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Dangerous Ducts: Are They In Your Home?

August 26, 2013

Is your ductwork a danger to your health?

Your home is filled with all manner of wires, cables, and pipes, all of which keep your home’s various utilities and appliances running smoothly. One of the most important but often under-appreciated elements in any home is the ducts. They keep air flowing thru your filter and into your home and help remove allergens and other unwelcome airborne debris. Ducts are also what bring us the wonder of climate-controlled rooms. They’re the lungs of your home.
But ducts—or at least those that aren’t well-maintained—present problems. They’re inefficient, raise your utility bills, and generally make your humble home a place of discomfort. Worse yet, bad ductwork can actually cost you your health and potentially your life! Here are some common culprits causing dangerous ducts.


Dust around the house is a fun mix of essentially everything drifting around your home—pet dander, bits of ash from your cigarettes, soil, pollen, insect bits, industrial pollution, and good ole human skin. Ducts that are storing a lot of dust will only blow that dust back into the air, which can cause sneezing, aggravate allergies, and make breathing difficult. Ducting that isn’t sealed well can introduced dust from your attic or under your house right into your home. Don’t let bad ducts get the better of your health and allergies.

Mold and Fungi

Mold and fungi can be found essentially anywhere containing moisture, like the pool of condensation from your air conditioner. A mold spore floating in the air will land in that pool and grow. It will continue to grow so long as there’s some moisture present.

That alone is pretty gross, but it gets worse. Because your ducts consist of a network running throughout your home, the mold has easy access to just about every nook and cranny of your home. Breathing in some mold spores can lead to respiratory issues that often resemble seasonal allergies, in addition to headaches, dizziness, and difficulty concentrating. Frequent contamination could lead to illness and respiratory issues all year long.


Asbestos is a mineral fiber and was used in various products to add strength and fire resistance. It is commonly found in homes that were built before the 1970s. In older homes, ducts are often wrapped using an asbestos blanket or asbestos paper tape for insulation.

When asbestos gets damaged you should start worrying, as it crumbles into a fine dust that is easily inhaled. Inhaling high levels of asbestos increases your risk of lung cancer, mesothelioma, and asbestosis. Symptoms of these diseases won’t manifest until 20 to 30 years after exposure.


Rats are one of the most common pests in the world. When they’re out in the cold, wet wild, your home looks like a haven of warmth, shelter, and free food.

You don’t have to get bitten by a rat to be in danger. They carry fleas, which may or may not harbor disease but are an extreme headache for anyone trying to get rid of them, especially in a non-toxic way. Then there’s the matter of droppings. Gross in their own right, a rat’s droppings and urine contain potentially harmful bacteria. Imagine those droppings sitting in your ducts as you turn on the heater. You’d be filling your home with the bacteria of rat poop. Yikes!


Fiberglass is a man-made material created to replace asbestos as a thermal barrier or insulation in homes today. Fiberglass is found all over your home, in walls, attics, under your house, and it’s also wrapped around your air ducts. When ducts are damaged or deteriorating, they can introduced particles of fiberglass into the air you breath. According to the American Lung Association– Inhaling fiberglass can reduce lung function and cause skin eye and throat irritation, in humans and animals. Some old types of ducting have no barrier between the fiberglass and the air stream and should be replaced immediately.

So, are dangerous ducts in your home? If you’re not sure of the status of your air ducting, call a professional air conditioning contractor like Bob Jenson A/C to assess them. The best way to mitigate any of these dangers is to perform regular maintenance on your duct systems. Keep your ducts clean, practice proper pest control, and have a professional check your ducts once a year.

About The Author

Bob Jenson

For over 45 years, Bob Jenson has been providing quality heating and air services to the San Diego community.

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