In most American homes, the HVAC unit and ductwork is placed in the attic. Here in Houston, attic temperatures can easily reach 120 degrees or more during the summer. You can imagine that does to plastic ductwork. It literally cuts the service life in half.

If you decide to have your ducts cleaned, first make absolutely sure they need it. According to the EPA, just having dust in the ducts is not sufficient reason to have them cleaned. The reason is that air flow through the ducts forms a static charge on the walls of the duct which attracts and traps dust so having your ducts coated with a layer of fine dust is actually normal. However, if the layer of dust is so thick that it’s blowing into the house or if it’s getting wet and growing mold, then cleaning the ducts may be justified.

Second, if you decide to get your ducts cleaned, make absolutely sure you get a qualified and licensed contractor to do it. A company that doesn’t know what they’re doing will actually create a much, much bigger IAQ problem. Make sure you check references including a call to the Better Business Bureau.

Last, compare the cost of cleaning the ducts against the cost of having them replaced. It may be more cost effective. Keep in mind however, that the price from a professional duct cleaner should also include cleaning the cooling coil and other system components (make sure you check) so these may have to be added to the replacement cost.

One word of warning. Many duct cleaning companies will try to sell you on the application of special disinfectants and/or antimicrobial coatings – many of which are quite pricey. These are not needed in most cases but there are special cases in which they make sense. If the contractor recommends them, make sure you get them to explain why in a way that makes sense to you.

A great resource is the EPA’s publication “Should You Have the Air Ducts in Your Home Cleaned?” available at http://www.epa.gov/iaq/pubs/airduct.html

Hiram

SAM