Why Your Furnace Has a Strange Smell

As the weather gets colder and you swap from cooling to heating your home, you may be worried about unusual furnace smells filling the air. Find out what the most common furnace smells mean 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 exposing your family to these microorganisms, handle this problem right away.

A damp air filter can harbor mold, so eliminating the smell might be as easy as swapping out filter. If that doesn't help, the AC evaporator coil mounted near the furnace may be to blame. This component gathers condensation, which will sometimes induce mold growth. You'll be better off with 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 cleans away hidden mold, no matter where it’s growing in your ventilation.

The Furnace Smells Like Rotten Eggs

This is one of the most nerve-wracking furnace smells due to the fact that it probably implies a gas leak. The utility company adds a particular substance known as mercaptan to the natural gas supply to make leaks easier to notice.

If you recognize a rotten egg smell near your furnace or originating from your vents, shut down the heater straightaway. If you know where the main gas supply valve is, shut that off also. Then, get out of the house and contact 911, as well as your gas company. Don’t enter 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 close to the furnace, this might mean the heat exchanger cracked open. This important component houses combustion fumes, like carbon monoxide, so cracks might pump unsafe levels of CO gas into your home.

Carbon monoxide poisoning has the potential to be deadly, so turn 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 to blame. For your continued safety going forward, make sure you have functional CO detectors on every floor of your home.

The Furnace Smells Dusty

When you fire up the furnace for the first time every fall, you should expect a dusty odor to fill the house for a little while. 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 dissipates 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 safely 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, endangering your family’s health if you neglect it. So turn off the furnace and contact a professional as soon as you can to arrange for repair.

The Furnace Smell Resembles Burning Plastic

Overheating and melted electrical components are the most common reason for a burning plastic smell to make an appearance. A malfunctioning fan motor is another common cause. If you don’t address the problem, an electrical fire could start, or your furnace could suffer from irreparable damage. Disable the heating system immediately and contact an HVAC technician for help troubleshooting and repairing this weird furnace smell.

The Furnace Has an Oily Smell

If you have an oil furnace, you might notice this odor when the oil filter becomes clogged. Try replacing it to see if that fixes the problem. If the smell persists for more than a day after taking care of this step, it could indicate an oil leak. You should get help from an HVAC professional to fix this problem.

The Furnace Smell Resembles Sewer Odors

Sewer gas smells very similar to rotten eggs, so first determine the possibility of a natural gas leak. If that’s not the source, your home's sewer lines may have an issue, for example a dry trap or sewer leak. Try pouring water down the drains, including the basement floor drain, to refresh dry sewer traps. If the smell lingers, go ahead and contact a sewer line repair company.

Contact Service Experts Heating & Air Conditioning for Furnace Repair

If you're still unsure, contact an HVAC technician to assess and repair your furnace. At Service Experts Heating & Air Conditioning, we offer thorough diagnostic services to determine the problem before repairs begin. Then, we suggest the most viable, cost-effective repairs, as well as an up-front estimate for each option. Our ACE-certified technicians can resolve just about any heating malfunction, 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 Service Experts Heating & Air Conditioning office today.

chat now widget box