| |
Indoor Environments Division (6609J)
Office of Air and Radiation (OAR)
EPA-402-K-97-002, October 1997
What Is Air Duct Cleaning?
Deciding Whether or
Not to Have Your Air Ducts Cleaned
Suggestions for
Choosing a Duct Cleaning Service Provider
What
to Expect of an Air Duct Cleaning Service Provider
How
to Determine if the Duct Cleaner Did a Thorough Job
How to Prevent Duct
Contamination
Unresolved Issues of
Duct Cleaning
To Learn More About
Indoor Air Quality and Air Duct Cleaning
Consumer Checklist
A Typical Residential Heating and Cooling System
Most people are now aware that indoor air pollution is an
issue of growing concern and increased visibility. Many companies are
marketing products and services intended to improve the quality of your
indoor air. You have probably seen an advertisement, received a coupon
in the mail, or been approached directly by a company offering to clean
your air ducts as a means of improving your home's indoor air quality.
These services typically -- but not always -- range in cost from $450 to
$1,000 per heating and cooling system, depending on the services
offered, the size of the system to be cleaned, system accessibility,
climatic region, and level of contamination.
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).
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.
In addition, the service provider may propose applying chemical
biocides, designed to kill microbiological contaminants, to the inside
of the duct work and to other system components. Some service providers
may also suggest applying chemical treatments (sealants or other
encapsulants) to seal or cover the inside surfaces of the air ducts and
equipment housings because they believe the sealant will control mold
growth or prevent the release of dirt particles or fibers from ducts. These
practices have yet to be fully researched and you should be fully
informed before deciding to permit the use of biocides or sealants in
your air ducts. They should only be applied, if at all, after the
system has been properly cleaned of all visible dust or debris. [Click
on the thumbnail for a full page "printable" version of the
graphic below.]
Components of a Typical*
Residential Heating and
Cooling System
Upright Indoor System
w/gas furnace
*Type (e.g., heat pump, gas, electric), size, position
and location of system components will vary.
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Knowledge about the potential benefits and possible problems
of air duct cleaning is limited. Since conditions in every home are
different, it is impossible to generalize about whether or not air duct
cleaning in your home would be beneficial.
If no one in your household suffers from allergies or unexplained
symptoms or illnesses and if, after a visual inspection of the inside of
the ducts, you see no indication that your air ducts are contaminated
with large deposits of dust or mold (no musty odor or visible mold
growth), having your air ducts cleaned is probably unnecessary. It is
normal for the return registers to get dusty as dust-laden air is pulled
through the grate. This does not indicate that your air ducts are
contaminated with heavy deposits of dust or debris; the registers can be
easily vacuumed or removed and cleaned.
On the other hand, if family members are experiencing unusual or
unexplained symptoms or illnesses that you think might be related to
your home environment, you should discuss the situation with your
doctor. EPA has published Indoor
Air Quality: An Introduction for Health Professionals that can
be obtained free of charge by contacting IAQ INFO at the number listed
in this guide. You may obtain another free EPA booklet from IAQ INFO
entitled The
Inside Story: A Guide to Indoor Air Quality for guidance on
identifying possible indoor air quality problems and ways to prevent or
fix them.
You may consider having your air ducts cleaned simply because it
seems logical that air ducts will get dirty over time and should
occasionally be cleaned. While the debate about the value of periodic
duct cleaning continues, no evidence suggests that such cleaning would
be detrimental, provided that it is done properly.
On the other hand, if a service provider fails to follow proper duct
cleaning procedures, duct cleaning can cause indoor air problems. For
example, an inadequate vacuum collection system can release more dust,
dirt, and other contaminants than if you had left the ducts alone. A
careless or inadequately trained service provider can damage your ducts
or heating and cooling system, possibly increasing your heating and air
conditioning costs or forcing you to undertake difficult and costly
repairs or replacements.
