Did you know that cleaning your ducts and vents can help airflow and increase energy efficiency? According to the Environmental Protection Agency (EPA), keeping your air ducts and vents clear can increase energy efficiency and indoor air quality. While the cost to clean ducts and vents might sound high, the benefits to homeowners–especially those sensitive to allergens–is worth considering.

There are many interesting comments from several informed individuals. The question that has not been answered is how do duct systems get dusty and dirty? As a RESNET Home Energy Rater, I perform pressure tests on homes and duct systems, and the one common thread is . . . most air delivery sytems have large amounts of air leakage. The solution is to seal the duct system, and pay particular attention to the return duct system and ductwork near the air handler (the 'blower'). As others have said, a captive (sealed) duct system with proper filter maintenance should be more then adequate for most occupants. For those who have allergy, asthma, or other breathing problems, a filter with a higher MERV rating (number should be listed on the package) or a HEPA filter are good choices. These filters will capture smaller particulates and should improve the indoor air quality. Again, make certain that the entire duct system is sealed, preferably with mastic, second choice UL-181 foil tape - never use cloth duct (also known as duck) tape.
If you want to get some of the dust and debris out of your ventilation system, you can mix household cleaners like bleach with water, dip a cloth in the mix and then the wipe out the system. This will remove a layer of the spores, which could increase the quality of air a bit and help with the flow of air throughout the house until a pro can come out.
My best advice has always been that a proper duct cleaning is a valuable investment when moving into a home (new or old), after major renovations and if the ducts have never been cleaned before. It is unlikely that there will be increased air flow, as finding major blockage is unusual, but this will eliminate this as a possible concern if there are air flow concerns. It is also true that the "dust" that is cleared out will most likely never have been distributed through the house unless there has been some work done on the ducts. What is cleared out will be pet hair, toys, clothes, construction material, and biological material (small carcasses and/or feces). Once a proper cleaning is done a follow-up is rarely necessary, but up to the home owners discression.
You and your family spend hours sitting on your favorite chairs, couches and sectionals. Over time, dander and body oil become trapped in the upholstery, but with regular cleanings you can keep these delicate fabrics looking, feeling and smelling great. We examine your furniture and select the best process to safely clean and protect any kind of upholstery, including leather. 
I noticed a lot of negative feedback, though unfortunately there are many dishonest companies out there. I currently work with a company that cleans duct work and we DO NOT use any scare tactics or up sell services or equipment. Once every 10years of course there are exceptions. We clean supply, returns, air handler, housing, motor, and fan. Though be discerning when qualifying anyone to work in your home. I would ask for REAL REFERENCES to contact.

I know it has to have a new concentric venting system installed, I believe it needs new plenums ( mine are rusty but both of these require extra work , so someHVAC persons are saying I do not need either!! RED FLAG THERE. Also, it will need a new drain using PVCP ?? Piping run maybe two, depending on where my evep coil drain is conected (here in TN they use to run them in with the septic lines, now they cannot be run through that way), Lastly I am not where or what these things do beides hold water but I was told It needs a filter rack and new filter base safety pan. THATSSS it that is all I know about this stuff aside from the fact that nothing up there is to code thus far LOL. !!
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].
All these pro duct cleaners answer with "it's common sense, everything operates better when cleaner" etc. But your explanation is correct. Especially so with flex tube ducting where dust gets "stuck" between the lowest valleys (between wire coil supports) where air flow is drastically reduced -- which is more than 50 pct of the entire interior surface area of the flex ducting. That sounds like a bad thing but also has a good effect of trapping dust from escaping.
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.
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.
In addition, the black dust was found in most of the heat registers. He could rub it off on his fingers but did nothing but spray compressed air on it which didn’t make it disappear since it wasn’t loose. Also, in the register in the basement he described the black dust as being oily. The reality of that situation is that I had the AC on until the morning of the service and minutes after he snaked the hoses in my back door it started raining. The basement register had condensation from the humidity all over it. It was not oily but wet. He asked for an old towel and wiped it out. Never saw anything so black – because I never had to clean soot. That is what I have in my ducts. Soot from years of the old coal furnace.
Despite Bergendahl's experience, Vinick says NADCA's certification standards have improved the situation. "A lot of [service companies] weren't going about it the correct way," he says. “We have an anti-fraud task force, and we’ve gone after some fraudulent duct cleaners with the help of state attorneys general.” He suggests that in addition to NADCA membership, homeowners make sure their cleaners are an established business, have appropriate insurance and are registered to do business in their state and locality.
There is a lot of good, general information in the article. As with anything, the homeowner should do their due diligence in getting enough information to make an educated decision. Should duct-work be cleaned? YES! Does it need to be cleaned annually or even every second or third year? Not necessarily. It all depends on a bunch of variables. You're right that a well designed and balanced system will deliver the right amount of air flow, but sometimes conditions outside the home/business, make it a necessity to get the ducts cleaned. As for mold? NO filter is going to address a mold issue. If you have mold, you have a moisture issue that needs to be addressed. Also, in my 38 years of experience in the HVAC and sheet metal industries, washable filters are one of the reasons ducts need to be cleaned. They are no where near efficient in cleaning/filtering the air to the level that they should.
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.

