How exactly do you expect to kill or remove mold without it ? You can’t even clean your hvac systems coils without moisture of some type ,if you use a steam cleaner you can literally clean the whole system minus the electronics . You should do more research and possibly talk to people who do the work before posting , but don’t listen to me i only have a class A contractor license ,epa license , install /repair hvacs , rent and flip houses for a living .
How often you should clean your air ducts depends on your situation. If you or someone in the home has asthma or is acutely allergic to certain airborne materials or pollen, regular duct cleaning may be helpful. The Environmental Protection Agency doesn’t have an official position on the necessity of air duct cleaning unless the ducts have been contaminated by rodents, insects or mold, or you are aware of particles blowing out through the vents. The EPA recommends you have your air ducts cleaned on an as-needed basis. The National Air Duct Cleaners Association (NADCA) suggests having air ducts cleaned every three to five years.
I just had my blower module replaced because my AC coil was frozen over. The underside of my coils had a thick mat of dust because I had never had it cleaned. I cleaned it myself by using a soft brush attachement on a shop vac. The inside of the blower appears to have a white/green growth, and I am sure the ductwork of my 30 year old house can’t be in good condition.

So I purchased a Groupon to have this service done on my HVAC. I waited like 3 weeks or so since I was not using the heat or AC and I was in no hurry. So, on the day of my scheduled appointment which was 12noon I get a call from their office at 12:05pm that they are running late and they are 2 hours away...How did they manage to end up 2 hours from my house? Odd. Anyway, the girl tells me that they can't make the appointment today and will have to reschedule 30 days from now. What? 30 days from now? I was expecting perhaps tomorrow or the next day, not 30 days from now. This is extremely poor customer service and poor time management. Their leadership team should be reprimanded or replaced. I don't know how this company can stay in business when their business practices are so disorganized and they cannot even manage a schedule efficiently. I would NEVER recommend this company when they treat the customers so poorly. Their front office person should be retrained or fired since she does not have the skills needed to deal with customers. I would go so far as to fire their Office Manager or perhaps the Manager of this company. Well, at least they did not show up and provide poor service as it appears they did in the other customer reviews.
Concealed behind your walls and mostly ignored, your air ducts serve as vital pathways that deliver warm and cool air throughout your home. While they may be unseen, your air ducts are working whenever you have your air conditioner or furnace running–nearly year round. Attached to your HVAC, air ducts transfer the air from these systems throughout your home. What many homeowners don't realize is that your air ducts, in nearly constant use, continually accumulate dust, grime, debris, pet dander, and allergens throughout the year. A professional air duct cleaning is necessary for better indoor air quality and the health of your family.
Air duct cleaning companies are responsible for eliminating dust and other potentially harmful elements that can build up inside the air ducts of your home's cooling or heating system. If you need your air ducts cleaned, you may want to seek an air duct cleaning company that has specific knowledge, qualifications, and experience to ensure your home is properly cleaned and left uncontaminated. This article provides details on how to best choose an air duct cleaning company.
I bought a Groupon for an air duct cleaning and deodorizing for $59.  I read all of the fine print and it said "unlimited ducts."  When they came to perform the service they said it would cost an additional $200 to cover the entire house.  I ended up canceling the whole service and the guy who was there do to the work said he is leaving the company because of issues like this.  He said 25% of their customers end up canceling when they arrive to do the service because of the dishonest advertising.  Later the same day, the manager called me to discuss why I canceled the service.  I told her the Groupon was dishonest and intentionally misleading and her response was, "I don't work on the advertising."  I told her that as the manager she has some responsibility for what is advertised about the company and she said, "I just work here, I don't own the company."  So apparently the management has no responsibilities at Best Air DC, perhaps that is part of the problem.  I will never use them again and hope no one else does either.  Save your money!
Here in Frisco, TX…just had a tech come out to clean vents. I used a 30 bucks groupon for “complete vent cleaning”. He told me I have 3 AC units and groupon covers only 1. I told him to do the unit upstairs where the kids sleep. He decided on his own to do the downstairs unit. I yelled at him why he is not doing the unit I told him to do! He said they are all connected. I will clean two for you for the price of one… Oh really?

Moisture can enter the duct system through leaks or if the system has been improperly installed or serviced. Research suggests that condensation (which occurs when a surface temperature is lower than the dew point temperature of the surrounding air) on or near cooling coils of air conditioning units is a major factor in moisture contamination of the system. The presence of condensation or high relative humidity is an important indicator of the potential for mold growth on any type of duct. Controlling moisture can often be difficult, but here are some steps you can take:
How often you should clean your air ducts depends on your situation. If you or someone in the home has asthma or is acutely allergic to certain airborne materials or pollen, regular duct cleaning may be helpful. The Environmental Protection Agency doesn’t have an official position on the necessity of air duct cleaning unless the ducts have been contaminated by rodents, insects or mold, or you are aware of particles blowing out through the vents. The EPA recommends you have your air ducts cleaned on an as-needed basis. The National Air Duct Cleaners Association (NADCA) suggests having air ducts cleaned every three to five years.

Duct cleaning is a complete scam, I was a “duct cleaning technician” for a whole week before I was fired for not upselling elderly widowed women $2000 extra for “toxic mold remediation” when their ducts were spotless to begin with. The last two days I was employed there I worked as a “helper” alongside a technician thats been with the company 7 years. He scammed every customer on mold and would at times get as much as $2500 extra for treating “toxic mold” in a typical 3 bedroom house in the suburbs. Wait…it gets even better, the “Biocide” the company used was simply a cheap $4.99 per gallon bought at Home Depot air freshener with no anti-microbial properties that was fogged into the HVAC system for 5 minutes, maybe using 1/2 cup of the stuff. In order to provide the customer with evidence of “mold infestation” the technician would be given bogus mold tests that always resulted in “toxic spores present” regardless if you swabbed the actual duct or nothing at all. Not to mention the actual duct cleaning job (typically $400) did basically nothing and the homeowner could’ve done a better job with a shopvac
Air duct cleaning service providers may tell you that they need to apply chemical biocide to the inside of your ducts as a means to kill bacteria (germs) and fungi (mold) and prevent future biological growth. They may also propose the application of a "sealant" to prevent dust and dirt particles from being released into the air or to seal air leaks. You should fully understand the pros and cons of permitting application of chemical biocides or sealants. While the targeted use of chemical biocides and sealants may be appropriate under specific circumstances, research has not demonstrated their effectiveness in duct cleaning or their potential adverse health effects. No chemical biocides are currently registered by EPA for use in internally-insulated air duct systems (see Should chemical biocides be applied to the inside of air ducts?).
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