Frequently Asked Questions

Frequently Asked Questions

Frequently Asked Questions About Air Duct Cleaning



What is an “Air Systems Cleaning Specialist”


An Air System Cleaning Specialist (ASCS) is a certification earned through the National Air Duct Cleaning Association (NADCA).  It signifies a high level of professionalism in the HVAC air duct cleaning industry. An air duct systems cleaning specialist has demonstrated a high degree of knowledge relating to HVAC air duct system cleaning standards as established by the NADCA, based on OSHA regulations and other important standards relating to clean air duct quality.  An air duct cleaning specialist has passed a rigorous certification examination. 



Certified Ventilation System Inspector


Certified HVAC Ventilation Inspectors (CVI) undergo training based on the Environmental Protection Agency’s (EPA) I-BEAM program, which provides a structured method of doing inspections, in compliance with NADCA’s standards and guidelines. The training and certification examination covers applicable building and IAQ standards and codes, maintenance and housekeeping programs, diagnosing IAQ problems and reporting findings to building owners.



Ventilation System Mold Remediator


Ventilation System Mold Remediators  have undergone training thorough the National Air Duct Cleaning Association to ensures they have an understanding of basic microbiological contamination, project assessment, and they have learned how to apply NADCA and other industry standards to their work.  They have also passed a rigorous examination which tests their knowledge of microbiological agents and they have learned how to perform project assessments, as well as apply industry guidelines and standards to their work.  A Ventilation Systems Mold Remediator must have an ASCS and/or CMR certification from the National Air Duct Cleaning Association before obtaining VSMR certification.


Air Duct Cleaning – What Are Some Guidelines To Help Me Select An Air Duct Cleaning Residential Contractor?

 Ask these questions when talking with an air duct cleaning company you are considering:



1.                            How long has the contractor been in the residential  HVAC business doing air duct system cleaning business?

2.                            As the air duct cleaning contractor for proof of Worker’s Compensation and General Liability Insurance coverage? He should produce a Certificate of Insurance form.

3.                            Does the air duct cleaning contractor you are considering using require to be licensed?  You can find out if a license is required on your city, township or state websites.   These states requiring special licenses – Arizona, Arkansas, California, Florida, Georgia,  Michigan, Texas.

4.                            Ask the air duct cleaning contractor you are considering to provide 3 to 5 customer references with phone numbers for which they provided service in the last 30 days.

5.                            Ask the air duct cleaning HVAC contractor you are considering using if they will do a an inspection of your air duct cleaning system before they do any work and alert you to any potential problems.

6.                            Ask the air duct cleaning professional if they will provide a means to conduct a visual inspection at any time during the cleaning such as with mirrors, cameras or a remote visual systems.

7.                            Ask the air duct cleaning contractor if their service includes not just the air duct system but also the cleaning of coils and fans.

8.                            As the company doing the air duct cleaning contracting if they will perform the work or contract it out to another company.  If the work is to be contracted out, these questions should be asked of the contracted company. 

9.                            The air duct cleaning contractor should give you a price only after they have inspected your air duct system and HVAC system to avoid additional charges after the work starts.  



Are there any health benefits that come from HVAC system cleaning? 


Heating, ventilation, and air conditioning (HVAC) systems have been shown to act as a collection source for a variety of contaminants that have the potential to affect health, such as mold, fungi, bacteria, and very small particles of dust. The removal of such contaminants from the HVAC system and home should be considered as one component in an overall plan to improve indoor air quality. 




Will HVAC system cleaning reduce our home energy bills?


Research by the U.S. EPA has demonstrated that HVAC system cleaning may allow systems to run more efficiently by removing debris from sensitive mechanical components. Clean, efficient systems are less likely to break down, have a longer life span, and generally operate more effectively than dirty systems. 



How should a residential HVAC system be cleaned?


The most effective way to clean air ducts and ventilation systems is to employ Source Removal methods of cleaning. This requires a contractor to place the system under negative pressure, through the use of a specialized, powerful vacuum. While the vacuum draws air through the system, devices are inserted into the ducts to dislodge any debris that might be stuck to interior surfaces. The debris can then travel down the ducts to the vacuum, which removes it from the system and the home. 




What kind of equipment is best for cleaning-truck mounted vacuums or portable vacuums?


NADCA does not endorse one kind of equipment over another. There are two main types of vacuum collection devices: (1) those mounted on trucks and trailers, and (2) portable units. Truck/trailer mounted equipment is generally more powerful than portable equipment. However, portable equipment can often be brought directly into a facility, allowing the vacuum source to be located closer to the ductwork. Both types of equipment will clean to NADCA standards.

