Do HVAC Filters Help with COVID-19?

Learn how portable air filters and HVAC filters can help reduce indoor air pollutants including viruses found in the air and how they can help protect people from COVID-19.

Do HVAC Filters Help with COVID-19?

Portable air filters and climate control filters can help reduce the amount of indoor air pollutants, including viruses, present in the air. However, on their own, these filters and HVAC filters are not enough to protect people from the virus that causes COVID-19. Recent advances in filter design and manufacture have decreased the pressure drop and its effect on HVAC operations, but not all filters have adopted this new technology. Appliances that use HEPA filters only work when turned on, so you may need to run your oven fan continuously or for longer periods of time. Viral RNA has been detected in return air grilles, return air ducts, and heating, ventilation and air conditioning (HVAC) filters, but this does not necessarily mean that the virus is capable of transmitting the disease.

Additionally, if a high concentration of CO2 causes an increase in air flow to a room, that air can be “stolen” from other rooms in the same HVAC system. To meet the European standard, a True HEPA filter must capture at least 99.95% of particles 0.3 microns in size. One way to improve the air quality in your home is to upgrade the filter in your HVAC unit. Therefore, a filter with a MERV rating of at least 13 would be effective at capturing COVID-19 virus particles and could help reduce the spread of COVID-19 indoors.

UVGI HVAC air disinfection systems usually require more powerful UV lamps or a greater number of lamps, or both, to provide the UVGI needed to deactivate pathogens in a short period of time. A True HEPA filter is certified to capture at least 99.97% of particles 0.3 microns in size by DOE standards. Although a NASA study showed that HEPA filters can stop particles as small as 0.1 microns, which is approximately the size of the coronavirus, other direct investigations are limited and the official US classification system specifies their effectiveness only for 0.3 micron particles. It is too early to draw any conclusions about implications for HVAC systems associated with these findings. Because outdoor air flowing into an HVAC system can be polluted, especially in metropolitan areas where buildings are close together, technicians sometimes install a pre-cleaner for incoming air.

HEPA stands for high-efficiency particulate air and is a highly absorbent media filter that meets HEPA standards. The filter does not actually kill the virus but it is capable of capturing the type of material that a virus or bacteria need to survive, such as mucus or saliva. Only some air conditioners can accommodate HEPA filters and technicians must configure them correctly and replace them regularly.