411HomeServices.com 411 Home Services

Library of Helpful Tips for Home Owners

Duct Cleaning Services

Line up Your Ducts Before You Call the Duct Cleaner!
Things to Consider and Tips about Air Duct Cleaning

If you think duct cleaning might be a good idea for your home, but you are not sure, talk to the company that services your heating and cooling system, and contact a professional duct cleaning service provider. Ask them about the services they provide and insist on complete and knowledgeable answers. Free estimates are common.

What is Air Duct Cleaning?

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.

Find out whether your ducts are made of sheet metal, flex duct, or constructed of fiberglass duct board or lined with fiberglass since the methods of cleaning vary depending on duct type. Remember, a combination of these elements may be present.

Methods of duct cleaning vary. 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. See note at the end about the use of biocides and sealants.

Although it is not necessary to clean air ducts on a regular basis, it is 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. Commit to a preventive maintenance program of yearly inspections of your heating and cooling system, regular filter changes, and steps to prevent moisture contamination. Ask the service provider to clean cooling coils and drain pans.

You should consider having the air ducts in your home cleaned if :

  • There is substantial visible mold growth inside sheet metal ducts or on other components of your heating and cooling system. 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, or get it tested at a lab. Although a substance may look like mold, it may not be.
  • If you have insulated or flex air ducts and the insulation gets wet or moldy it cannot be effectively cleaned and should be removed and replaced.
  • If ducts are infested with vermin, e.g. (rodents or insects)
  • If ducts are clogged with excessive amounts of dust and debris and/or particles are actually released into the home from your supply registers.

Prior to any cleaning, retrofitting, or replacing of your ducts, the cause or causes of any serious problems must be corrected or they will likely recur.

When You Do Decide to Have Your Air Ducts Cleaned:

Ask service provider to show you the contamination that would justify having your ducts cleaned.
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.
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 national cleaning association standards and hold relevant licenses (these vary with location).
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.
If the charged by the hour, request an estimate of the number of hours the job will take, and find out whether there will be interruptions in the work. Get a written agreement outlining the total cost and scope of the job before work begins.
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 the U.S.Environmental Protection Agency. The EPA neither establishes duct-cleaning standards nor certifies, endorses, or approves duct-cleaning companies.

Important Note: If a service provider fails to follow proper duct cleaning procedures, it 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.

What to Expect From an Air Duct Cleaning Service Provider

The service provider should:

  1. Open access ports or doors to allow the entire system to be cleaned and inspected.
  2. Inspect the system before cleaning to be sure that there are no asbestos-containing materials 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.
  3. 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.
  4. Protect carpet and household furnishings during cleaning.
  5. Use well-controlled brushing of duct surfaces in conjunction with contact vacuum cleaning to dislodge dust and other particles.
  6. 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.)
  7. 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.

How to Determine if the Duct Cleaner Did A Thorough Job

All portions of the system should be visibly clean. After completing the job, ask the service provider to show you each component of your system to verify that the job was performed satisfactorily:

  • Did the service provider clean the entire heating and cooling system, including duct work 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.)
  • 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?


  • Are the blower blades clean and free of oil and debris? Is the blower compartment free of visible dust or debris?

A Note About Chemical Biocides and Sealants

Do not allow the use of chemical biocides or chemical treatments unless you fully understand the pros and the cons.

Before allowing the use of a chemical biocide in your duct work, the service provider should explain why the biological growth cannot be removed by physical means, such as brushing, and further growth prevented by controlling moisture. 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.

While the targeted use of chemical biocides and sealants may be appropriate under specific circumstances, research has not demonstrated their effectiveness in duct cleaning or their potential adverse health effects.

They should only be applied, if at all, after the system has been properly cleaned of all visible dust or debris. It is especially not recommended for internally insulated air duct systems.

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.

Note: Use of sealants to encapsulate the inside surface of ducts is a different practice than sealing duct air leaks. Sealing duct air leaks can help save energy on heating and cooling bills.

A Final Word

Duct cleaning has never been shown to actually prevent health problems because much of the dirt in air ducts adheres to duct surfaces and does not necessarily enter the living space. However, knowledge about air duct cleaning is in its early stages.

It is normal for the return registers to get dusty. This does not indicate that your air ducts are contaminated with 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. Duct cleaning may be part of a comprehensive clean up.

This paper is intended for informational purposes only. Nothing contained herein constitutes legal, financial or other professional advice. Transmission of these materials is not intended to create, and receipt does not constitute, any relationship of any kind between the provider and the recipient. Some of these points may not apply in your area. Different term and conditions may vary from state to state and province to province. All articles, text and photographic material presented here is for the use and pleasure of the recipient only. Download PDF

Need more HELP! Information you need to know about your DUCTS,

Find Duct Cleaning Services Near You

Click to open larger map
Ashburn, United States
Discover where the real wealth is in property!
Duct Cleaning Services
Near Ashburn, United States

Comments are closed.