We looked into dryer/air duct cleaning. Never went forward with it. Already got enough services on our plate that I am not marketing properly enough. There are some good portable units out there if you have room in your van and it appears to be an easy add on sale since we’re already in the home. May want to check around and see if there are any attachments you could attach to the end of your u-mate/ninja to cut costs. Don’t know if we run a large enough hose though, even for just a dryer vent, plus we probably don’t have the proper recovery tank set up. Definitely couldn’t use any of our current machines to do ducts due to size of objects in many vents (dead mice, 2×4’s, McDonalds bags, etc.) We have a local company I recommend to my customers that all they do is air duct/dryer vent cleaning. No carpet cleaning so not my competition.