What is Air Duct Cleaning?

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.

 

Components of a Typical*

Residential Heating and Cooling System

 

 

Deciding Whether or Not to Have Your Air Ducts Cleaned

 

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.

 

Suggestions for Choosing a Duct Cleaning Service Provider

 

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.

 

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.

 

How to Determine if the Duct Cleaner Did A Thorough Job

 

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.)

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Heating

 

Is the heat exchanger surface visibly clean?

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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?

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Blower

 

Are the blower blades clean and free of oil and debris?

 

Is the blower compartment free of visible dust or debris?

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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.)

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Fiber Glass

 

Is all fiber glass material in good condition (i.e.,

free of tears and abrasions; well adhered to underlying

materials)?

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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?

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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?

----------------------------------------------------------------------

 

How to Prevent Duct Contamination

 

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.

 

* If you are replacing your air conditioning system, make sure that the

unit is the proper size for your needs and that all ducts are sealed

at the joints. A unit that is too big will cycle on an off

frequently, resulting in poor moisture removal, particularly in areas

with high humidity. Also make sure that your new system is designed

to manage condensation effectively.

 

Unresolved Issues of Duct Cleaning

 

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

regrowth 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 regrowth 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.

 

To Learn More About Indoor Air Quality

 

U.S. Environmental Protection Agency

Office of Radiation and Indoor Air

Indoor Environments Division

(6604J) 401 M St., S.W.

Washington, DC 20460

(202) 564-9370

(202) 565-2038 (fax)

E-mail: webmaster.oria@epamail.epa.gov

World Wide Web Site: http://www.epa.gov/iaq/

 

Indoor Air Quality Information Clearinghouse (IAQ INFO)

P.O. Box 37133

Washington, DC 20013-7133

1 (800) 438-4318

(202) 484-1307

E-mail: IAQINFO@aol.com

 

Useful EPA publications available free of charge from either location

above:

 

The Inside Story: A Guide to Indoor Air Quality

Indoor Air Pollution: An Introduction for Health Professionals

Residential Air Cleaning Devices: A Summary of Available Information

 

Consumer Research Council (CRC) IAQ Checklist

P.O. Box 12099

Washington, DC 20005-0999

 

Ask for: How Healthy Is The Air In Your Home?

(Free. 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

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 Information on Antimicrobial Biocides:

 

National Antimicrobial Information Network (NAIN)

1 (800) 447-6349.

Email: nain@ace.orst.edu

 

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 judgement 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.