You should consider having the air ducts in your home cleaned
if:
There is substantial visible mold growth inside hard surface (e.g.,
sheet metal) ducts or on other components of your heating and cooling
system. There are several important points to understand concerning
mold detection in heating and cooling systems:
 | Many sections of your heating and cooling system may not be
accessible for a visible inspection, so ask the service provider
to show you any mold they say exists.
| You should be aware that although a substance may look like
mold, a positive determination of whether it is mold or not can be
made only by an expert and may require laboratory analysis for
final confirmation. For about $50, some microbiology laboratories
can tell you whether a sample sent to them on a clear strip of
sticky household tape is mold or simply a substance that resembles
it.
| If you have insulated air ducts and the insulation gets wet or
moldy it cannot be effectively cleaned and should be removed and
replaced.
| If the conditions causing the mold growth in the first place are
not corrected, mold growth will recur. |
| | |
Ducts are infested with vermin, e.g. (rodents or insects); or
Ducts are clogged with excessive amounts of dust and debris and/or
particles are actually released into the home from your supply
registers.
Other Important Considerations...
Duct cleaning has never been shown to actually prevent health
problems. Neither do studies conclusively demonstrate that particle
(e.g., dust) levels in homes increase because of dirty air ducts or go
down after cleaning. This is because much of the dirt that may
accumulate inside air ducts adheres to duct surfaces and does not
necessarily enter the living space. It is important to keep in mind that
dirty air ducts are only one of many possible sources of particles that
are present in homes. Pollutants that enter the home both from outdoors
and indoor activities such as cooking, cleaning, smoking, or just moving
around can cause greater exposure to contaminants than dirty air ducts.
Moreover, there is no evidence that a light amount of household dust or
other particulate matter in air ducts poses any risk to health.
EPA does not recommend that air ducts be cleaned except on an
as-needed basis because of the continuing uncertainty about the benefits
of duct cleaning under most circumstances. If a service provider or
advertiser asserts that EPA recommends routine duct cleaning or makes
claims about its health benefits, you should notify EPA by writing to
the address listed at the end of this guidance. EPA does, however,
recommend that if you have a fuel burning furnace, stove, or fireplace,
they be inspected for proper functioning and serviced before each
heating season to protect against carbon monoxide poisoning. Some
research also suggests that cleaning dirty cooling coils, fans and heat
exchangers can improve the efficiency of heating and cooling systems.
However, little evidence exists to indicate that simply cleaning the
duct system will increase your system's efficiency.
If you think duct cleaning might be a good idea for your home, but
you are not sure, talk to a professional. The company that services your
heating and cooling system may be a good source of advice. You may also
want to contact professional duct cleaning service providers and ask
them about the services they provide. Remember, they are trying to sell
you a service, so ask questions and insist on complete and knowledgeable
answers.
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To find companies that provide duct cleaning services, check
your Yellow Pages under "duct cleaning" or contact the National
Air Duct Cleaners Association (NADCA) at the address and phone
number in the information section located at the end of this guidance.
Do not assume that all duct cleaning service providers are equally
knowledgeable and responsible. Talk to at least three different service
providers and get written estimates before deciding whether to have your
ducts cleaned. When the service providers come to your home, ask them to
show you the contamination that would justify having your ducts cleaned.
Do not hire duct cleaners who make sweeping claims about the health
benefits of duct cleaning -- such claims are unsubstantiated. Do not
hire duct cleaners who recommend duct cleaning as a routine
part of your heating and cooling system maintenance. You should also
be wary of duct cleaners who claim to be certified by EPA. EPA neither
establishes duct cleaning standards nor certifies, endorses, or
approves duct cleaning companies.
Do not allow the use of chemical biocides or sealants unless you
fully understand the pros and the cons (See
"Unresolved Issues of Duct Cleaning).
Check references to be sure other customers were satisfied and did
not experience any problems with their heating and cooling system
after cleaning.
Contact your county or city office of consumer affairs or local
Better Business Bureau to determine if complaints have been lodged
against any of the companies you are considering.
Interview potential service providers to ensure:
| they are experienced in duct cleaning and have worked on systems
like yours;
| they will use procedures to protect you, your pets, and your
home from contamination; and
| they comply with NADCA's air duct cleaning
standards and, if your ducts are constructed of fiber glass duct
board or insulated internally with fiber glass duct liner, with
the North American Insulation Manufacturers
Association's (NAIMA) recommendations.
|
| |
Ask the service provider whether they hold any relevant state
licenses. As of 1996, the following states require air duct cleaners
to hold special licenses: Arizona, Arkansas, California, Florida,
Georgia, Michigan and Texas. Other states may require them as well.
