Because research into air duct cleaning is still in its infancy, it is impossible to make a blanket advice. The US Environmental Protection Agency (EPA) recommends you to study this entire booklet since it contains vital information.

Duct cleaning has never been proven to prevent illness. Neither do studies convincingly show that filthy air ducts increase particle (e.g., dust) levels in dwellings. Rather, it sticks to the duct surfaces rather than entering the living environment. Remember that unclean air ducts are just one of many probable sources of particulates in homes. Pollutants enter the home from both outside and inside activities including cooking, cleaning, smoking, or just moving around. A small amount of household dust or other particulate matter in air ducts offers no health danger.

You should clean your home’s air ducts if:

  • Mold growth is apparent inside hard surface (e.g. sheet metal) ducts or on other HVAC components. Mold detection in heating and cooling systems has numerous crucial things to understand:
  • Many parts of your HVAC system may not be visible, so ask the technician to show you any mold they find.
  • Remember that while a substance may seem like mold, only an expert can determine if it is mold or not, and that ultimate confirmation may require laboratory testing. For around $50, several microbiology labs can determine if a sample on clear sticky household tape is mold or a material that resembles mold.
  • If your insulated air ducts get wet or moldy, they need to be removed and replaced.
  • Mold growth will return if the conditions that caused it are not rectified.

Vermin infested ducts, e.g. (rodents or insects).

Dust and filth clog ducts, or enter the home through supply registers.

If any of the above conditions exist, it usually means there are underlying causes. The problem must be rectified before cleaning, retrofitting, or replacing your ducts.

Cleaning heating and cooling system components (e.g., cooling coils, fans, and heat exchangers) may enhance efficiency, extend system life, and save energy and maintenance costs. However, there is minimal evidence that cleaning merely the ducts improves system efficiency.

You may think about cleaning your air ducts because they will grow dusty over time and should be cleaned periodically. No research suggests that good cleaning is harmful if done properly. The EPA advises simply cleaning the air ducts as needed. To avoid carbon monoxide poisoning, the EPA recommends having your furnace, stove, or fireplace examined and serviced annually.

You should adopt the same consumer care while evaluating a service provider’s competency and reliability.

Some air duct cleaning companies may advise you to use a chemical biocide within your ducts to destroy bacteria, fungi, and mold. They may also suggest using a “sealant” to prevent dust and grime from entering the air or to seal air leaks. Using chemical biocides or sealants should be permitted. It is unknown whether targeted chemical biocides and sealants are successful in duct cleaning and whether they are safe for usage. Read Should chemical biocides be applied within air ducts for more details.


Preventing water and dirt from entering the system is the most effective technique to prevent contamination.

What is Air Duct Cleaning?

Most individuals are now aware that indoor air pollution is an increasing concern. Many companies advertise products and services to improve indoor air quality. Your air ducts are undoubtedly dirty and need cleaning to improve your home’s indoor air quality.

These services normally cost between $450 and $1,000 per heating and cooling system, depending on:

  • the cleaning system’s size and accessibility 
  • climatic region 
  • pollution level
  • level of contamination
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.

Aside from heat exchangers, duct cleaning includes cleaning condensate drain pans and fan motors.

Incorrectly installed, maintained, and operated components might pollute with dust or pollen. Moisture encourages microbiological growth (mold) and spore discharge into the home. Certain pollutants can cause allergic responses or other symptoms. If you choose to have your HVAC system cleaned, make sure the professional is qualified to do so. Contamination of the entire system by one unclean component negates all benefits. Industry associations have defined standards for air duct cleaning. Before vacuuming ducts, a technician typically uses specialized tools to dislodge dirt and debris.

The technician may also recommend spraying chemical biocides to the ducting and other system components. Chemical treatments (seals or other encapsulants) can help prevent mold growth and dirt particle or fiber escape from air ducts and equipment housings. Educate yourself before letting biocides or chemical treatments in your air ducts. They should only be used after a thorough cleanse.

Sealing duct air leaks is not the same as encapsulating duct surfaces. Duct sealing saves energy.

