The Advanced Air Quality did the job for me. http://www.advancedairquality.ca/?gclid=CMLF84z47KQCFYVrKgod4XWl0Q
Charged at $199+$9/vent x 26 = $433+13%tax=$489.
One person did the job for about 3 hours. He worked pretty hard, although it is difficult to tell whether the duct is cleaned or not. There are many companies to do duct cleaning. Some companies will show you the inside duct before and after via a videocamera. Some other companies will show how much garbage has been vacuumed out from your duct. But this company did not show me anything. Also, please check this first: http://www.cmhc-schl.gc.ca/en/co/maho/gemare/gemare_011.cfm
