Why Your Furnace Has a Strange Smell

As the weather cools down and you switch from cooling to heating your home, you might be worried about weird furnace smells in the air. Find out what the most common furnace smells could suggest and how concerned you should be about them.

The Furnace Smells Musty

Musty furnace smells almost always indicate mold growth someplace in the HVAC system. To avoid subjecting your family to allergy-inducing mold, handle this problem right away.

A clogged air filter can harbor mold, so getting rid of the smell can be as easy as replacing the filter. If that doesn't help, the AC evaporator coil fastened near the furnace may be to blame. This component gathers condensation, which can trigger 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 requesting air duct cleaning. This service removes hidden mold, regardless of where it’s growing in your ventilation.

The Furnace Smells Like Spoiled Eggs

This is one of the most nerve-wracking furnace smells because it most likely implies a gas leak. The utility company puts in a particular substance known as mercaptan to the natural gas supply to make leaks more easily detected.

If you notice a rotten egg smell around your furnace or coming from your air ducts, switch off the heater immediately. If you remember where the main gas supply valve is placed, shut that off as well. Then, evacuate your home and contact 911, in addition to your gas company. Don’t enter the house until a professional tells you 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 might mean the heat exchanger is cracked. This important component houses combustion fumes, including carbon monoxide, so cracks could allow unsafe levels of CO gas into your home.

Carbon monoxide poisoning can be fatal, so shut off your furnace right away if you recognize a sour odor. Then, call 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 working 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 probably expect a dusty odor to appear for a brief moment. This is the smell of six months’ worth of dust burning off as the furnace wakes up. As long as the smell disperses within one 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 safely out of your home. A smoky smell will sometimes mean the flue is clogged, and now fumes are settling back into your home. The odor can reach through the entire house, risking your family’s health if you ignore it. So switch off the furnace and contact a professional as soon as you can to arrange for repair.

The Furnace Smells Like It's Burning Plastic

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

The Furnace Has an Oily Smell

If you use 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 addresses the problem. If the smell lingers for more than one day after completing this step, it could suggest an oil leak. You should get help from an HVAC professional to handle this problem.

The Furnace Reeks of 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 issue, the sewer lines could have an issue, for example a dry trap or sewer leak. Pour water down your own drains, including the basement floor drain, to replenish dried-out sewer traps. If the smell lingers, you should contact a sewer line repair company.

Contact Bob Brown Service Experts for Furnace Repair

If you're still uncertain, get in touch with an HVAC technician to examine and repair your furnace. At Bob Brown Service Experts, we perform comprehensive diagnostic services to determine the problem before we figure out the best solution. Then, we suggest the most viable, cost-effective repairs, alongside an up-front estimate for each 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. For details about why your furnace smells bad or to request furnace repair near you, please contact your local Bob Brown Service Experts office today.

chat now widget box