All vacuum units should be attached to a collection device for safe containment prior to disposal. Any vacuum collection device which exhausts indoors must be HEPA (high efficiency particulate arrestance) filtered.

A vacuum collection device alone will not get an HVAC system clean. The use of methods and tools designed to agitate debris adhered to the surfaces within the system, in conjunction with the use of the vacuum collection device(s), is required to clean HVAC systems. (For example: brushes, air whips, and “skipper balls.”)





How often should residential HVAC systems be cleaned? 


Frequency of cleaning depends on several factors, not the least of which is the preference of the home owner. Some of the things that may lead a home owner to consider more frequent cleaning include:

• Smokers in the household. 

• Pets that shed high amounts of hair and dander. 

• Water contamination or damage to the home or HVAC system.

• Residents with allergies or asthma who might benefit from a reduction in the amount of indoor air pollutants in the home’s HVAC system.

• After home renovations or remodeling. 

• Prior to occupancy of a new home.




What is the normal price range for the air duct cleaning service? 


The Environmental Protection Agency says that “duct cleaning services typically – but not always – range in cost from $450 to $1000 per heating and cooling system, depending on the services offered, the size of the system to be cleaned, system accessibility, climactic region, and level of contamination” and type of duct material.

Consumers should beware of air duct cleaning companies that making sweeping claims about the health benefits of duct cleaning – such claims are unsubstantiated. Consumers should also beware of “blow-and-go” air duct cleaning companies. These companies often charge a nominal fee and do a poor job of cleaning the heating and cooling system. These companies may also persuade the consumer into unneeded services with and/or without their permission.


(If you have knowledge of a practicing “blow-and-go” air duct cleaner, contact your local Better Business Bureau to report the company, and your local, federal, and state elected officials to demand legislation.)




What criteria should I use in selecting an HVAC system cleaner? 


Interview as many local contractors as you can. Ask them to come to your home and perform a system inspection and give you a quotation. To narrow down your pool of potential contractors, use the following pre-qualifications:


• Make sure the company is a member in good standing of the National Air Duct Cleaners Association (NADCA). 

• See if the company has been in business long enough to have adequate experience. 

• Inquire whether the company is in good standing with your local Better Business Bureau. 

• Get proof that the company is properly licensed and adequately insured. 

• Verify that the company is certified by NADCA to perform HVAC system cleaning. 

• Make sure that the company is going to clean and visually inspect all of the air ducts and related system components. 

• Avoid advertisements for “$99 whole house specials” and other sales gimmicks. 

• Ask if the company has the right equipment to effectively perform cleaning, and if the company has done work in homes similar to yours. Get references from neighbors if possible.




Why should I choose a NADCA member to have my air ducts cleaned? 


NADCA Members have signed a Code of Ethics stating they will do everything possible to protect the consumer, and follow NADCA Standards for cleaning to the best of their ability, for a list of NADCA members near you, click here. Air duct cleaning companies must meet stringent requirements to become a NADCA Member. Among those requirements, all NADCA Members must have certified Air System Cleaning Specialists (ASCS) on staff, who have taken and passed the NADCA Certification Examination. Passing the exam demonstrates extensive knowledge in HVAC design and cleaning methodologies. ASCS’s are also required to further their industry education by attending seminars in order to maintain their NADCA certification status.




What are sanitizers, and why would they need to be used? 


Sanitizers are anti-microbial chemicals applied to the interior surface of the air ducts, designed to control microbial contamination. Before any sanitizers are used, the system should be thoroughly cleaned. It is critical that any anti-microbial treatment used in your system be EPA registered for the intended use in HVAC systems. Ask to see the chemical’s Material Safety Data Sheet (MSDS). If you are still concerned, call the EPA at 1-800-438-4318.

It should be noted that there are no EPA registered anti-microbial products for use on porous system surfaces – such as fiberglass surfaces.




How long should it take to clean a typical residential HVAC system? 


The amount of time it takes to clean a residential HVAC system depends on many variables such as the size of the home, the number of systems, the extent of the contamination and the number of HVAC cleaners performing the job. Ask at least two contractors to inspect your system and give you a time estimate for your particular system. This will give you a general idea of how long the job should take as well as an idea of how thoroughly the contractor plans to do the job. 




How can we determine if the HVAC system cleaning was effective? 


The best way to determine if the HVAC system cleaning was effective is to perform a visual inspection of the system before and after cleaning. If any dust or debris can be seen during the visual inspection, the system should not be considered cleaned. While you can perform your own visual inspection using a flash light and mirror, a professional cleaning contractor should be able to allow you better access to system components and perhaps the use of specialized inspection tools. In addition, following this post-cleaning check list can help to ensure a top quality job.



Note:  Some of the questions and answers included above are based on research of the National Air Duct Cleaning Association web site.