Equipment used to clean ducts varies widely. The cheaper the equipment used the more you are just wasting money. This is why it's typically not worth doing. In some situations it may be beneficial, but only after determining and investigating the duct system. This should be done by a licensed HVAC contractor and not a duct cleaner that typically do not hold and HVAC license. (Duct cleaners aren't required to be licensed in HVAC in many areas.)
Pay particular attention to cooling coils, which are designed to remove water from the air and can be a major source of moisture contamination of the system that can lead to mold growth. Make sure the condensate pan drains properly. The presence of substantial standing water and/or debris indicates a problem requiring immediate attention. Check any insulation near cooling coils for wet spots.
He proceeded to clean each heat register by removing the grille and blasting it with an air pressure hose toward the duct opening thinking that the dust would magically be sucked inside. In one room this caused a ceiling smoke detector to go off because the excess dust fooled it into thinking there was smoke. I put my hand in front of a register he wasn’t working on and could hardly feel a suction. Although we discussed how I open and close damper doors, I realized later that he never checked, opened or adjusted them during the cleaning. He could have closed all but the one he was working on in order to increase suction results. His next step was to blast air into the duct and then attach a “squid-like” device that slapped around inside the duct as far as he could reach. This is important! In a newer house, ducts have long straight runs from the furnace. In older houses like mine they can turn and twist. In fact, the duct we have a problem with runs straight up from the basement inside a wall and turns 90 degrees into a soffit for three feet then into two 90 degree turns to get into the floor joist area for another two feet and finally a 90 degree turn up to the second floor register. When he cleaned this one he could only get three feet into the register with the hose or squid because of the turns. That was the case with most. Hardly what could be described as a decent cleaning.

I live in a 1950's ranch house in the South. The prior owners were smokers. Based on recommendations from one of the local conservation organizations, I decided to have a home energy audit done. As part of their findings, they recommended additional insulation in the attic and duct cleaning and sealing. This turned out to be a very problematic process. In terms of the ducts, it was necessary to remove the metal grates. However, these grates had been painted over many times and shoe molding covered the bottom of the grates. The vendor was not able to remove the grates without damaging them in the process. Because these grates dated back to the 1950's, it was difficult to find appropriate replacements. The ones I finally discovered were correct except they were 1/4" wider. This meant that the shoe molding had to be carved out. The duct cleaner could not provide any assistance with this problem. It took me a month of long evenings replacing the vent covers myself, carefully chiseling out the shoe molding and repainting. In terms of the extra installation in the attic, the same vendor used blow in insulation. Unfortunately, they did not recognize that the 13 floodlights whose mounting extended into the attic were not designed to be buried under insulation. The problem manifested itself in terms of expensive flood light bulbs failing continually. So, I had to have all of the light housings replaced. Yet another unexpected expense. Despite the expense, pain and suffering, I cannot report any improvement in my heating costs or the "quality" of the air. To be fair, I do not have any allergies and did not undertake this for air quality improvements but rather heating efficiency improvements.
Duct cleaning generally refers to the cleaning of various heating and cooling system components of forced air systems, including the supply and return air ducts and registers, grilles and diffusers, heat exchangers heating and cooling coils, condensate drain pans (drip pans), fan motor and fan housing, and the air handling unit housing (See diagram).
I am a service technician [since '92].....and as to double filtering.....I have never recommended it. Granted.....it would be noticeably helpful if the fiberglass filters are the main ones used [which I also never recommend.....as long as system can deliver appropriate air flow with a pleated cotton filter...and any decent service tech can check the air flow for proper cfm]. Any particles small enough to pass through a pleated cotton filter are going to pass through a second filter as well....unless the second filters are so tight that the system is starving for air flow. Has anybody ever accidentally put two filters in their automatic drip coffee maker? What if cars used two fuel filters or air filters? I have told some homeowners to try using second filters at each register [the black thin filter material cut-to-fit....same type used in many window air conditioners].....but I only suggest this when I know they will still get at least 400 cfm per ton of air flow [350 absolute minimum]......as some homeowners know others who say it has helped and it gives them a peace of mind knowing they are doing something to help contribute to a solution, so it HAS to help [even though I think it falls in the "one-born-every-minute" category.....similar to duct cleaning].

I purchased a Groupon for cleaning of unlimited air ducts and one return vent for $39. I should have checked into their hours first because they only offer services during normal business hours. So, with no evenings or weekends available you have to take time off work. I asked Groupon for a refund when I realized this and they refused because it wasn’t within the three day window. Then they didn’t even show up or call for the appointment. I called them after they were an hour late and they were going to call the local dispatch office and have them call me back within 15 minutes. I did not receive that call. I called again and was told I would get a call back from a manager. That didn’t happen either. So I asked Groupon for a refund again and they gave me Groupon bucks. When the survey came asking if I was satisfied with the Groupon customer service I said no, I want real money. I got my real refund the next day. Seems to me Groupon should stop dealing with these companies.


