Why Your Furnace Has a Strange Smell

As the weather gets colder and you swap from cooling to heating your home, some homeowners are worried about weird furnace smells floating in the air. Learn about what the most common furnace smells could suggest and how concerned you should be about each one.

The Furnace Smells Musty

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

A clogged air filter can encourage mold, so eliminating the smell could be as easy as getting a new filter. If that doesn’t work, the AC evaporator coil fastened near the furnace could be the culprit. This component collects condensation, which will sometimes stimulate mold growth. You'll be better off with a professional’s help to examine and clean the evaporator coil. When all else fails, take a look at scheduling air duct cleaning. This service eliminates hidden mold, regardless of where it’s growing in your ventilation.

The Furnace Smells Like Rotten Eggs

This is one of the most nerve-wracking furnace smells since it probably indicates a gas leak. The utility company includes a useful substance known as mercaptan to the natural gas supply to make leaks more easily detected.

If you detect a rotten egg smell close to your furnace or coming from your air ducts, switch off the heater right away. If you can find where the main gas supply valve is located, shut that off too. Then, leave 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 near the furnace, this may mean the heat exchanger has cracked. This vital component safely contains combustion fumes, including carbon monoxide, so a cracked heat exchanger may pump unsafe levels of CO gas into your home.

Carbon monoxide poisoning could be lethal, 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 health and safety going forward, make sure you have working 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 should 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 disperses within a day, 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 safely out of your home. A smoky smell could mean the flue is clogged, and now fumes are backdrafting into your home. The odor may permeate the entire house, jeopardizing your family’s health if you ignore it. So turn off the furnace and get in touch with a professional right away to request furnace repair.

The Furnace Smell Resembles Burning Plastic

Overheating and melting electrical components are the most common reason for a burning plastic smell to come from your furnace. A malfunctioning fan motor is another possibility. If you don’t tackle the problem, an electrical fire may start, or your furnace could suffer from irreparable damage. Shut off the heating system as soon as possible and call an HVAC technician for help troubleshooting and repairing this unusual furnace smell.

The Furnace Has an Oily Smell

If you have an oil furnace, you might pick up on this smell whenever the oil filter becomes clogged. Try replacing it to find out if that resolves the problem. If the smell persists for more than one day after taking care of this step, it may 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 spoiled eggs, so first rule out the possibility of a natural gas leak. If that’s not the problem, 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 fill dry sewer traps. If the smell persists, go ahead and contact a sewer line repair company.

Contact Falso Service Experts for Furnace Repair

If you're still unsure, get in touch with an HVAC technician to assess and repair your furnace. At Falso Service Experts, we offer comprehensive diagnostic services to determine the problem before we figure out the best solution. Then, we recommend the most viable, cost-effective repairs, as well as an up-front estimate for all options. Our ACE-certified technicians can handle just about any heating repair, 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 Falso Service Experts office today.

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