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 filling the air. Find out what the most common furnace smells could suggest and how concerned you should be about each one.

The Furnace Smells Musty

Musty furnace odors almost always indicate mold growth somewhere in the HVAC system. To avoid subjecting your family to these microorganisms, address this problem as quickly as possible.

A damp air filter can lead to mold, so eliminating the smell could be as simple as swapping out filter. If that doesn’t work, the AC evaporator coil fastened near the furnace might be the culprit. This component gathers condensation, which can induce mold growth. You'll want a professional’s help to check and clean the evaporator coil. When all else fails, take a look at investing in air duct cleaning. This service eliminates hidden mold, regardless of where it’s growing in your ductwork.

The Furnace Smells Like Spoiled Eggs

This is one of the most concerning furnace smells since it most likely suggests a gas leak. The utility company adds a special 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 originating from your air ducts, switch off the heater straightaway. If you can find where the main gas supply valve is, shut that off as well. Then, leave the house and call 911, in addition to 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 standing close to the furnace, this may mean the heat exchanger is cracked. This vital component houses combustion fumes, like carbon monoxide, so a crack might pump unsafe levels of CO gas into your home.

Carbon monoxide poisoning could be lethal, so switch off your furnace immediately 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 to blame. For your family's safety going forward, ensure you have reliable CO detectors on all floors of your home.

The Furnace Smells Dusty

When you fire up the furnace for the first time each fall, you can expect a dusty odor to appear for a little while. This is the smell of six months’ worth of dust burning away as the furnace wakes from its summer slumber. As long as the smell disperses 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 up and out of your home. A smoky smell will sometimes mean the flue is blocked, and now fumes are flowing back into your home. The odor may permeate the entire house, jeopardizing your family’s health if you neglect it. So switch off the furnace and call 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 make an appearance. A faulty fan motor is another possibility. If you don’t address the problem, an electrical fire might start, or your furnace could suffer from irreparable damage. Shut off the heating system immediately and contact an HVAC technician for help diagnosing and repairing this unusual furnace smell.

The Furnace Has an Oily Smell

If you have an oil furnace, you may pick up on 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 might suggest an oil leak. You should get help from an HVAC expert to address this problem.

The Furnace Smells Like Sewer Odors

Sewer gas smells pretty similar to rotting eggs, so first determine the potential for a natural gas leak. If that’s not the problem, the sewer lines might have an issue, like a dry trap or sewer leak. Flush water down all your drains, including the basement floor drain, to fill dried-up sewer traps. If the smell persists, go ahead and contact a sewer line repair company.

Contact R & M Climate Control Service Experts for Furnace Repair

If you're still uncertain, call an HVAC technician to assess and repair your furnace. At R & M Climate Control Service Experts, we offer complete diagnostic services to determine 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 every option. Our ACE-certified technicians can resolve just about any heating problem, and we back our work with a 100% satisfaction guarantee for one year. To learn more about why your furnace smells bad or to request furnace repair near you, please contact your local R & M Climate Control Service Experts office today.

chat now widget box