If the service provider charges by the hour, request an estimate of
the number of hours or days the job will take, and find out whether
there will be interruptions in the work. Make sure the duct cleaner
you choose will provide a written agreement outlining the total cost
and scope of the job before work begins.
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What
to Expect From an Air Duct Cleaning Service Provider
If you choose to have your ducts cleaned, the service provider
should:
| Open access ports or doors to allow the entire system to be
cleaned and inspected.
| Inspect the system before cleaning to be sure that there are no
asbestos-containing materials (e.g., insulation, register boots,
etc.) in the heating and cooling system. Asbestos-containing
materials require specialized procedures and should not be disturbed
or removed except by specially trained and equipped contractors.
| Use vacuum equipment that exhausts particles outside of the home
or use only high-efficiency particle air (HEPA) vacuuming equipment
if the vacuum exhausts inside the home.
| Protect carpet and household furnishings during cleaning.
| Use well-controlled brushing of duct surfaces in conjunction with
contact vacuum cleaning to dislodge dust and other particles.
| Use only soft-bristled brushes for fiberglass duct board and sheet
metal ducts internally lined with fiberglass. (Although flex duct
can also be cleaned using soft-bristled brushes, it can be more
economical to simply replace accessible flex duct.)
| Take care to protect the duct work, including sealing and
re-insulating any access holes the service provider may have made or
used so they are airtight.
| Follow NADCA's standards for air duct
cleaning and NAIMA's recommended practice for
ducts containing fiber glass lining or constructed of fiber glass
duct board. |
| | | | | | |
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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.
If you answer "No" to any of the questions on the
checklist, this may indicate a problem with the job. Ask your service
provider to correct any deficiencies until you can answer
"yes" to all the questions on the checklist.
Post-Cleaning Consumer Checklist
|
Yes |
No |
| General |
Did the service provider obtain access to and clean the
entire heating and cooling system, including ductwork and all
components (drain pans, humidifiers, coils, and fans)? |
|
|
| Has the service provider adequately demonstrated that duct
work and plenums are clean? (Plenum is a space in which supply
or return air is mixed or moves; can be duct, joist space,
attic and crawl spaces, or wall cavity.) |
|
|
| Heating |
Is the heat exchanger surface visibly clean? |
|
|
Cooling
Components |
Are both sides of the cooling coil visibly clean? |
|
|
| If you point a flashlight into the cooling coil, does light
shine through the other side? It should if the coil is clean. |
|
|
| Are the coil fins straight and evenly spaced (as opposed to
being bent over and smashed together)? |
|
|
| Is the coil drain pan completely clean and draining
properly? |
|
|
| Blower |
Are the blower blades clean and free of oil and debris? |
|
|
| Is the blower compartment free of visible dust or debris? |
|
|
Plenums
|
Is the return air plenum free of visible dust
or debris? |
|
|
| Do filters fit properly and are they the proper
efficiency as recommended by HVAC system manufacturer? |
|
|
| Is the supply air plenum (directly downstream of the air
handling unit) free of moisture stains and contaminants? |
|
|
| Metal Ducts |
Are interior ductwork surfaces free of visible debris?
(Select several sites at random in both the return and supply
sides of the system.) |
|
|
| Fiber Glass |
Is all fiber glass material in good condition (i.e., free of
tears and abrasions; well adhered to underlying materials)? |
|
|
Access
Doors |
Are newly installed access doors in sheet metal ducts
attached with more than just duct tape (e.g., screws, rivets,
mastic, etc.)? |
|
|
With the system running, is air leakage through access doors
or
covers very slight or non-existent? |
|
|
| Air Vents |
Have all registers, grilles, and diffusers been firmly
reattached to the walls, floors, and/or ceilings? |
|
|
| Are the registers, grilles, and diffusers visibly clean? |
|
|
System
Operation |
Does the system function properly in both the heating and
cooling modes after cleaning? |
|
|
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Whether or not you decide to have the air ducts in your home
cleaned, committing to a good preventive maintenance program is
essential to minimize duct contamination.