Very interesting article. I searched articles about services for cleaning ventilation systems. But I have some questions. For cleaning ventilation system used special products for cleaning. Can I know in company manager about, which type of cleaning products they use? Your family members may be allergic in some components. It’s very big problem. And one more problem it’s how to choose the right company in Internet. Sometimes I don’t have much time to find a company in my town and I use the Internet. But I find a lot of company. It is very popular services, for example, Stanley Steemer – https://www.stanleysteemer.com/ or my local not very popular service, for example, AllstatesAirDuctPro – http://allstatesairductpro.us/. Can I understand the company is professional or not, only looking through the website? What must I check on the website? Who has helpful information? I will very grateful for your help. Links I add for understanding my problem. They are random and not for advertising.

WELL, this summer when I opened them up we had black dust spewing from one of the upstairs vents. It resembled the fuzz that comes off new towels. This prompted us to look into duct cleaning. We heard from someone who had it done several times, said it was worthwhile, and knew of a firm that did a good job. Clean Air America sent a single technician for the appointment and after counting registers and ducts gave me a price of $360.00 which included “sanitizing” the system (a $99 additional fee per can used). The small size of the plenum forced him to connect the 8” round vacuum hose from the truck to the 10” square opening from our humidifier unit. In hindsight, a mistake since it reduced the “negative” pressure in the system.
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The bottom line is: no one knows. There are examples of ducts that have become badly contaminated with a variety of materials that may pose risks to your health. The duct system can serve as a means to distribute these contaminants throughout a home. In these cases, duct cleaning may make sense. However, a light amount of household dust in your air ducts is normal. Duct cleaning is not considered to be a necessary part of yearly maintenance of your heating and cooling system, which consists of regular cleaning of drain pans and heating and cooling coils, regular filter changes and yearly inspections of heating equipment. Research continues in an effort to evaluate the potential benefits of air duct cleaning.
I always get a laugh at anyone claiming to be in the business for any length of time that doesnt understand the importance of cleaning out a ventilation system. Not only for better indoor air quality but for maintaining your heating equipment. I guess it makes more sense to some people that the furnace will just run better with a ton of dust and debris and maybe this wont be a big cause of sytem breakdown and malfunction. I mean really? Maybe this guy got a bad company and or cleaning and is a little jaded but to advise cleaning your grills , which does nothing, and replacing a filter....come on guy.
What if you move into a 20 year old house and find that the people who owned it previously NEVER replaced the filter? It was so dirty that the HVAC system did not work at all. For most people - duct cleaning is NOT a waste of time or money. You must not have allergies. I have very bad ones plus asthma. It makes it very hard for me if I don't get it done every few years. By the way - the ducts get dusty just sitting there - especially without air going through them. Dust settles on them just like it does the furniture.
Very interesting article. I searched articles about services for cleaning ventilation systems. But I have some questions. For cleaning ventilation system used special products for cleaning. Can I know in company manager about, which type of cleaning products they use? Your family members may be allergic in some components. It’s very big problem. And one more problem it’s how to choose the right company in Internet. Sometimes I don’t have much time to find a company in my town and I use the Internet. But I find a lot of company. It is very popular services, for example, Stanley Steemer – https://www.stanleysteemer.com/ or my local not very popular service, for example, AllstatesAirDuctPro – http://allstatesairductpro.us/. Can I understand the company is professional or not, only looking through the website? What must I check on the website? Who has helpful information? I will very grateful for your help. Links I add for understanding my problem. They are random and not for advertising.

One of the best ways to know if your ducts or vents need to be cleaned is to just check them. Your eyes will be able to check for indications of mold, dust or pollen buildup. You might also be able to smell the presence of mold, which would be a clear indicator. Ductwork will have some buildup of dust, since the return registrars pull air back in. However, this doesn't mean your ducts have too much debris, and you can easily clean them with a duster or vacuum.

The fact is if they are dirty why not clean them. As for the Dr’s comment about if it is not disrupted it is fine. As a pet owner sometimes un disrupted pet hair will sit in the corner of a room or under a counter un disrupted but I still clean it when I notice it. Just because you cant see it doesn’t mean you should leave it there to collect more and more. The people that don’t want there air ducts clean either simply cant afford it but would like it done. OR! the crowd that are to cheap.. You should Clean all portions of your house.
A thorough visual inspection is the best way to verify the cleanliness of your heating and cooling system. Some service providers use remote photography to document conditions inside ducts. All portions of the system should be visibly clean; you should not be able to detect any debris with the naked eye. Show the Post-Cleaning Consumer Checklist to the service provider before the work begins. After completing the job, ask the service provider to show you each component of your system to verify that the job was performed satisfactorily.
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