What’s That Smell Coming From My Furnace?

Worried senior citizen with a smartphone looking concerned.

If your furnace is producing a strange smell, you should always treat it with caution. While the cause for the odor may be benign, it could just as easily be harmful to inhale. When in doubt, always open windows to ensure ventilation, and evacuate your Saint Charles, MD home.

For your convenience and protection, our Mission Comfort team developed a list of five common furnace smells and what they mean.

1. Burnt Plastic

If you just turned on your furnace for the winter, your nostrils may detect a burning smell. If this is the case, you don’t need to panic yet. Furnaces collect dust over time, which is burnt off when you first turn on your furnace.

It might be a good idea to check your filter to see if it needs replacing. However, if the smell doesn’t dissipate after about 30 minutes, contact one of our heating, ventilation, and air conditioning (HVAC) professionals to check it out.

2. Diesel or Oil

The smell of diesel or oil could point to many things. Look to be sure you don’t see any smoke or flames coming from the unit. If you do, shut down your furnace immediately and call our Mission Comfort professionals immediately for guidance on what to do next.

If you don’t spot an obvious issue, the problem could be one of a number of issues—from a plugged nozzle to a clogged chimney to even a cracked heat exchanger. Some are simple fixes while others are more serious. If the smell doesn’t dissipate in a couple hours, call us to discuss your options.

3. Musty and/or Mildewy

This smell is usually indicative of dirty air ducts. Over time, your ductwork becomes overrun with dust, debris, mildew, and mold. Your home’s ventilation carries this smell throughout the house.

Not only is this smell unpleasant; it’s bad for your indoor air quality (IAQ). Indoor air quality can be decreased by several contributing factors. According to the US Consumer Product Safety Commission (CPSC), most Maryland homes have more than one source that contributes to indoor air pollution. To solve the smell issue, have your ducts cleaned by a professional.

4. Metallic and/or Electric

This is likely the smell of your motor overheating. In this case, it’s a good decision to power down your furnace immediately. Then, schedule a repair with one of our professional technicians.

5. Formaldehyde

If you can smell a pungent chemical smell similar to formaldehyde, this presumably means you have a cracked heat exchanger. You should evacuate immediately and call 911. Cracked heat exchangers are known to release carbon monoxide (CO) fumes that are potentially lethal when inhaled.

Contact Us for All Your Furnace Needs

Our team at Mission Comfort hopes you found this list of common furnace smells useful. Remember, always treat chemical smells with the utmost wariness. Call us at 301.450.8414 or request service online here in Saint Charles, MD, or any of its surrounding areas with any additional questions or to schedule service.

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