Why Your Furnace Has a Strange Smell

As the weather cools down and you swap from cooling to heating your home, some homeowners are worried about weird furnace smells in the air. Find out what the most common furnace smells could suggest and how concerned you should be about them.

The Furnace Smells Musty

Musty furnace odors generally imply mold growth someplace in the HVAC system. To avoid exposing your family to allergy-inducing mold, handle this problem as quickly as possible.

A damp air filter can encourage mold, so eliminating the smell could be as straightforward as getting a new filter. If that doesn't help, the AC evaporator coil fastened near the furnace may be the root of the problem. This component gathers condensation, which will sometimes induce mold growth. You’ll need a professional’s help to check and clean the evaporator coil. When the problem still won't go away, consider requesting air duct cleaning. This service eliminates hidden mold, regardless of where it’s growing in your ventilation.

The Furnace Smells Like Spoiled Eggs

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

If you detect a rotten egg smell around your furnace or out of your ductwork, switch off the heater immediately. If you remember where the main gas supply valve is placed, shut that off also. Then, get out of the house and contact 911, followed by 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 notice a sour smell that stings your nose while standing close to the furnace, this might mean the heat exchanger cracked open. This essential component safely contains combustion fumes, including carbon monoxide, so a crack may spew unsafe levels of CO gas into your home.

Carbon monoxide poisoning could be lethal, so shut off your furnace right away if you detect a sour odor. Then, call an HVAC professional for an inspection. Consider replacing your furnace if a cracked heat exchanger is responsible. For your continued safety going forward, see to it that you have working CO detectors on each floor of your home.

The Furnace Smells Dusty

When you start 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 one 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 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 contact a professional right away to schedule a repair.

The Furnace Smells Like Burning Plastic

Overheating and burned electrical components are the most plausible reason for a burning plastic smell to make an appearance. A malfunctioning fan motor is another common cause. If you don’t correct the problem, an electrical fire might start, or your furnace could end up with irreparable damage. Disable the heating system as soon as possible and call an HVAC technician for help diagnosing and repairing this weird furnace smell.

The Furnace Has an Oily Smell

If you use an oil furnace, you may notice this odor if the oil filter becomes clogged. Try replacing it to determine if that addresses the problem. If the smell lingers for more than a day after carrying out this step, it could indicate an oil leak. You'll be better off with help from an HVAC expert to fix this problem.

The Furnace Smells Like Sewer Odors

Sewer gas smells quite similar to rotting eggs, so first eliminate the likelihood of a natural gas leak. If that’s not the issue, the sewer lines may have an issue, such as a dry trap or sewer leak. Flush water down your own drains, including the basement floor drain, to fill dried-out sewer traps. If the smell persists, you’ll need to contact a sewer line repair company.

Contact Strogen's Service Experts for Furnace Repair

If you're still uncertain, get in touch with an HVAC technician to assess and repair your furnace. At Strogen's Service Experts, we deliver comprehensive diagnostic services to determine the problem before the work begins. Then, we suggest the most viable, cost-effective repairs, alongside an up-front estimate for each option. 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 ask questions about why your furnace smells bad or to request furnace repair near you, please contact your local Strogen's Service Experts office today.

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