Duct Cleaning - Is It Necessary

What is Air Duct Cleaning?
Duct cleaning - to clean or not to clean? This is the question many new homeowners ask. This is especially true for people moving into homes where previous owners had pets and allergies are involved. This is not the only reason to have your ducts cleaned.
If ducts and related equipment are 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. 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 industry associations concerned have established standards with air duct cleaning. Typically, a service provider will use specialized tools to dislodge dirt and other debris in ducts, and then vacuum them out with a high-powered vacuum cleaner.

Some companies may apply chemical biocides, designed to kill microbiological contaminants, to the inside of the ductwork and to other system components. Some duct cleaning companies may also suggest applying chemical treatments to encapsulate or cover the inside surfaces of the air ducts and equipment housings because they believe it 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 chemical treatments 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.


Deciding Whether or Not to Have Your Air Ducts Cleaned


Duct cleaning is probably not necessary if no one in your home suffers from allergies or r illnesses and if, after a visual inspection of the inside of the ducts, you see no signs that your air ducts are harboring large deposits of dust or mold, having your air ducts cleaned is probably not required. Return registers normally 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. Attaching a register filter will probably supply all the cleaning power you need.

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 family doctor.
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. There is no evidence that duct cleaning will make the air in your home safer of more comfortable but having you ducts cleaned will not harm anyone.
Using a unprofessional duct cleaning service who fails to follow proper duct cleaning procedures, can cause indoor air problems. Damage to your system or loosening up of contaminates followed by improper vacuuming can lead to harmful products being distributed throughout your home.

Signs that could indicate your ducts require cleaning include is visible mold growth inside 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, they are:
1. Many sections of your heating and cooling system may not be accessible for a visible inspection. Ask your duct cleaner to show you any mold they find.
2. Types of mold can not be determined by sight. These samples must be sent to a laboratory for analysis.
3. Mould in duct insulation can only be fixed by replacing insulation.
4. Mold will continually grow until originating condition is resolved.
5. Ducts are infested with vermin, e.g. (rodents or insects); or
6. Ducts are clogged with excessive amounts of dust and debris and/or particles are actually released into the home from your supply registers. This can be found in new construction where contractors swept debris into register holes during construction.
Health Considerations ... There has never been any prove that duct cleaning can improve health conditions. Many items in a house may contribute to allergies and lung disorders such as, cooking, open windows and doors, and furniture and fibres used in the home.

When choosing a duct cleaning service, phone around and ask about what services they provide. Check with your furnace or a/c servicing company and ask who they recommend. Ask them to come to your house and give an estimate and whether your ducts even require cleaning.

Do not allow the use of chemical biocides or chemical treatments to be used on your ducts and heating equipment unless you fully understand the pros and the cons.

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.

Items to Check that your Duct Cleaning Company does:
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 in the heating and cooling system. 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.

Post-Cleaning Consumer Checklist
GeneralDid 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.)
HeatingIs 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? Is the coil drain pan completely clean and draining properly?
BlowerAre the blower blades clean and free of oil and debris?Is the blower compartment free of visible dust or debris?
PlenumsIs 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 free of moisture stains and contaminants?

Metal Ducts: Are interior ductwork surfaces free of visible debris?
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?

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 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:
1. Promptly and properly repair any leaks or water damage.
2. 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.
3. The presence of substantial standing water and/or debris indicates a problem requiring immediate attention. Check any insulation near cooling coils for wet spots.
4. Make sure ducts are properly sealed and insulated in all non-air-conditioned spaces. This will help to prevent moisture due to condensation from entering the system and is important to make the system work as intended.

If you decide to get your ducts cleaned, make your decision based on the facts, not the sales hype from some salesman who may use health risks and other unproven data to secure a contract.