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 strange furnace smells floating in the air. Find out what the most common furnace smells could mean and how concerned you should be about each one.

The Furnace Smells Musty

Musty furnace odors almost always indicate mold growth hiding in the HVAC system. To avoid exposing your family to allergy-inducing mold, tackle this problem right away.

A damp air filter can lead to mold, so eliminating the smell could be as simple as swapping out filter. If that doesn't help, the AC evaporator coil mounted near the furnace could be the root of the problem. This component gathers condensation, which can stimulate mold growth. You'll want a professional’s help to examine and clean the evaporator coil. When the problem still won't go away, take a look at scheduling air duct cleaning. This service eliminates hidden mold, regardless of where it's hiding in your ventilation.

The Furnace Smells Like Rotten Eggs

This is one of the most concerning furnace smells due to the fact that it most likely implies a gas leak. The utility company adds a useful substance called mercaptan to the natural gas supply to make leaks more easily detected.

If you recognize a rotten egg smell around your furnace or coming from your air ducts, switch off the heater immediately. If you know where the main gas supply valve is placed, shut that off also. Then, evacuate your home and contact 911, as well as your gas company. Don’t reenter the house until a professional can verify it’s safe.

The Furnace Has a Sour Stench

If you notice a sour smell that stings your nose while close to 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 lethal, so shut off your furnace as soon as possible if you notice 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, see to it that 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 each fall, you can expect a dusty odor to appear for a few minutes. 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 dissipates 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 up and out of your home. A smoky smell can mean the flue is clogged, and now fumes are backdrafting into your home. The odor might eventually reach the entire house, risking your family’s health if you ignore it. So shut down the furnace and call a professional as soon as you can to request furnace repair.

The Furnace Smells Like Burning Plastic

Overheating and melting electrical components are the most likely reason for a burning plastic smell to make an appearance. A failing fan motor is another possibility. If you don’t correct the problem, an electrical fire could start, or your furnace could suffer from irreparable damage. Turn off the heating system immediately and contact an HVAC technician for help identifying and repairing this unpleasant furnace smell.

The Furnace Has an Oily Smell

If you have an oil furnace, you may detect this stench whenever the oil filter becomes blocked up. Try replacing it to find out if that fixes the problem. If the smell lingers for more than one day after carrying out 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 Smells Like Sewer Odors

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

Contact Parker Pearce Service Experts for Furnace Repair

If you're still unsure, get in touch with an HVAC technician to check and repair your furnace. At Parker Pearce Service Experts, we deliver complete diagnostic services to identify the problem before repairs begin. Then, we recommend the most viable, cost-effective repairs, along with an up-front estimate for all options. Our ACE-certified technicians can manage just about any heating repair, and we back our work with a 100% satisfaction guarantee for one year. For details about why your furnace smells bad or to request furnace repair near you, please contact your local Parker Pearce Service Experts office today.

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