http://ezinearticles.com/?Air-Conditioner-Duct-Cleaning---Rotobrush-Business-Opportunity&id=5795186 Air conditioner duct cleaning when combined with cleaning coils, is said to improve energy efficiency by 30 percent. If you clean the clothes dryer vent and remove blockages during the same service call, you can eliminate a fire hazard and cut the time necessary to dry clothes as well. Rotobrush duct cleaning machines operators can earn significant income even part time. What else will you need to know to evaluate the benefits of central air duct cleaning?