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What That Smell Coming From the Furnace Could Mean

Even in San Antonio’s mild winters, a reliable furnace is a necessity for comfort. So when you notice a strange furnace smell, it’s understandably worrying. While some funny smells from the furnace are easy to get rid of, others signal serious trouble.

Temporary Odor Issues

When you first turn your furnace on in the winter, you’ll likely notice the odor of burning dust. During the off season, dust collects on your heat exchanger and other furnace components. When the furnace begins producing heat again, this dust burns off. It’s a normal furnace smell and should last only a few hours.

A damp or musty odor is also common when you first start up your furnace in winter. This often comes from a small amount of mold formed inside the ducts and should dissipate within a day. Also make sure your air filter and humidifier are clean and mold-free. If the odor persists, you might have an extensive mold problem. A technician can inspect your furnace and ducts to identify the source of the odor.

Odors That Mean Trouble

A sulfur or rotten egg smell indicates a natural gas leak. Leave the house and contact your gas company immediately. The odor of chemicals or formaldehyde suggests a cracked heat exchanger, which poses the risk of a carbon monoxide leak. Turn off the furnace and call a technician.

The smell of hot or burning wires, plastic or other electrical parts strongly suggests your system is at risk for a fire. Turn off the furnace and contact a technician. The cause could be damaged wiring, an overheating motor or another malfunctioning component. A foreign object stuck in the duct, such as loose insulation, can also cause this issue.

If you have an oil furnace and smell smoke or oil, change the oil filter. If that doesn’t stop the odor, contact a technician. It’s possible your system just needs a cleaning, but there’s also a risk that you have a damaged component that could start a fire.

If you’re concerned about a furnace smell, contact us at Beyer Boys in the San Antonio area.

Our goal is to help educate our customers in the greater San Antonio, Texas area about energy and home comfort issues (specific to HVAC systems).