Choosing To Have Your Air Ducts Cleaned

A/C duct cleaning has unknown benefits and drawbacks Cleaning your air ducts is important for your health, but it depends on your home. Until you have allergies, unexplained symptoms, or illnesses, cleaning your air ducts is usually unnecessary unless mold growth is evident or odorous. Vacuuming or cleaning the registers indicates clean air ducts.

If you or a family member gets weird or unexplained symptoms, see your doctor. Below are materials from the EPA to assist identify and address indoor air quality issues.

Your air ducts may need cleaning as dust accumulates over time. Regular duct cleaning is not risky if done properly.

Incorrect duct cleaning may result in poor indoor air quality. Useless vacuum collectors can emit more pollutants than leaving ducts alone. Poor workmanship can damage ductwork and HVAC systems, necessitating costly repairs or replacements.

  • You should clean your home’s air ducts if:


-Mold growth is apparent inside hard surface (e.g. sheet metal) ducts or on other HVAC components. Mold detection in heating and cooling systems has numerous crucial things to understand:


-Many parts of your HVAC system may not be visible, so ask the technician to show you any mold they find.


-Remember that while a substance may seem like mold, only an expert can determine if it is mold or not, and that ultimate confirmation may require laboratory testing. For around $50, several microbiology labs can determine if a sample on clear sticky household tape is mold or a material that resembles mold.


-If your insulated air ducts get wet or moldy, they need to be removed and replaced.


-Mold growth will return if the conditions that caused it are not rectified.


Ducts are infested with vermin (rodents or insects) 

Air Ducts are clogged with enormous amounts of particles that are released into the residence from supply registers.

Other Vital Points

No proof that duct cleaning prevents sickness. Neither unclean air ducts nor cleaning them has been proven to increase particle levels in dwellings. Soot accumulates on the surfaces of air ducts and doesn’t get into the living room. Particulate sources in homes include filthy air ducts. Pollutants enter the home from outside and inside sources like cooking, cleaning, smoking, and walking. In addition, there is no proof that a little amount of dust in air ducts is damaging to health.


Duct cleaning is not recommended because its benefits are debated. Annual furnace, stove, or fireplace maintenance helps prevent CO poisoning. Disinfecting clogged cooling coils, fans, and heat exchangers may improve system efficiency. However, cleaning your ducts has no proof of increasing system efficiency.

Choosing a Duct Cleaning Service

Check your Yellow Pages under “duct cleaning” or contact the American Air Ducts at the  phone number shown at the conclusion of this article. Ensure your air duct cleaning Houston tx service provider is experienced and trustworthy. Request written quotations from at least three providers before cleaning your ducts. Ask the service providers to show you the contamination that warrants cleaning your ducts.

Do not engage duct cleaners who make dubious health claims. Do not engage duct cleaners who advocate duct cleaning as part of regular HVAC maintenance. Be aware of duct cleaners who claim to be EPA certified. To be clear, EPA neither sets nor certifies duct cleaning standards or companies.

Do not use chemical biocides or treatments unless you fully grasp the benefits and drawbacks.

Verify references to ensure previous customers were satisfied and had no issues with their HVAC systems following cleaning.

Contact your county or city’s consumer affairs office or the Better Business Bureau to see whether any of the businesses you’re considering have been sued.


If you want to hire a service provider, American Air Duct cleaners have worked on systems like yours; They will take precautions to keep you, your pets, and your home safe.

You can use them to clean air ducts and, if you have fiberglass duct board or a fiberglass duct liner, they fulfill NAIMAEXITEXIT EPA WEBSITE guidelines.

Inquire about the service provider’s state licensing. Arizona, Arkansas, California, Florida, Georgia, Michigan, and Texas required specific permits for air duct cleaners as of 1996. Other states may follow suit.

If the service provider charges by the hour, ask for an estimate of the job’s duration and whether there will be any delays. Be sure to get a signed contract describing the total cost and scope of the job before the duct cleaner starts working.

