Duct Cleaning

Duct cleaning businesses, are presenting their service as a procedure that every normal, properly functioning, duct system is in need of.    If you invite a Duct Cleaning Service to your home, most likely they will find a duct system that needs cleaning.

 

Duct Cleaning is not a preventive maintenance procedure.  It should only be part of a solution to a rare problem, but that is not the way it is being presented.   The “EPA does not recommend that the air ducts be cleaned routinely, but only as needed”.

If an accurate diagnosis determines that duct cleaning is necessary, it should only be done as part of an overall systemic approach.   All practical corrective measures should be made to ensure the problem does not return.
 

Harmless To The Duct System?

     Duct cleaning is also being presented as a procedure that is completely harmless to the duct system.   There is no discussion of the risk of damage that can result from pushing large vacuum hoses with a rotating brush on the end through the system (The most common procedure).    Most residential duct systems are constructed with fiberglass duct board which is cut with a knife and fastened together with tape.  After years of being in the hot attic the tape is weakened.   Pushing the cleaning hoses with the rotating brush through the system can further weaken the connections causing air leaks.  There should be a risk/benefit approach to duct cleaning only after an accurate diagnosis has been made.

Better Health?

    The marketing strategy is that cleaning any duct system will result in improved breathing and better health, but does it?   There is “information” supporting both sides.

  The best approach is to “attempt” to find independent studies.  It has been said that there is no such thing as pure science because science needs funding, and funds come from a source for a reason, and that reason can affect the outcome.
     That being said, the best source is usually studies done by universities, and another can be those performed by government agencies, taking into consideration the possible “reasons” for the funding.  Investigative reports done by news agencies, especially hidden-camera reports,  can be very instructive as you can see the reaction of these service providers as they are confronted with the evidence.    As you compare the different studies and reports, you will find a common thread in the findings.    

Here are some of the findings:

1)   Promise of Improved Health

The EPA says “Duct cleaning has never been shown to actually prevent health problems.”

2)   Removal of Dust Mites

     Clemson University says, “Dust mites do not live in air ducts in homes. Many people spend much time and money cleaning the air ducts to reduce dust mites. This is not necessary because dust mites need about 70% relative humidity or higher, and they need food. Areas where people spend much time, like in bed or a favorite plush chair, are prime sites for dust mites. The top part of mattresses containing fibrous material is a favorite place for dust mites during warm and humid times. The deeper parts of mattresses may provide protected areas for the dust mites during unfavorable conditions. Clothing is used by dust mites as transportation from room to room or even from house to house.”

    Frequent HEPA  filtered vacuuming and dusting along with removing  or covering  dust mite breeding grounds are the best strategy.   

  3)  Cleaning and/or treating mold.

     Mold is typically not found growing in the ductwork.   If it is growing it is usually only found in the Air Handler.  The EPA says, “If you have insulated air ducts and the (fiberglass) insulation gets wet or moldy it cannot be effectively cleaned and should be removed and replaced.”

  4)  Construction debris left in the ductwork.

        Even if construction debris is found in the ductwork, as it can be on rare occasions, it is not harmful.   Construction debris is very small pieces of what your house is made of.  And if there is still any left in the ductwork, it is not going anywhere, nor is it causing any harm.

Conclusion

“A duct cleaner says we need cleaning, but how can I know this is the case?” 

 

Occupational Health and Safety, in an article titled  “Ten Questions about Duct Cleaning”, answers this question.  “Remember, duct cleaning is a competitive business.  You have probably seen their advertisements.  Don’t be taken in by extreme claims  (e.g., “EPA says ducts should be cleaned every year” or “Our customers have reported no allergy symptoms following cleaning,” and so forth.)   Before you actually contract for duct cleaning, you should be able to answer yes to these questions:

  • Are there observable or known contaminants in the ductwork?
  • Has testing or observation confirmed their type and quantity?
  • Can or do they (or their odors or byproducts) leave the duct and enter the occupied space?
  • Do you have a good idea of the source of these contaminants? Can the source be controlled? (If not, cleaning is only a temporary measure.)
  • Will the proposed duct cleaning effectively remove (neutralize, inactivate) the contaminants?
  • Is duct cleaning the only (or, the most cost-effective) solution?
  • Have you identified a qualified and reputable duct cleaning firm?
  • Have you checked the firm’s references?
  • Has the firm a sensible, sound approach?  Do they have the right kind of equipment? Do they belong to and follow NADCA recommendations? (See the next question.)
  • Will the cleaning process protect your HVAC equipment and the occupants of the space during cleaning?
  • Will they give you a guarantee the duct will be clean after completion?