

A clogged air filter can lead to mold, so getting rid of the smell can be as straightforward as getting a new filter. If that doesn’t work, the AC evaporator coil fastened near the furnace might be the root of the problem. This component accumulates condensation, which could induce mold growth. You'll be better off with a professional’s help to examine and clean the evaporator coil. When all else fails, consider scheduling air duct cleaning. This service cleans away hidden mold, regardless of where it's hiding 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 implies a gas leak. The utility company adds a particular substance called mercaptan to the natural gas supply to make leaks easier to detect.

If you recognize a rotten egg smell near your furnace or coming from your air ducts, shut down the heater immediately. If you remember where the main gas supply valve is placed, shut that off as well. 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 discover a sour smell that stings your nose while standing close to the furnace, this could mean the heat exchanger is cracked. This important component safely contains combustion fumes, including carbon monoxide, so a crack may pump unsafe levels of CO gas into your home.

Carbon monoxide poisoning could be deadly, so switch off your furnace as soon as possible if you detect a sour odor. Then, reach out to an HVAC professional for an inspection. Consider replacing your furnace if a cracked heat exchanger is the culprit. For your continued safety going forward, make sure you have reliable CO detectors on each floor of your home.

The Furnace Smells Dusty

When you turn on the furnace for the first time every fall, you probably expect a dusty odor to show up for a brief moment. This is the smell of six months’ worth of dust burning off as the furnace wakes up. As long as the smell disperses within one 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 safely out of your home. A smoky smell can mean the flue is blocked, and now fumes are backdrafting into your home. The odor can reach through the entire house, risking your family’s health if you ignore it. So turn off the furnace and contact a professional right away to schedule a 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 also possible. If you don’t address the problem, an electrical fire may start, or your furnace could experience irreparable damage. Shut off the heating system as soon as possible and call an HVAC technician for help troubleshooting and repairing this unpleasant furnace smell.

The Furnace Has an Oily Smell

If you use an oil furnace, you could detect this smell if the oil filter becomes blocked up. Try replacing it to see if that addresses the problem. If the smell persists for more than 24 hours after completing this step, it might suggest an oil leak. You'll be better off with help from an HVAC expert to address this problem.

The Furnace Smell Resembles Sewer Odors

Sewer gas smells pretty similar to rotten eggs, so first rule out the likelihood of 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 the drains, including the basement floor drain, to refresh dried-out sewer traps. If the smell lingers, you should contact a sewer line repair company.

Contact Rolf Griffin Service Experts for Furnace Repair

If you're still unsure, call an HVAC technician to check and repair your furnace. At Rolf Griffin Service Experts , we deliver complete diagnostic services to pinpoint the problem before the work begins. Then, we recommend the most viable, cost-effective repairs, along with an up-front estimate for every option. Our ACE-certified technicians can resolve just about any heating repair, 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 Rolf Griffin Service Experts office today.

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