Phew, What’s That Smell? 4 Furnace Smells to Watch For

Furnaces heat and distribute air through your home. From time-to-time problems may pop up with a furnace that cause unpleasant or weird odors, they wither come from the furnace itself or blowing out of the ducts and vents. Here are four different furnace smells and what you might want may be causing them!

Common Furnace Smells

Dusty Burning Smell

For some people, this odor is a seasonal occurrence. Over the summer, furnaces are usually not in use. As a result, dust accumulates inside of them. When fall arrives and the furnace is turned on, the dust is burned away. If the furnace has not been cleaned before being used, a strange burnt dust smell will likely linger for a few minutes.

There’s little no risk of fire or health concerns stemming from burnt dust. However, if the smell bothers you, you may want to book a furnace cleanup or tuning before turning your unit on for the first time. This ought to eliminate or minimize dust smells while also ensuring your furnace is operating safely and efficiently.

Gas Smell

If you smell sulfur or rotten egg odor coming from your furnace or vents, you may have a gas leak. Whether the smell comes from your vents or from the furnace itself, shut the unit off immediately. Leave your home as quickly as you can, making sure to turn the gas off on the way out if possible. Then, call your gas company — they will be able to safely shut the gas off to your home so that a technician can diagnose the issue.

Natural gas leaks can result from a cracked or otherwise damaged heat exchanger or due to issues with the gas line itself. In either case, don’t try to diagnose the leak yourself. Instead, trained technicians have the equipment and knowledge to safely fix whatever’s wrong once the gas has been turned off.

Moldy, Damp, or Funky Smells

Furnaces don’t tend to have problems with moisture build-up, but it can occur in areas with high humidity. If you detect a sour, earthy, or strange smell coming from your vents or furnace, you may have a moisture issue in your system.

Moisture is one of a few ingredients that contribute to mold and bacteria growth, the others being darkness, oxygen, and warmth. Unfortunately, your ventilation system has the last three items covered, so if moisture gets trapped in the system somehow, you can very quickly have a mold problem on your hands!

Don’t freak out–first, make sure there isn’t a more obvious source of the smell, like air intakes near garbage cans or compost bins. See if the smell is localized to one room or if it’s everywhere. If it looks like it’s coming from the vents or furnace, call a technician to take a look. To tackle a mold issue, you need to remove it and figure out why there’s extra moisture in the house. If it’s a leaky pipe or a damaged roof, that’s an easy fix. If the air is just too damp, get a dehumidifier to reduce moisture, preventing mold and making your home more comfortable.

Another possible cause of sour smells in your ventilation system is pest infestation. Rodents and other small pests can cause all sorts of damage to the ventilation system. Their urine and feces can collect in air ducts, spreading foul odors and potentially dangerous microbes through your home. Pests can die and decay inside ducts as well. An inspection will quickly identify any pest issue you may have.

Burning Plastic Furnace SmellsIf you notice a burning plastic smell coming from your furnace, you may have an electrical issue. The blower fan and other electrical components in your furnace cycle on and off frequently, which can cause them to wear out over time. If this happens, they may start generating more heat than usual and cause the materials in the fan motor to overheat and melt, resulting in a burning plastic smell.

Frayed or poorly connected wires in your furnace. Either of these issues can cause short fuses, damage other furnace components, or even cause electrical fires. If you smell burning plastic, turn your furnace off immediately and call a furnace repair technician!

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