To prevent dirt from entering the system:
| Use the highest efficiency air filter recommended by the
manufacturer of your heating and cooling system.
| Change filters regularly.
| If your filters become clogged, change them more frequently.
| Be sure you do not have any missing filters and that air cannot
bypass filters through gaps around the filter holder.
| When having your heating and cooling system maintained or checked
for other reasons, be sure to ask the service provider to clean
cooling coils and drain pans.
| During construction or renovation work that produces dust in your
home, seal off supply and return registers and do not operate the
heating and cooling system until after cleaning up the dust.
| Remove dust and vacuum your home regularly. (Use a high efficiency
vacuum (HEPA) cleaner or the highest efficiency filter bags your
vacuum cleaner can take. Vacuuming can increase the amount of dust
in the air during and after vacuuming as well as in your ducts).
| If your heating system includes in-duct humidification equipment,
be sure to operate and maintain the humidifier strictly as
recommended by the manufacturer. |
| | | | | | |
To prevent ducts from becoming wet:
Moisture should not be present in ducts. Controlling moisture is the
most effective way to prevent biological growth in air ducts.
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:
| Promptly and properly repair any leaks or water damage.
| 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.
| Make sure ducts are properly sealed and insulated in all
non-air-conditioned spaces (e.g., attics and crawl spaces). This
will help to prevent moisture due to condensation from entering the
system and is important to make the system work as intended. To
prevent water condensation, the heating and cooling system must be
properly insulated. |
| |
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Does duct cleaning prevent health problems?
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.
In the meantime...
Educate yourself about duct cleaning by contacting some or all
of the sources of information listed at the end of this publication
and asking questions of potential service providers.
Are duct materials other than bare sheet metal ducts
more likely to be contaminated with mold and other biological
contaminants?
You may be familiar with air ducts that are constructed of
sheet metal. However, many modern residential air duct systems are
constructed of fiber glass duct board or sheet metal ducts that are
lined on the inside with fiber glass duct liner. Since the early 1970's,
a significant increase in the use of flexible duct, which generally is
internally lined with plastic or some other type of material, has
occurred. The use of insulated duct material has increased due to
improved temperature control, energy conservation, and reduced
condensation. Internal insulation provides better acoustical (noise)
control. Flexible duct is very low cost. These products are engineered
specifically for use in ducts or as ducts themselves, and are tested in
accordance with standards established by Underwriters Laboratories (UL),
the American Society for Testing and Materials (ASTM), and the National
Fire Protection Association (NFPA).
Many insulated duct systems have operated for years without
supporting significant mold growth. Keeping them reasonably clean and
dry is generally adequate. However, there is substantial debate about
whether porous insulation materials (e.g., fiber glass) are more prone
to microbial contamination than bare sheet metal ducts. If enough dirt
and moisture are permitted to enter the duct system, there may be no
significant difference in the rate or extent of microbial growth in
internally lined or bare sheet metal ducts. However, treatment of mold
contamination on bare sheet metal is much easier. Cleaning and treatment
with an EPA-registered biocide are possible. Once fiberglass duct liner
is contaminated with mold, cleaning is not sufficient to prevent
re-growth and there are no EPA-registered biocides for the treatment of
porous duct materials. EPA, NADCA, and NAIMA
all recommend the replacement of wet or moldy fiber glass duct material.
In the meantime...
Experts do agree that moisture should not be present in ducts and
if moisture and dirt are present, the potential exists for biological
contaminants to grow and be distributed throughout the home.
Controlling moisture is the most effective way to prevent biological
growth in all types of air ducts.
Correct any water leaks or standing water.
Remove standing water under cooling coils of air handling units by
making sure that drain pans slope toward the drain.
If humidifiers are used, they must be properly maintained.
Air handling units should be constructed so that maintenance
personnel have easy, direct access to heat exchange components and
drain pans for proper cleaning and maintenance.
Fiber glass, or any other insulation material that is wet or
visibly moldy (or if an unacceptable odor is present) should be
removed and replaced by a qualified heating and cooling system
contractor.
Steam cleaning and other methods involving moisture should not be
used on any kind of duct work.
Should chemical biocides be applied to the inside of air ducts?
