Dear Angie: We have had a problem with dust in our 2-year-old house. We had someone inspect our air ducts to see if they needed to be cleaned. His inspection revealed that we had a lot of dust in our coils and air ducts. He said the most likely reason was that the builder ran the air-conditioning unit without air filters in place. He recommended that we clean the coil, remove and clean the blower and replace at least 25 air ducts. He recommended replacing the ducts rather than cleaning them because the ducts were made of plastic and difficult to clean properly. The estimated cost is more than $10,000 and could be more if more air ducts need to be replaced. Is it common to replace your air ducts because they are too dirty to clean properly? — Anonymous
Dear Anonymous: There are a number of factors that will determine whether you can clean or need to replace your air ducts. The first is the type of ductwork you have. In most cases, most types of ductwork can be cleaned easily, especially in a newer home.
Metal ductwork with no interior lining almost assuredly can be cleaned. If the ducting is constructed of fiber board, though, it cannot be cleaned as easily. If the contamination is severe, it probably needs to be replaced.
However, you say your ducts are plastic, which I'm inclined to think means you have flexible ductwork. Flex ductwork is typically made of a wire coil covered by a thin, flexible plastic wall and wrapped in insulation and foil backing. If the flex ducts have only dust or debris in them, they should be able to be cleaned easily by a qualified professional with the right tools. However, if the flex ducts have mold growth — depending on the level of contamination — they could need to be replaced.
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Before you have the ductwork cleaned — or replaced, if that's necessary — it's important you find the source of the dust. Every duct system has some residual dust, regardless of how well it is cleaned, but because your home was built recently, it shouldn't need a duct cleaning so soon.
However, there are exceptions to that. If the builder ran the heating and cooling system during the construction phase, that could be at the root of the issue. It's also possible the entire HVAC system needs to be sealed better. Air leakages can draw additional dirt and dust into the system. Having a blower door test done will help you determine exactly where leaks might be occurring.
It all really comes back to how well the system was installed. Some reputable air-duct cleaners have told me they've seen new houses where the systems and ducts are so poorly done that they require re-engineering and a major renovation, but few recommend total replacement. Unfortunately, some companies use scare tactics, like saying there is mold present, to oversell unnecessary duct cleaning or replacement.
My advice is to do your research and find at least two more companies that have solid reputations and specialize in air-duct systems. Many companies offer multiple services, including carpet and chimney cleaning, but you really need someone who focuses solely on air-duct systems and is in good standing with the National Air Duct Cleaners Association. Look for credible online reviews and testimonials from clients to get a feel for how these companies resolve issues like yours, and ask for detailed estimates so you can compare apples to apples.