In most modern homes with up-to-date heating and air conditioning systems, filters are changed regularly through the year, so you may not even need to hire a professional. However, keep your eyes open for the accumulation of dust, dirt, dander and mold. If you see it despite regularly changing your filters it could be an indication you need a high-pressure cleaning.
I recently replaced my 44 year old furnace. Over the years we have had several construction projects inside the home. For many years breathing the heated air from the duct work caused excessive sneezing, sinus issues, and lung irritation. . The heat smelled like dust. To maximize air quality I added a humidifier, MERV-11 filter, and UV light onto the new furnace. To further improve air quality, I had the ducts cleaned and sanitized. I took before and after pictures of the inside of each return and output duct. They were filthy before, and sparkling clean and fresh after the procedure. Now when running the system, clean sanitized air flows through my whole house. A huge difference. It will make sleeping and being indoors during the winter months far more tolerable. I use window air conditioners, and run the system in the summer to keep the house air clean and fresh on hot summer days too. It works! Great decision!
I noticed a lot of negative feedback, though unfortunately there are many dishonest companies out there. I currently work with a company that cleans duct work and we DO NOT use any scare tactics or up sell services or equipment. Once every 10years of course there are exceptions. We clean supply, returns, air handler, housing, motor, and fan. Though be discerning when qualifying anyone to work in your home. I would ask for REAL REFERENCES to contact.

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One of the best ways to ensure that the air in your home is clean is to clean your air vents. The air ducts in your house contain millions of particles of dust, hair, dirt, pollen, spider webs and other allergens [source: Alpine Air Duct]. Cleaning your air vents will also save you money on heating and air conditioning. So read the tips listed below and learn about how you can clean the air vents in your house.
When these aren't properly maintained and sanitized, they can build up dust, pollen, and even mold. This means when the air conditioner or heater turns on, the spores are released into the air for you to inhale. While some are less harmful, people who have allergies or sensitivity to certain spores will react negatively. Plus, mold is dangerous for anyone to ingest and should be avoided by regular maintenance.
I have lived in Calgary for quite some time now. When I first moved here I couldn’t stand the humidity levels. Its like a desert come winter. When I first moved into my new home, the house inspector insisted I have my furnace and ducts cleaned. I was very sceptical about duct cleaning to begin with. The company I hired came on time and were very respectable from the start. Before mentioning anything they asked me what my concerns were and what issues I was having. They were more concerned about addressing my issues then bringing anything non related up. I ended up going with this company and getting a humidifier installed a couple days later after the cleaning. Its been almost 4 years now that I have been here. The humidifier is working great and the difference is incredible. They took me around explained step by step what they were doing and the reasons they were doing it. With all those other companies out there, I am glad I found them at this site.
Good article, but it fails to point out that leaky return-side ducts could be drawing dust and allergens into the duct system from the enclosed spaces in which they run, e.g. between walls, below floors, attic. So duct cleaning may only be a temporary solution. The homeowner can get a home energy audit -- free in many states -- to determine if they have significant duct leakage. An Aeroseal dealer may be able to effectively seal up the duct system without needing to tear into walls etc to get to the ducts.
I am very interested by your post. We recently had a lead inspection on our property and one thing the lead inspector suggested was to get the air ducts cleaned out. We had our ducts cleaned last year after we under went a large renovation project (since we have a toddler in the house). This year we decided to go for lead compliance and had all our lead removed (we moved out for the work). Recently, my son had a false positive lead test, which prompted us to get a lead dust inspection around the house (including having the vents dust-wiped on the inside). The levels inside the ducts weren't crazy high (but more than would be acceptable for a floor). As it turned out my son's lead levels are very low (but not zero). Is it possible however that lead dust from the inside of a vent can come out? Would this be a scenario where you think air duct cleaning would be beneficial?
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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