Air duct cleaning service providers may tell you that they
need to apply a chemical biocide to the inside of your ducts to kill
bacteria (germs), and fungi (mold) and prevent future biological growth.
Some duct cleaning service providers may propose to introduce ozone to
kill biological contaminants. Ozone is a highly reactive gas that is
regulated in the outside air as a lung irritant. However, there remains
considerable controversy over the necessity and wisdom of introducing
chemical biocides or ozone into the duct work.
Among the possible problems with biocide and ozone application in air
ducts:
| Little research has been conducted to demonstrate the
effectiveness of most biocides and ozone when used inside ducts.
Simply spraying or otherwise introducing these materials into the
operating duct system may cause much of the material to be
transported through the system and released into other areas of your
home.
| Some people may react negatively to the biocide or ozone, causing
adverse health reactions. |
|
Chemical biocides are regulated by EPA under Federal pesticide law. A
product must be registered by EPA for a specific use before it can be
legally used for that purpose. The specific use(s) must appear on the
pesticide (e.g., biocide) label, along with other important information.
It is a violation of federal law to use a pesticide product in any
manner inconsistent with the label directions.
A small number of products are currently registered by EPA
specifically for use on the inside of bare sheet metal air ducts. A
number of products are also registered for use as sanitizers on hard
surfaces, which could include the interior of bare sheet metal ducts.
While many such products may be used legally inside of unlined ducts if
all label directions are followed, some of the directions on the label
may be inappropriate for use in ducts. For example, if the directions
indicate "rinse with water", the added moisture could
stimulate mold growth.
All of the products discussed above are registered solely for the
purpose of sanitizing the smooth surfaces of unlined (bare) sheet metal
ducts. No products are currently registered as biocides for use on fiber
glass duct board or fiber glass lined ducts, so it is important to
determine if sections of your system contain these materials before
permitting the application of any biocide.
In the meantime...
Before allowing a service provider to use a chemical biocide in your
duct work, the service provider should:
| Demonstrate visible evidence of microbial growth in your duct
work. Some service providers may attempt to convince you that
your air ducts are contaminated by demonstrating that the
microorganisms found in your home grow on a settling plate (i.e.,
petri dish). This is inappropriate. Some microorganisms are always
present in the air, and some growth on a settling plate is normal.
As noted earlier, only an expert can positively identify a
substance as biological growth and lab analysis may be required
for final confirmation. Other testing methods are not reliable.
| Explain why biological growth cannot be removed by physical
means, such as brushing, and further growth prevented by
controlling moisture. |
|
If you decide to permit the use of a biocide, the service provider
should:
| Show you the biocide label, which will describe its range of
approved uses.
| Apply the biocide only to un-insulated areas of the duct
system after proper cleaning, if necessary to reduce the chances
for re-growth of mold.
| Always use the product strictly according to its label
instructions. |
| |
While some low toxicity products may be legally applied while
occupants of the home are present, you may wish to consider leaving the
premises while the biocide is being applied as an added precaution.
Do sealants prevent the release of dust and dirt particles into
the air?
Manufacturers of products marketed to coat and seal duct
surfaces claim that these sealants prevent dust and dirt particles
inside air ducts from being released into the air. As with biocides, a
sealant is often applied by spraying it into the operating duct system.
Laboratory tests indicate that materials introduced in this manner tend
not to completely coat the duct surface. Application of sealants may
also affect the acoustical (noise) and fire retarding characteristics of
fiber glass lined or constructed ducts and may invalidate the
manufacturer's warranty.
Questions about the safety, effectiveness and overall desirability of
sealants remain. For example, little is known about the potential
toxicity of these products under typical use conditions or in the event
they catch fire.
In addition, sealants have yet to be evaluated for their resistance
to deterioration over time which could add particles to the duct air.
In the meantime...
Most organizations concerned with duct cleaning, including EPA, NADCA,
NAIMA, and the Sheet Metal and Air Conditioning
Contractors' National Association (SMACNA) do not currently recommend
the routine use of sealants in any type of duct. Instances when the use
of sealants may be appropriate include the repair of damaged fiber glass
insulation or when combating fire damage within ducts. Sealants should
never be used on wet duct liner, to cover actively growing mold, or to
cover debris in the ducts, and should only be applied after cleaning
according to NADCA or other appropriate guidelines
or standards.
