My allergies flared up big time and i needed my ducts, furnace and dryer vent cleaned ASAP. I used Ozone in the past and I also called a top rated competitor. Ozone adjusted their schedule and came the next day. A top rated competitor told it would take them 40 minutes. I was surprised that Ozone took 3 hours. When I inquired as to difference in service time, Ozone sucks out the ducts whereas the competition uses air push everything through the vents into your furnace and then then just vacuum it out. Ozone and the top rated competitor charged the same amount. I think Ozone's method is much more thorough. The sweetest thing is I have a sixth month old and they came during her afternoon nap and were kind enough to maneuver, so as not to wake her. I highly recommend them!