Uncovering the Causes of Smells Coming from Your Ducts

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Causes of Smells Coming from Your Ducts

Published by Derek Cormier

An HVAC system that uses ductwork to carry heated air from your furnace in the winter and cooled air from your air conditioner all summer is very common. And it’s such a common system because it is so effective. Generally, people are quite happy with their ductwork and the heating and cooling systems connected to it. But occasionally, there’s a problem. And sometimes, that problem is a bad smell.

If the vents from your ductwork are blowing a bad smell into your home along with your heated or cooled air, we can help you sort it out. First, let’s consider exactly what sort of bad smell you’re experiencing. That will help to determine what’s causing the odor so you can get the appropriate duct services in Satellite Beach, FL.


If the smell reminds you of damp basements or musty old books, chances are, you have a mildew problem in your ductwork. Mold loves to grow in dark places, but it can only survive where there’s plenty of moisture. This means there’s water in your ductwork. A technician can provide duct cleaning and assess whether the ducts need to be realigned to prevent moisture from pooling.


If the smell reminds you of garbage or the dirty cages of small pets, it’s likely that rodents have gotten into your ductwork. This is particularly concerning because they can do damage to the ducts themselves, which may need to be resealed.

A Gas Leak

If the smell reminds you of rotten eggs, you need to take immediate action. Natural gas is odorless, but a sulfur compound is added to help alert people to gas leaks. Breathing these fumes is very unhealthy, but the scariest risk is fire or explosion. Do not flip any switches or plug in or unplug anything. This could cause a spark. If you know how to shut off the main gas valve to your home, do so. Then evacuate, and from a safe distance or a neighbor’s phone, call your gas provider’s emergency number or 911.


If the smell reminds you of something burning, it’s possible that it’s just a small scrap of paper or plastic or perhaps a crayon that has gotten into the ductwork and is heating up. But it’s also possible that something—likely the blower fan motor—is overheating and burning out. As this can cause damage to other components of your HVAC system, turn it off and get professional help right away.


If the smell reminds you of high school biology classes, or of pickles and chemicals, particularly when you’re using your furnace, this is another very serious issue. There may be a crack in your heat exchanger. Turn off the heating system immediately and make sure your carbon monoxide detectors are working, because the heat exchanger keeps the combustion gasses separate from the air you breathe, and any cracks can allow toxic fumes to escape.

If there is any unpleasant odor coming from your ductwork, we will help you sort it out.