Why Your Furnace Has a Strange Smell

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

The Furnace Smells Musty

Musty furnace smells usually indicate mold growth somewhere in the HVAC system. To avoid exposing your family to allergy-inducing mold, tackle this problem as quickly as possible.

A clogged air filter can harbor mold, so eliminating the smell might be as straightforward as swapping out filter. If that doesn’t work, the AC evaporator coil mounted near the furnace could be to blame. This component accumulates condensation, which will sometimes trigger mold growth. You’ll need a professional’s help to examine and clean the evaporator coil. When the problem still won't go away, start thinking about requesting air duct cleaning. This service eliminates hidden mold, regardless of where it’s growing in your ventilation.

The Furnace Smells Like Rotting Eggs

This is one of the most worrisome furnace smells because it probably implies a gas leak. The utility company puts in a particular substance known as mercaptan to the natural gas supply to make leaks easier to detect.

If you recognize a rotten egg smell near your furnace or originating from your ductwork, shut off the heater straightaway. If you know where the main gas supply valve is, shut that off too. Then, get out of the house and contact 911, followed by your gas company. Don’t reenter the house until a professional tells you it’s safe.

The Furnace Has a Sour Stench

If you detect a sour smell that stings your nose while standing close to the furnace, this may mean the heat exchanger has cracked. This vital component safely contains combustion fumes, such as carbon monoxide, so cracks might pump unsafe levels of CO gas into your home.

Carbon monoxide poisoning could be lethal, so turn off your furnace as soon as possible if you recognize 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, 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 after a while, you can 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 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 to the exterior. A smoky smell can mean the flue is clogged, and now fumes are settling back into your home. The odor might eventually reach the entire house, jeopardizing your family’s health if you ignore it. So switch off the furnace and call a professional straightaway to arrange for repair.

The Furnace Smells Like Burning Plastic

Overheating and melting electrical components are the most common reason for a burning plastic smell to come from your furnace. A faulty fan motor is another possibility. If you don’t address the problem, an electrical fire could start, or your furnace could experience irreparable damage. Disable the heating system right away and contact an HVAC technician for help diagnosing and repairing this unpleasant furnace smell.

The Furnace Has an Oily Smell

If you own an oil furnace, you might detect this odor whenever the oil filter becomes clogged. Try replacing it to see if that fixes the problem. If the smell remains for more than a day after taking care of this step, it may imply an oil leak. You should get help from an HVAC specialist to fix this problem.

The Furnace Smells Like Sewer Odors

Sewer gas smells quite similar to rotting eggs, so first determine the possibility of a natural gas leak. If that’s not the source, your home's sewer lines could have an issue, such as a dry trap or sewer leak. Flush water down all your drains, including the basement floor drain, to replenish dry sewer traps. If the smell lingers, go ahead and contact a sewer line repair company.

Contact Pardee Service Experts for Furnace Repair

If you're still uncertain, call an HVAC technician to check and repair your furnace. At Pardee Service Experts, we deliver comprehensive diagnostic services to pinpoint the problem before we figure out the best solution. Then, we recommend the most viable, cost-effective repairs, along with an up-front estimate for each option. 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 Pardee Service Experts office today.

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