Expectations From an Air Duct Cleaning Service

If you hire someone to clean your ducts, they should:

  • Open access ports or doors to clean and inspect the entire system.
  • Before cleaning, check for asbestos-containing items (insulation, register boots, etc.). Professionals only should disturb or remove asbestos-containing materials.
  • Use only high-efficiency particle air (HEPA) vacuuming equipment if the vacuum exhausts within the dwelling.
  • During cleaning, protect carpets and furniture.
  • Surfaces of ducts can be cleaned carefully with a contact vacuum.
  • Only use soft-bristled brushes on fiberglass duct board and fiberglass-lined sheet metal ducts. (While soft-bristled brushes can clean flex ducts, it is often cheaper to simply replace them.)
  • Protect the ductwork by sealing and re-insulating any access holes made or used by the service provider.

Determining the Duct Cleaner’s Work

A visual check is the best approach to ensure your HVAC system is clean. Some companies utilize remote imaging to inspect ducts. The entire system should be visible clean; no debris should be visible to the human eye. Pre-show the Post-Cleaning Consumer Checklist to the service provider. Ask the service provider to show you your system when it is installed.

  • If you answer “No” to any of the checklist’s questions, there may be an employment issue. Ask your service provider to fix any issues until you can cross off the checklist.

Preventing Duct Contamination


A solid preventive maintenance program is vital to minimize duct contamination whether you choose to have your home’s air ducts cleaned or not.

To keep dirt out of the system:

  • Use the highest efficiency air filter recommended by your HVAC manufacturer.
  • Alternate filters.
  • To clear your filters, replace them more frequently.
  • Check for missing filters and gaps around the filter holder.
  • When having your heating and cooling system serviced, ask the technician to clean the cooling coils and drain pans.
  • Don’t use the HVAC system until the dust is cleared up.
  • Vacuum your home regularly. (Use a HEPA vacuum or the highest efficiency filter bags your vacuum can carry. Vacuuming can raise dust in the air, as well as in your ducts.
  • If your heating system includes in-duct humidification, follow the manufacturer’s instructions for operation and maintenance.

A proper preventive maintenance program is vital whether or not you choose to have your air ducts cleaned.

To keep ducts dry:

  • Ducts should be dry. Moisture control is the best technique to avoid biological growth in air ducts.


  • Defective installation or maintenance might allow moisture into the duct system. Condensation on or around cooling coils causes moisture contamination of air conditioning systems (when a surface temperature is lower than the dew point temperature of the surrounding air). Condensation or high relative humidity indicate the potential for mold growth on any duct. Controlling moisture isn’t always easy, but here are some tips:

Repair any leaks or water damage promptly.

Keep an eye on the cooling coils, which should remove moisture from the air but might instead cause mold growth. Check condensate pan drainage. Stagnant water and/or debris suggest a major situation that necess Test wet insulation near cooling coils.

Non-conditioned ducts must be sealed and insulated (e.g., attics and crawl spaces). This will help keep moisture out of the system and help it perform correctly. A properly insulated HVAC system prevents water condensation.

Replace your air conditioner and seal any ducts if necessary. An inefficient large unit, especially in humid situations, will cycle on and off repeatedly. Test your new system’s condensation management.

Problems with Duct Cleaning

Is duct cleaning safe for health?


  • In short, no one knows. Some ducts are heavily polluted with hazardous substances. The duct system can help spread toxins throughout a home. This is why duct cleaning makes sense. A small quantity of dust in your air ducts is normal. Not all heating and cooling systems require duct cleaning, which also includes drain pan cleaning, filter changes, and periodic inspections of heating equipment. The benefits of air duct cleaning are still being studied.



  • Request information from any or all of the sources indicated at the conclusion of this book and ask questions to possible service providers.

What makes ducts susceptible to mold and other biological contaminants?

You may be familiar with sheet metal air ducts. Modern residential air duct systems are frequently built of fiberglass duct board. Commonly composed of metal with a fiberglass interior. Flexible duct, usually lined with plastic or another material, has become increasingly popular since the early 1970s.


