Maintaining Indoor Air Quality During the Covid-19 Pandemic

We have had non-stop questions about how your air conditioning system operation and maintenance needs to change during the Covid-19 pandemic. Here is the most up-to-date and accurate information that we have available to assist in making decisions for the health and safety of your home.

The Covid-19 virus emerged very quickly. It spread worldwide in a matter of a few months. There has not been a great deal of scientific data accumulated to conduct thorough studies to publish quantified results.  There has yet to be any evidence that the virus can be transmitted through an HVAC system. Most of the protocol and preventative measures are being based on similar viruses.

The Covid-19 information that we are sharing is based on that information.

Good News First! There has not been any confirmed proof that Covid-19 has been transmitted through the ductwork of an air conditioning system. As far as we know, this virus is primarily transmitted by direct contact with an infected person and by touching a contaminated surface.

Airborne Transmission

According to the experts, airborne transmission of Covid-19 is possible in theory. Respiratory droplets can keep virus particles airborne for hours. If this is possible, they could enter the air ventilation system. HOWEVER, scientists believe that Covid-19 transmission through this manner is negligible.

Mitigation Procedures

Covid-19 Mitigation tactics are helpful in reducing the possibility of your air conditioning system being contaminated with Covid-19. Reducing the potential exposure through mitigation must be part of a comprehensive plan to reduce person-to-person contact and contaminated surface contact.

FAQs: Answers to Your Specific Questions from Our Phone Lines

Can Covid-19 be transmitted through HVAC ductwork?

There has yet to be a scientific conclusion that the virus can be spread through air ventilation systems. There are many ideas currently circulation that you can add to mitigation procedures to reduce the potential spread of all pollutants within your home’s air conditioning system. HEPA high-efficiency filters are very capable of removing airborne viruses, bacteria, and other airborne debris from your home to promote improved indoor air quality.

The installation of a UV-C light technology or ionization-based air purification system will destroy airborne viruses and other pollutants. Increasing the humidity and airflow can deactivate and dilute airborne pollutants. Having routine maintenance on your air conditioning system that sanitizes your HVAC system components is extremely beneficial.

Are HEPA high-efficiency filters effective against the spread of Covid-19?

HEPA air filters can remove small particles, as small as viruses, from your airflow within your home. Although using a HEPA air filter can reduce Covid-19 transmission, it will not completely eliminate the risk. The Covid-19 virus is so small it has the potential to pass through some HEPA filters.

The downfalls of using high-efficiency filters are that they can restrict airflow due to their denseness and your HVAC system will run longer or more frequently. These HEPA filters do trap more debris, which also means that they will need to be changed more often, and with a cost that is many times double a regular filter, that can be expensive.

According to the National Air Filtration Association (NAFA): “In order for filters to have any impact on infectious disease transmission, the transmission has to occur through the airborne route, filters have to be properly installed and maintained in appropriate systems to treat recirculated air, and filters have to be appropriately designed for the building in which they are used. More importantly, in most buildings and in most situations, filters may be considerably less effective than other infection control measures including social distancing, isolation of known cases, and hand-washing.”

Will UV technology kill the COVID-19 virus?

UV-C light is used to kill and deactivate antigens, including viruses that can pass through filters and penetrate into your HVAC system. There are different types, including upper air and surface-cleaning UV disinfection systems.

According to ASHRAE (as reported in ACHRnews): “the germicidal wavelength can kill 90 percent of all microorganisms living on HVAC air ducts and evaporator coils, depending on wavelength intensity and length of exposure.”

It is important to note that although UV-C light technology has been successful in killing other strains of coronaviruses, it has not been proven to kill Covid-19. UV-C light systems can be expensive, so you will need to weigh the cost toward a benefit that may not be guaranteed.

Are Ionizers effective against Covid-19?

Indoor air filtration systems that use ionized hydrogen peroxide to remove HVAC system pollutants can be placed inside your air distribution system. These small units that can be placed just past the filters destroy pollutants that get through the filters.

How do humidity and ventilation affect COVID-19?

Preliminary research shows that increased indoor humidity can deactivate Covid-19. In winter months where ventilation is reduced and humidity can be between 20-40%, Covid-19 seems to thrive and live for longer periods of time. The increase of moisture in the air may damage the outer membrane of Covid-19 and reduce the likelihood of the virus to remain airborne.

ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers) also recommends increasing ventilation (adding more outside air) to dilute any particles that may be present. Here in New York City, that’s not always easily done if you can’t just open a window. However, there are HVAC solutions that can add more outside air to your space.

Should my air conditioning system be sanitized?

This is a practice for most comprehensive maintenance services that are recommended in the spring before your HVAC system enters in the summer rush of its use. Although we cannot guarantee that Covid-19 particles have remained, there is a benefit to clean condenser coils, your ductwork, and your system components. Cleaning your system makes it operate more efficiently, consume less power, and keeps parts in good condition.

Sanitizing your HVAC system components is a one-time event with no long term protection or to future exposure to Covid-19.

For more information about R.M. Mullinix or indoor air quality, schedule an appointment, or visit our indoor air quality information page.