Ducts can be one of the filthier aspects to our home, and the thought of breathing in dirty air can give someone nightmares about respiratory problems and disease. I’ve been called on dozens of occasions by friends and acquaintances who seek advice on whether their air ducts should be cleaned – either by their own inclination, or because a duct cleaning contractor offered them an apparently sweet deal on their services.
It seems that every facet of a house needs to be cleaned every once in a while, so it is natural for both residents and contractors to assume that air duct cleaning is a necessary routine maintenance procedure. After all, ducts constantly wheeze particulates of dust which cling to its surface and collect in supply registers. But despite how necessary it may seem, the benefits of regularly cleaning your ducts are debatable at best. The real question should not be how often a duct should be cleaned; it should be, “Is duct cleaning worth it?”
In fact, there are very few circumstances besides visibly witnessing large clumps of dust being blown through your system that merit a good cleaning. As long as you keep your filter replaced or cleaned every so often, there’s not much to worry about from your air ducts. There are, however, two circumstances that absolutely require a thorough duct cleaning.
Mold can be particularly insidious in a duct system, where spores might become dispersed throughout your home. Not all molds are necessarily toxic, and some might not cause any kind of noticeable harm. But no matter the strain, allowing mold to spread freely throughout your system is always a terrible idea, especially if anyone in your family is experiencing symptoms related to mold exposure. The easiest way to check for mold is to smell it; since air ducts transport air throughout the house, you should check your ducts if you smell mold anywhere in your house and can’t locate where it’s growing.
Visual confirmation can be difficult with a duct system unless you have specialized equipment, and attempting to disturb a mold colony to get a sample can cause a world of trouble since you’ll be scattering mold spores everywhere. The coloration of mold isn’t usually relevant, but black mold might mean you’re dealing with a particularly dreadful toxic strain that has received a lot of press: Stachbotrys chartarum.
Regardless of the strain, a confirmation of mold in your system unquestionably merits a professional cleaning. It’s also necessary to address the source of moisture, since mold can only prosper in a moist environment. You’ll need to have the house inspected for water leakages that might be reaching your ductwork. Alternatively, excess moisture might be a product of excessive condensation, which is a red flag that your system is pushing too hard and needs inspection. Sealing air duct leaks will help keep moisture out and greatly increase your energy efficiency.
Refrain from using harsh chemical biocides in your ductwork. Sheet metal found in ducts is an ideal nonporous material for a mild 1/10th water bleach solution. After the mold is dead, vacuum dead mold material out of your system − dead mold can still be harmful mold. And if any trace of mold exists throughout your HVAC system, it is only a matter of time before it spreads again, so thoroughness can’t be stressed enough.
Any critters or bugs that make their way into your air duct (such as mice, roaches, fleas, etc.) are not only difficult to reach in an air vent, but they’re also prone to kicking up allergens, leaving droppings, and spreading disease. Like mold, pests in your system can stir up a variety of symptoms, like allergy/sinus/asthma issues.
And as with mold, pest infestations in air ducts are problematic because it is a difficult to access space where harsh chemicals are unwise. Aerosol poisons are completely out, since it will linger in your system for days and inevitably lead to heavy intake on your family’s part. Any poison is a terrible idea, since you’ll leave a dead mouse to dry up in your system. In any case, pesticides are only a temporary solution. Bait like peanut butter traps are hit and miss, and can be messy. One viable trick is to use glue traps, but their application is limited.
The best method for purging your ductwork of pests is to remove the reason why they’re there. To be precise, use the Integrated Pest Management approach, which is more effective, cost efficient, and environmentally safe than any alternative. The gist of this approach is that inspection, identification, and treatment are necessary to eradicate pests. Proper sealing and maintenance are essential to deprive pests transportation, water, and food in your home.
While there is no definite word on whether regular duct cleaning is necessary, you should be mentally equipped to recognize when a problem exists and your air ducts require more drastic cleaning measures.
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Jason Wall is an HVAC technician of more than 23 years who occasionally writes for Griffith Energy Services. He spends his time enjoying life with his family and keeping up with professional baseball.