Posted on 04/20/2020

Dear NADCA Members,

Please see below for answers to some of the frequently asked questions we've received in response to COVID-19.

1. Is air duct/HVAC system cleaning effective in mitigating COVID-19?

We continue to learn more each day regarding how COVID-19 is spread and there is no definitive research to conclude exactly what role the HVAC system may or may not play in its spread. At this time, no one can definitively say whether or not air duct/HVAC system cleaning is effective in mitigating the spread of COVID-19.

2. Is it acceptable to make statements or marketing claims that air duct/HVAC system cleaning services sanitize and/or disinfect?

Due to the spread of COVID-19, NADCA anticipates a greater consumer demand for NADCA members to "sanitize" or "disinfect" HVAC systems.  Numerous antimicrobials on the market have been approved for use in HVAC systems and in HVAC ductwork.  These could be helpful to NADCA members in treating HVAC systems if these products are used in accordance with the law and the instructions on the label and if these products are specifically stated by the manufacturer to be effective against COVID-19.

However, as noted in NADCA's White Paper, "Chemical Product Applications in HVAC Systems," the terms "sanitize" and "disinfect" are legal terms in the U.S. and other countries with specific meanings (they define very high kill rates).  Not all antimicrobials approved for HVAC components can be claimed to "sanitize" or "disinfect."  We encourage NADCA members to use correct language - as described on product labels - in their proposals, marketing, and client communications in discussing the option of applying antimicrobials to HVAC systems or components.

The full White Paper is available for free download here:

Download the White Paper

It is also important to note that cleaned and treated surfaces can become re-contaminated in minutes if a COVID-19 infected individual is present and sneezes or coughs without controlling the droplet spread. It is important that contractors performing cleaning services not make statements claiming disinfection, sanitization or prevention of spread of COVID-19, but rather that the cleaning has been performed and a particular product was applied in accordance with EPA-registered product label.

3. Where can I find information about what products may be used against COVID-19?

The EPA's List N: Products with Emerging Viral Pathogens AND Human Coronavirus provides a list of products that meet EPA’s criteria for use against SARS-CoV-2, the virus that causes COVID-19. It is critical that these products are applied in the manner prescribed on their EPA registered label. 


Additional Considerations

Scope of Practice

Contractors should only offer services related to mitigation of COVID-19 if they are equipped with the proper training, equipment, and insurance to perform these services and have experience in dealing properly with other biological contaminants. Third-party Industrial Hygienists should be consulted for the development of cleaning protocols related specifically to the mitigation of COVID-19.

Protection of Workers

For essential work activities that require your employees to be deployed in the field, be sure to put in place specific controls and training to minimize risk. It is critical that employees utilize and are trained on the use of proper Personal Protective Equipment (PPE). It is important to determine whether workers may be exposed to sources of infectious diseases. Companies should refer to OSHA resources for additional information pertaining to site-specific hazard assessment to protect the health and safety of workers.

Cross Contamination

Engineering controls must be used to ensure worker safety and health, and to prevent cross-contamination. Before any equipment is brought onto the work site it must be cleaned and inspected to ensure that it will not introduce contaminants into the indoor environment or HVAC system. All collection devices, vacuums and other tools and devices must be cleaned or sealed before relocating to different areas of a building and before removing the equipment from the building.

Additional References & Resources

CDC COVID-19 Resources

OSHA COVID-19 Resources

EPA COVID-19 Resources

WHO COVID-19 Resources

ACR, The NADCA Standard

NADCA White Paper, Using Chemical Products in HVAC Systems

NADCA COVID-19 Resources

“Guidance for Building Operations During the COVID-19 Pandemic”, ASHRAE Journal Newsletter



Anyone using this document should understand the document’s limitations, and rely on his or her judgment, or as appropriate, seek the advice of a competent professional in determining the exercise of reasonable care in any situation. NADCA makes no representation or warranty as to, and is not responsible for, the contents, validity or application of the information by any recipient of this document. NADCA does not warrant that the information in this document is free of errors and the entire risk of the use of any information in this document is assumed by the user.