Why Your Furnace Has a Strange Smell

As the weather turns cold and you switch from cooling to heating your home, you might be worried about weird furnace smells floating in the air. Learn about what the most common furnace smells mean and how proactive you should be about them.

The Furnace Smells Musty

Musty furnace smells generally imply mold growth hiding in the HVAC system. To avoid subjecting your family to allergy-inducing mold, tackle this problem right away.

A clogged air filter can lead to mold, so eliminating the smell could be as straightforward as swapping out filter. If that doesn't help, the AC evaporator coil fastened near the furnace could be the culprit. This component accumulates 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 the problem still won't go away, take a look at requesting air duct cleaning. This service removes hidden mold, no matter where it’s growing in your ductwork.

The Furnace Smells Like Rotten Eggs

This is one of the most nerve-wracking furnace smells because it most likely implies a gas leak. The utility company adds a useful substance called mercaptan to the natural gas supply to make leaks easier to notice.

If you detect a rotten egg smell around your furnace or coming from your air ducts, shut off the heater straightaway. If you can find where the main gas supply valve is, shut that off also. Then, evacuate your home and dial 911, as well as your gas company. Don’t go back in 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 could mean the heat exchanger cracked open. This important component 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 deadly, so switch off your furnace right away if you recognize a sour odor. Then, call an HVAC professional for an inspection. Consider replacing your furnace if a cracked heat exchanger is responsible. For your health and safety going forward, ensure you have reliable CO detectors on every floor of your home.

The Furnace Smells Dusty

When you fire up the furnace for the first time after a while, you should expect a dusty odor to show up for a few minutes. This is the smell of six months’ worth of dust burning up as the furnace wakes up. 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 will sometimes mean the flue is blocked, 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 straightaway to schedule a repair.

The Furnace Smell Resembles Burning Plastic

Overheating and melting electrical components are the most plausible reason for a burning plastic smell to come from your furnace. A malfunctioning fan motor is another common cause. If you don’t correct the problem, an electrical fire could start, or your furnace could end up with irreparable damage. Shut off the heating system immediately and contact an HVAC technician for help identifying and repairing this weird furnace smell.

The Furnace Has an Oily Smell

If you use an oil furnace, you may detect this stench whenever the oil filter becomes blocked up. Try replacing it to find out if that resolves the problem. If the smell persists for more than a day after taking care of this step, it could suggest an oil leak. You'll be better off with help from an HVAC professional to handle this problem.

The Furnace Smells Like Sewer Odors

Sewer gas smells pretty similar to spoiled eggs, so first eliminate the possibility of a natural gas leak. If that’s not the source, your home's sewer lines could have an issue, like a dry trap or sewer leak. Pour water down your own drains, including the basement floor drain, to replenish dry sewer traps. If the smell persists, you’ll need to contact a sewer line repair company.

Contact Peachtree Service Experts for Furnace Repair

If you're still uncertain, get in touch with an HVAC technician to check and repair your furnace. At Peachtree Service Experts, we offer comprehensive diagnostic services to pinpoint the problem before repairs begin. Then, we suggest the most viable, cost-effective repairs, alongside an up-front estimate for all options. Our ACE-certified technicians can handle 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 Peachtree Service Experts office today.

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