HVAC and COVID-19 Frequent Questions

MSU Chemistry Building

How IPF has addressed building air quality

IPF staff, together with our partners in MSU Environmental Health and Safety, are closely following guidance from the Centers for Disease Control and Prevention (CDC), the U.S. Occupational Safety and Health Administration (OSHA), and the American Society of Heating, Refrigerating and Air‐Conditioning Engineers (ASHRAE) guidelines for ventilation and filtration.

According the CDC, COVID-19 spreads when an infected person breathes out droplets and small particles that contain the virus, which are then breathed in by other people or land on their eyes, nose or mouth. Properly run HVAC (Heating, Ventilation and Air Conditioning) systems help reduce the risk of viral spread but do not eliminate it. According to ASHRAE, HVAC systems that meet ASHRAE 62.1 standards or code at the time of their design provide adequate ventilation.

Being vaccinated against COVID-19 remains the best way to minimize the risk of infection. Find out more from MSU medical experts and from the state health department

Below are some of the changes IPF and EHS have made as part of the university's commitment of $1 million to upgrade classroom buildings.


  • Run systems with additional fresh air if available two hours before and one hour after occupancy.
  • Keep systems running longer hours, including 24 hours a day, for systems not controlled by the campus building automation system.
  • Disable demand-control ventilation (DCV) controls that reduce air supply based on temperature or occupancy.
  • Clean outside air intakes.


  • Upgraded building filters to a higher grade (MERV 11 to MERV 13) in systems that can accommodate them. Buildings with classrooms are being prioritized. 
    • Buildings that already use 100% outside air, such as lab buildings, do not need filter upgrades.
    • Installation of high efficiency filters has been done based on product availability in priority order of classroom, public spaces and then offices. As noted immediately above, laboratory air is not recirculated so upgraded filters are unnecessary. 
    • Room air purifiers have been added to these classrooms that are not mechanically ventilated
  • Extended system run times so that air is filtered for a longer period of time.

Temperature and Humidity Control

  • Maintain temperature and humidity as applicable to the infectious aerosol of concern. This will be done within the constraints of the existing building systems so we do not create uncomfortable working conditions inside facilities or create conditions that would promote the potential growth of mold.
  • Validating HVAC unit operation.

Installed Air Disinfection Devices

  • Air purification devices have been installed in areas of high respiratory activity and in clinical areas where infected patients may be.
  • Portable HEPA purification units have been installed in all naturally ventilated classrooms.

HVAC Frequently Asked Questions

What is IPF doing to increase outdoor air ventilation in my building?

IPF is following guidance from the Centers for Disease Control and Prevention (CDC), American Society of Heating, Refrigerating and Air‐Conditioning Engineers (ASHRAE), and U.S. Occupational Safety and Health Administration (OSHA) guidelines for ventilation.

IPF implemented the CDC’s ‘Interim Guidance for Businesses and Employers Responding to Coronavirus Disease 2019. IPF is also following the expert guidance of ASHRAE (American Society of Heating, Refrigeration, and Air Conditioning Engineers) through their Position Document on Infectious Aerosols

Using building mechanical system economizers and addressing under‐ventilated spaces, IPF improved indoor air conditions starting with classroom facilities. 

These facility modifications will be balanced with indoor space temperature and humidity conditions so we do not create uncomfortable working conditions inside or create conditions that would promote the potential growth of mold. This is part of a multi‐pronged approach to help manage the risk of COVID‐19 in spaces across the university where people are together for extended periods of time. 

What has IPF done to improve filtration in university facilities?

IPF is adding high‐efficiency filters, starting in buildings with classrooms, in accordance with the latest CDC and ASHRAE guidance. Some filters were already at or above the level recommended by ASHRAE and the CDC.

IPF is following the guidance of ASHRAE through the Position Document on Infectious Aerosols. This document identifies that the use of highly efficient particle filtration in centralized HVAC systems reduces the airborne load of infectious particles. As a result, ASHRAE’s recommendation, as well as the recommendation of the CDC, highlights the use of high‐efficiency filters. New filters have been installed in systems that can accommodate the improved filters without degrading the system's performance. 

What should I know about the air quality in my workspace?

The vast majority of MSU buildings have mechanical ventilation systems that provide nationally endorsed levels of air filtration and ventilation, helping reduce the spread of COVID-19. In older buildings that lack such systems, air purifiers have been installed in classrooms and other key locations.

It is worth noting that thousands of MSU employees and students have been working or living on campus throughout the pandemic.

Is my window air conditioner safe to use?

Using a window air conditioner in your space is safe to use. However, because air conditioners only recirculate room air and do not bring in additional outside air, ventilation quality is dependent on other factors such as additional mechanical ventilation to the space, or open windows or doors. 

What is being done regarding rooms that don't have windows or have windows that can't be opened?

No building adaptations are necessary for these spaces if the building is mechanically ventilated. Opening windows in a building that is air conditioned will cause the system to not operate correctly. No additional outside air is needed and additional air purification is not required.

Can you test my building's airflow or air exchange rates?

Additional testing is not required. Outside air ventilation requirements are set during the design process to meet code, and building systems are maintained in alignment with local code at time building was built.

Can departments purchase their own portable air purification units?

Yes, but there are few situations in which this expenditure would be beneficial or needed.

Does IPF have a list of portable air purification units they recommend?

IPF has reviewed many air purification units to ensure units have a good quality HEPA filter, seal and motor. A list is available here. The purifier should be sized correctly for the volume of the workspace.


IPF Communications