I did some research into this subject not too long ago, for my
employer. It turns out there is a lot more to this industry than I
ever imagined. Here is what I reported to him.
First, some useful links on the subject:
http://healthandenergy.com/air_duct_cleaning.htm " - two very useful
articles about the history and effectiveness of duct cleaning
- the official consumer
article from the EPA, referenced and paraphrased in many articles on
information from Canada's housing agency
http://www.nadca.com - home page of the National Air Duct Cleaning
Association, containing consumer information and a listing of certified
Based on these and other sites, here is a summary of the information
-Air duct cleaning on a yearly basis is not required or recommended.
The EPA recommends at most that it be done on an "as needed" basis, and
even the NADCA recommends it only every 5-7 years.
-Whether air duct cleaning actually provides any health benefits or
improves indoor air quality is still under debate. Improvements in
indoor air quality may best be achieved by removing shoes on entry, not
allowing pets indoors, frequent vacuuming (with central vacuums being
particularly good for this), and replacing filters on HVAC equipment.
-Despite the claims of some cleaners, dust mites do not breed in air
ducts. They breed in carpets, beds, and upholstery, and are thus best
removed with a vacuum cleaner.
-The duct cleaning industry is full of fraudulent practitioners, making
broad claims and offering very low prices (often supplemented with
add-on fees). The EPA and NADCA caution consumers against these
unlicensed, "blow and go" cleaners, warning that an improper job can
actually worsen indoor air quality. The EPA estimates that a proper
duct cleaning job costs about $450-$1000 and takes about 4-8 hours; any
contractor claiming less should be suspect. The EPA provides the
following checklist for choosing a cleaner:
-A proper duct cleaning job should include all items on the following
checklist: http://www.nadca.com/consumer_info/post_clean_checklist.asp .
-The use of spray sealants and chemical biocides is of questionable
value, and may actually pose health risks. None of these chemicals
have yet been tested or approved by the EPA.
I hope this information is helpful.