Ventilation and filtration provided by heating, ventilating, and air-conditioning (HVAC) systems can reduce the airborne concentration of the virus that causes COVID-19 (SARS-CoV-2), which can reduce the risk of transmission through the air.

Here are some suggestions from the CDC:

• Check to be sure your HVAC filter is correctly in place and consider upgrading the filter to the highest-rated filter that your system can accommodate (consult your HVAC manual or an HVAC professional for details).
• HVAC systems only filter the air when the fan is running, so run the system fan for longer times, or continuously.  Many systems can be set to run the fan even when no heating or cooling is taking place.
• When used properly, air purifiers can help reduce airborne contaminants, including viruses, in a home or confined space.
• Improve ventilation with outside air to improve indoor air quality:
  • Open the windows, or screened doors, if possible.
  • Operate a window air conditioner that has an outdoor air intake or vent, with the vent open.
  • Open the outside air intake of the HVAC system, if yours has one (this is not common).
  • Operate a bathroom fan when the bathroom is in use or continuously, if possible.
  • Avoid these actions when outdoor air pollution is high or when it makes your home too cold, hot, or humid.
• Care should be taken with portable ventilation equipment, for example, fans, to minimize air blowing from one person directly at another person to reduce the potential spread of any airborne or aerosolized viruses.
• Running your HVAC system, using an air purifier or a portable air cleaner, and increasing ventilation are not enough to protect from COVID-19. Continue to follow other prevention guidelines.
• Use of ozone generators in occupied spaces is not recommended. When used at concentrations that do not exceed public health standards, ozone applied to indoor air does not effectively remove viruses, bacteria, mold, or other biological pollutants.