The cooling coils the air comes into contact with appear to need UV-C lights on them in humid climates. That's the biggest thing. If the ducts have never been cleaned, then getting that done goes without saying. But those coils need to be cleaned, disinfected, and then UV-C light(s) installed to prevent mold & bacteria build-up in the future on them. That appears to be chiefly responsible for the dirty laundry and/or sour milk smell coming from forced-air AC systems in humid regions.


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?
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.
Before you choose any duct cleaning service provider, interview as many service providers as you can. Ensure that the service provider is certified by the National Air Duct Cleaners Association or NADCA. Make sure that they hold a good standing in the Better Business Bureau and have all the necessary certifications and license. Be clear about their terms of service. Make sure they have the right equipment to do the job. It is best to go for a company that has been tried and tested successfully by any of your acquaintances or opt for a service provider that has been in the business for quite some time.
The answer to your question is most likely "Yes," but not defiitely. It depends on where the dust is coming from. Now, if your house is more than say, 12 years old then you likely do have leaks in your ducts that can let in insulation particles and dust from your attic. If this is the case then cleaning of the ducts-PROPER CLEANING, which like the article sas doess include EVERYTHING that the conditioned air passes through, such as your indoor evaporator coil and blower housing assembly-is definitely a good first step to getting that dust under control! Of course I highly recommend that you also have your ducts SEALED as well, or else you will have to repeat the cleaning some time down the line. As a 3rd step, consider an electronic air filter. I always thought they were a scam, personally, so I never bothered selling them to my clients. Then one day my manager sent me to install one for a senior couple in a mobile home. The wife had bad allergies, and her eyes were constantly watering and puffy and red. Well, I did a quality check 60 days later and she could not stop praising that air filter! Keep in mind that in a mobile home, duct seals are not as complete as those in other homes due to access issues.
My 48 yr old house (mine for the last 4 yrs) has considerable dust in the return plenum (fiber duct). I’m remodeling and recently re-sealed the return plenum AND the site-fabbed transition built when the new unit was installed, 2013. The return was leaky no doubt drawing musty, dusty air from the crawl space due to the Red-Neck fab & seal job! Pitiful craftsmanship! It took me 7 hours to fix the new transition piece. Anyway, the dust in the house is the same “color” as whats in the return duct and I’m getting way too much & too often in the house. I’ve also cleaned my coils, which were not that dirty.
The most effective way to clean air ducts and ventilation systems is to employ Source Removal methods of cleaning. This requires a contractor to place the system under negative pressure, through the use of a specialized, powerful vacuum. While the vacuum draws air through the system, devices are inserted into the ducts to dislodge any debris that might be stuck to interior surfaces. The debris can then travel down the ducts to the vacuum, which removes it from the system and the home.
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If not properly installed, maintained and operated, these components may become contaminated with particles of dust, pollen or other debris. If moisture is present, the potential for microbiological growth (e.g., mold) is increased and spores from such growth may be released into the home's living space. Some of these contaminants may cause allergic reactions or other symptoms in people if they are exposed to them. If you decide to have your heating and cooling system cleaned, it is important to make sure the service provider agrees to clean all components of the system and is qualified to do so. Failure to clean a component of a contaminated system can result in re-contamination of the entire system, thus negating any potential benefits. Methods of duct cleaning vary, although standards have been established by industry associations concerned with air duct cleaning. Typically, a service provider will use specialized tools to dislodge dirt and other debris in ducts, then vacuum them out with a high-powered vacuum cleaner.
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