The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) has published two statements to define guidance on managing the spread of SARS-CoV-2, the virus that causes COVID-19 disease (coronavirus) with respect to the operation and maintenance of heating, ventilating and air-conditioning systems in buildings.

“In light of the current global pandemic, it’s critically important that ASHRAE responds with guidance on mitigating the transmission of the virus, as well as ventilation and filtration recommendations,” said 2019-20 ASHRAE President Darryl K. Boyce, P.Eng. “ASHRAE has a significant role to play in ensuring safe and healthy building environments and these statements offer the expert strategies needed at this time.”

ASHRAE developed the following statements in response to widening false statements surrounding HVAC systems. ASHRAE officially opposes the advice not to run residential or commercial HVAC systems and asserts that keeping air conditioners on during this time can help control the spread of the virus. The official statements are below.

ASHRAE’s statement on airborne transmission of SARS-CoV-2/COVID-19

Transmission of SARS-CoV-2 through the air is sufficiently likely that airborne exposure to the virus should be controlled. Changes to building operations, including the operation of heating, ventilating, and air-conditioning systems, can reduce airborne exposures.

ASHRAE’s statement on operation of heating, ventilating, and air-conditioning systems to reduce SARS-CoV-2/COVID-19 transmission

Ventilation and filtration provided by heating, ventilating, and air-conditioning systems can reduce the airborne concentration of SARS-CoV-2 and thus the risk of transmission through the air. Unconditioned spaces can cause thermal stress to people that may be directly life threatening and that may also lower resistance to infection. In general, disabling of heating, ventilating, and air-conditioning systems is not a recommended measure to reduce the transmission of the virus.

HVAC filters, along with other strategies, help to reduce virus transmission while removing other air contaminants that may have health effects.

ASHRAE’s Environmental Health Committee also developed an Emerging Issues Brief to support the two above statements:

There is great concern about the real possibility of transmission through the air of various pathogens, especially SARS-CoV-2, among staff and administration in healthcare facilities, office workers, retail workers and patrons, manufacturing workers, and residents in private and public facilities and the general public in outdoor settings and in public transportation.

ASHRAE has created the Epidemic Task Force, comprised of leading experts to address the relationship between the spread of disease and HVAC in buildings during of the current pandemic and future epidemics. The ASHRAE Environmental Health Committee’s Position Document Committee also updated a Position Document on Infectious Aerosols.

“ASHRAE, working with its industry partners, is uniquely qualified to provide guidance on the design, operation, and maintenance of heating, ventilation, and air-conditioning systems to the COVID-19 pandemic as well as to prepare for future epidemics,” said ASHRAE Epidemic Task Force chair, ASHRAE Environmental Health Committee voting member and 2013-14 ASHRAE Presidential Member Bill Bahnfleth.

The newly updated ASHRAE COVID-19 Resources webpage is available at www.ashrae.org/COVID19. The page includes frequently asked questions and the latest information on the ETF’s guidance for healthcare facilities, residential buildings and other issues related to the COVID-19 pandemic.