On the other hand there are many more air duct cleaning companies that will properly clean the air system and air ducts and use commercial negative air duct cleaning vacuums with at least 2,000 CFMs of vacuum power and utilize proper agitating tools to move the contaminates within the duct work to be captured with HEPA filters and contained by the air duct cleaning vacuum equipment.
A. First of all, be sure to be there when they do the job! We had our ducts cleaned and got robbed by one of the workers who thought we wouldn't miss a few "minor" personal items. But, even though they didn't believe us at first, we reported it to the police and the company and he got caught! Secondly, ask if they not only remove the vent covers but clean those too. Ask how they clean them and if they use their own cleaning supplies and take the vent covers outside to clean--not in your bathroom or kitchen sinks, using your personal towels. Ask if they clean up the lint that falls into the room with a vacuum cleaner. They should have a crew of at least two people to put the hose in and clean out the vents and one to clean the vent covers and the area around the vents where the lint falls. They should clean the air intake vents and cover also. Some try to sell you on cleaning out your actual AC/HVAC unit coils. I don't see the need for that, but if they insists it is needed, get them to show you the dirt in there that they will be cleaning out. If they can't show you, chances are they will not be able to get in there to clean it. They should change the air filter, but be sure they don't try to sell you some heavy-duty, life-time guarantee filter that supposedly never needs to be replaced. Those don't let enough air flow through. The medium grade ones changed every few months or so work the best. You can buy those at a home improvement store and change them out yourself during the year. Make sure that they don't damage your walls with their big machine, trying to get it down the hall and around corners. They damaged our walls, too and we had to have them plaster and paint it again. Just because the company has a nationally recognizeable name doesn't mean they will do the best job. Often these are owners who hire flunkies to do the work who are thieves and don't care. It would be better to get a local guy that has been doing it a long time and can furnish you with references of satisfied customers.
These are companies who are more interested in getting your money, through misleading advertisements or “bait and switch” mailers than actually doing the work properly and improving your indoor air. The very worse thing you can do is to hire a company that may actually create more of an indoor air problem for you and your family due to improper cleaning or use of inferior air duct cleaning vacuums with no more vacuum power than a large Wet/Dry vacuum with a rotating brush attached at the end of the hose, or use a “carpet cleaner” who is not properly licensed or certified to clean air systems. Be especially suspicious of companies advertising low one price duct cleaning service, it’s like providing a one price to paint the exterior of your home whether it be 1 story or several stories high.
Of the cleaning services in which we are proud to be specialists, air duct cleaning is by far the one that requires the most trust between the consumer and the air duct cleaning service provider. There are many unscrupulous air duct cleaning companies purporting to be something they are not, many advertisements using unrealistic scare tactics, and of course bait and switch tactics are prevalent in the industry. You need to feel confident in the professionalism of the firm you hire to clean your air ducts because you are asking someone to clean the inside of your duct work, where it can be difficult to see the results of the job.