As a result of:

  • better temperature control
  • energy saving
  • lowered condens


Internal insulation enhances acoustics. Years of use of insulated duct systems without mold development Keep them clean and dry. Debate rages over whether porous insulation (like fiberglass) is more prone to contamination than bare sheet metal ducts. Internally lined sheet metal ducts produce bacteria at the same pace as unlined sheet metal ducts as long as dirt and moisture enter into the duct system. Mold on bare sheet metal is much easier to remove. The EPA has approved biocide cleaning. Cleaning mold-infested porous duct materials does not prevent regrowth, and no EPA-registered biocides exist. The EPA, NADCAEXITEXIT, and NAIMAEXITEXIT all advocate replacing wet fiberglass duct material.

In The MeanTime

Experts believe that if moisture and dirt are present in ducts, the potential for biological pollutants to thrive and spread throughout the home exists. To avoid biological growth in all types of air ducts, control moisture.

  • Fix any leaks or standing water.
  • Drain pans should slope toward the drain to remove standing water under cooling coils.
  • Humidifiers must be properly cared for.
  • Maintenance personnel should have direct access to heat exchange components and drain pans for thorough cleaning and maintenance.
  • A trained heating and cooling system contractor should remove and replace any wet or moldy insulating material.
  • No steam cleaning or other moist treatments on ductwork.

Should air ducts have chemical biocides?


Some air duct cleaning services may advise applying a chemical biocide to your ducts to kill bacteria and fungi and prevent future growth. Some duct cleaning companies use ozone to destroy biological impurities. Ozone is a highly reactive gas classified as a lung irritant. However, there is still a lot of debate about whether or not adding chemical biocides or ozone to the ductwork is a good idea.


Problems with biocide and ozone in air ducts include:


  • Most biocides and ozone have not been studied in ducts. It is possible to introduce these compounds into the system by simply spraying or otherwise introducing them.


  • Some persons may be allergic to biocide or ozone, producing health issues.


Federal pesticide law governs it. An EPA-registered product has a limited use. The pesticide (biocide) label must state the intended application (s). Illegally using pesticides is against the law.

Raw sheet metal air ducts are now scarce. Clean exposed sheet metal ducting and rough surfaces. Unlined ducts allow some but not all of these. If the instructions say to rinse, do so at your own risk.

They are all approved for use on bare sheet metal ducting. Be sure your system has fiberglass duct board or fiberglass walled ducts before spraying biocide.

For The Time Being


Before using a chemical biocide in your ductwork, a service provider should:


  • Show obvious microbial growth in your ductwork. Some firms will claim that growing microorganisms on a settling plate has contaminated your air ducts (i.e., petri dish). This isn’t right. In the air are some bacteria that grow on settling plates. People sometimes need to do tests in the lab to be sure that a chemical is a living thing. Other approaches are unreliable.


  • Justify why regulating moisture cannot erase biological growth and prevent subsequent growth.

To utilize a biocide, the service provider must:

  • Show you the biocide’s label, which will list its permitted uses.
  • Apply biocide solely to un-insulated portions of the duct system after cleaning to inhibit mold re-growth.
  • Always follow the product’s label directions.

You may want to leave the area when low-toxicity products are provided for your own safety.

Do sealants keep dust and debris out of the air?

Manufacturers of coating and encapsulating duct surfaces claim their treatments prevent dust and dirt particles from entering the air. Sealants, like biocides, are regularly sprayed into working ducts. In tests, the materials do not completely coat the duct surface. Sealants can alter the acoustical (noise) and fire retardant properties of fiber glass lined or built ducts, voiding manufacturer’s warranties.

Sealants’ safety, effectiveness, and general desirability remain under doubt.

The toxicity of these commodities in normal usage or in a fire is unknown.

Sealants haven’t been evaluated for duct air breakdown.

For Now

Most duct cleaning organizations, including SMACNA and the EPA, do not encourage routinely use sealants to encapsulate impurities in any type of duct. For damaged fiberglass insulation or fire damage, sealants can encase duct surfaces. Sealants should only be used after a thorough duct cleaning.


If you’re unsure about duct cleaning this HVAC business may be able to help. 

If you want more insight on If Cleaning Ducts Helps With Dust, talk to an American Air Duct cleaning  professional at (866) 373-3828

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