D.N.
Air duct cleaning is a waste of money for most people. The only time you really need it is if you first buy your home and have allergies and the previous owners had lost of pets or were smokers. The other time is if you complete a big renovation because all the dust in there. My neighbor's brother or in law used to work for a company that cleans them. Most of the time, the person could have saved a lot of money and just vacuumed them themselves. He said he had never seen one that was horrible. One was really dusty only because they had completed a full house renovation. You should be able to check them yourself by looking in the take in vents and the output vents in the ducts.