Why Your Furnace Has a Strange Smell

As the weather gets colder and you switch from cooling to heating your home, some homeowners are worried about weird furnace smells filling the air. Learn what the most common furnace smells mean and how worried you should be about each one.

The Furnace Smells Musty

Musty furnace odors usually indicate mold growth hiding in the HVAC system. To avoid subjecting your family to allergy-inducing mold, address this problem as soon as possible.

A clogged air filter can encourage mold, so getting rid of the smell might be as easy as swapping out filter. If that doesn’t work, the AC evaporator coil placed near the furnace may be to blame. This component collects condensation, which can stimulate mold growth. You'll want a professional’s help to examine and clean the evaporator coil. When this still doesn't help, start thinking about requesting air duct cleaning. This service removes hidden mold, regardless of where it's hiding in your ductwork.

The Furnace Smells Like Rotten Eggs

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

If you notice a rotten egg smell around your furnace or out of your vents, shut down the heater immediately. If you remember where the main gas supply valve is, shut that off as well. Then, get out of the house and contact 911, as well as your gas company. Don’t go back in 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 might mean the heat exchanger cracked open. This important component contains combustion fumes, including carbon monoxide, so cracks could pump 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, reach out to an HVAC professional for an inspection. Consider replacing your furnace if a cracked heat exchanger is the culprit. For your family's safety going forward, ensure you have working CO detectors on every floor of your home.

The Furnace Smells Dusty

When you start the furnace for the first time each fall, you can expect a dusty odor to show up for a brief moment. 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 a 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 safely out of your home. A smoky smell can mean the flue is clogged, and now fumes are backdrafting 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 as soon as you can to schedule a repair.

The Furnace Smells Like It's Burning Plastic

Overheating and burned electrical components are the most common reason for a burning plastic smell to appear. A faulty fan motor is another common cause. If you don’t tackle the problem, an electrical fire may start, or your furnace could suffer from irreparable damage. Turn off the heating system right away and contact an HVAC technician for help identifying and repairing this unusual furnace smell.

The Furnace Has an Oily Smell

If you use an oil furnace, you could detect this stench when the oil filter becomes blocked up. Try replacing it to see if that fixes the problem. If the smell persists for more than one day after carrying out this step, it could suggest an oil leak. You should get help from an HVAC professional to address this problem.

The Furnace Reeks of Sewer Odors

Sewer gas smells very similar to rotting eggs, so first determine the possibility of a natural gas leak. If that’s not the issue, the sewer lines could have an issue, like a dry trap or sewer leak. Pour water down all your drains, including the basement floor drain, to refresh dried-up sewer traps. If the smell lingers, you’ll need to contact a sewer line repair company.

Contact Robinson Service Experts for Furnace Repair

When in doubt, contact an HVAC technician to check and repair your furnace. At Robinson Service Experts , we deliver complete diagnostic services to identify the problem before the work begins. 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 problem, 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 Robinson Service Experts office today.