Why Your Furnace Has a Strange Smell

As the weather turns cold and you switch 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 mean and how worried you should be about each one. 

The Furnace Smells Musty 

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

A clogged air filter can lead to mold, so wiping out the smell can be as easy as getting a new filter. If that fails to remove the smell, the AC evaporator coil placed near the furnace might be the root of the problem. This component collects condensation, which could induce mold growth. You’ll need a professional’s help to inspect and clean the evaporator coil. When the problem still won’t go away, consider requesting air duct cleaning. This service cleans away hidden mold, regardless of where it’s growing in your ductwork. 

The Furnace Smells Like Rotten Eggs 

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

If you notice a rotten egg smell close to your furnace or originating from your air ducts, shut down the heater immediately. If you can find where the main gas supply valve is placed, shut that off also. Then, leave the house and contact 911, as well as your gas company. Don’t reenter 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 near64} the furnace, this may mean the heat exchanger is cracked. This important component houses68} combustion fumes, including carbon monoxide, so a crack may allow unsafe levels of CO gas into your home. 

Carbon monoxide poisoning could be deadly, so shut 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 responsible. For your health and safety going forward, see to it that you have functional CO detectors on every floor of your home. 

The Furnace Smells Dusty 

When you start the furnace for the first time each fall, you probably expect a dusty odor to appear for a few minutes. This is the smell of six months’ worth of dust burning up as the furnace wakes from its summer slumber. As long as the smell disperses within one day, you have nothing 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 might eventually reach the entire house, jeopardizing your family’s health if you neglect it. So turn off the furnace and call a professional right away to request furnace repair. 

The Furnace Smell Resembles Burning Plastic 

Overheating and melted electrical components are the most likely reason for a burning plastic smell to appear. A failing fan motor is another possibility. If you don’t address the problem, an electrical fire could start, or your furnace could end up with irreparable damage. Turn 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 could detect this odor if the oil filter becomes blocked up. Try replacing it to find out if that addresses 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 fix this problem. 

The Furnace Reeks of Sewer Odors 

Sewer gas smells quite similar to spoiled eggs, so first eliminate the likelihood of a natural gas leak. If that’s not the source, your sewer lines could have an issue, such as a dry trap or sewer leak. Try pouring 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 Service Experts Heating, Air Conditioning & Plumbing for Furnace Repair 

If you’re still uncertain, get in touch with an HVAC technician to assess and repair your furnace. At Service Experts Heating, Air Conditioning & Plumbing, we offer thorough diagnostic services to identify the problem before we figure out the best solution. Then, we recommend the most viable, cost-effective repairs, alongside an up-front estimate for every option. Our ACE-certified technicians can manage just about any heating repair, 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 Service Experts Heating, Air Conditioning & Plumbing office today. 

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