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U.S. Environmental Protection Agency
Office of Radiation and Indoor Air
Indoor Environments Division (6609J)
Arial Rios Building
1200 Pennsylvania Avenue, N.W.
Washington, DC 20460
(202) 564-9370
(202) 565-2038/39 (fax)
Indoor Air Quality Information
Clearinghouse (IAQ INFO)
P.O. Box 37133
Washington, DC 20013-7133
1 (800) 438-4318
(703) 356-4020 (local)
(703) 356-5386 (fax)
E-mail: IAQINFO@aol.com
The following useful EPA publications are
available on this web site and for free of charge (including copies of
this document, from IAQINFO and from NCEP. (see also: http://www.epa.gov/iaq/pubs/)
Consumer Research Council (CRC)
IAQ Checklist
P.O. Box 12099
Washington, DC 20005-0999
Ask for: How Healthy Is The Air In Your Home? (This is a
free resource, you will need to send a self-addressed, stamped
standard size business envelope)
To Learn More About Air Duct Cleaning
National Air Duct Cleaners
Association (NADCA)
1518 K Street, NW Suite 503
Washington, DC 20005
(202) 737-2926
http://www.nadca.com
Ask for: Introduction to HVAC (Heating, Ventilating, and Air
Conditioning) System Cleaning Services
(Although intended for commercial customers, information can be useful
to consumers.)
North American Insulation
Manufacturers Association (NAIMA)
44 Canal Center Plaza, Suite 310
Alexandria, VA 22314
(703) 684-0084
www.naima.org/
Ask for: Cleaning Fibrous Glass Insulated Air Duct Systems;
Recommended Practice
Other Useful Resources
For a free list of state and local consumer
protection agencies and Better Business Bureaus:
Consumer's Resource Handbook
Consumer Information Center
Pueblo, CO 81009
For more information on biocides:
EPA's Antimicrobial Hotline
Antimicrobial Division
Office of Pesticide Programs
Phone: (703) 308-0127, or (703) 305-1284, or (703) 308-6432
Fax: (703) 308-6467
E-mail: Info_Antimicrobial@epa.gov
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| Consumer
Checklist |
 |
Learn as much as possible about air duct
cleaning before you decide to have your ducts cleaned by
reading this guidance and contacting the sources of
information provided.
|
|
Consider other possible
sources of indoor air pollution first if you suspect an indoor
air quality problem exists in your home.
|
|
Have your air ducts cleaned if they are
visibly contaminated with substantial mold growth, pests or
vermin, or are clogged with substantial deposits of dust or
debris.
|
|
Ask the service provider to show you any
mold or other biological contamination they say exists. Get
laboratory confirmation of mold growth or decide to rely on
your own judgment and common sense in evaluating apparent mold
growth.
|
|
Get estimates from at least three
service providers.
|
|
Check references.
|
|
Ask the service provider whether he/she
holds any relevant state licenses. As of 1996, the following
states require air duct cleaners to hold special licenses:
Arizona, Arkansas, California, Florida, Georgia, Michigan and
Texas. Other states may also require licenses.
|
|
Insist that the service provider give
you knowledgeable and complete answers to your questions.
|
|
Find out whether your ducts are made of
sheet metal, flex duct, or constructed of fiber glass duct
board or lined with fiber glass since the methods of cleaning
vary depending on duct type. Remember, a combination of these
elements may be present.
|
|
Permit the application of biocides in
your ducts only if necessary to control mold growth and only
after assuring yourself that the product will be applied
strictly according to label directions. As a precaution, you
and your pets should leave the premises during application.
|
|
Do not permit the use of sealants except
under unusual circumstances where other alternatives are not
feasible.
|
|
Make sure the service provider follows
the National Air Duct Cleaning Association's
(NADCA) standards and, if the ducts are constructed of
flex duct, duct board, or lined with fiber glass, the
guidelines of the North American Insulation
Manufacturers Association (NAIMA).
|
|
Commit to a preventive maintenance
program of yearly inspections of your heating and cooling
system, regular filter changes, and steps to prevent moisture
contamination.
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