Molecular Structure of Virus

Do viruses spread through air conditioning

Keeping air-conditioned spaces safe for occupants is a primary concern for building owners, managers, and services contractors.

There is currently no evidence of human infection with SARS-CoV-2 caused by infectious aerosols distributed through the ventilation system ducts of air conditioning systems. The risk is rated as very low.

There has been a lot of discussions recently regarding the airborne spread of COVID-19. One view is that the virus is spread contained in large respiratory droplets that quickly sink to the ground when expelled from the infected subject. More recently evidence has been building to support the theory that the virus is spread in micro particles that remain suspended in the air for longer periods of time.

Studies of clusters where indoor transmission occurred point to the role of the air conditioning system in moving the air from the infected person to others in the room.
The risk is higher in spaces where there is a high density of people. Also, in situations where singing in groups or group worship with singing, chanting, or talking at volume is involved.

What does this mean for those of us that rely on air conditioning systems to provide a healthy and comfortable living environment? Do not reach for the off switch and suffer, there are ways to keep safe in an air-conditioned environment.

Here are a few things you can do to ensure the hygienic operation of your air conditioning system. These tips will ensure you have done all you can to protect those who live and work in the air-conditioned space:

  • Ensure the systems are maintained on a regular basis. We recommend a three-month cycle for comfort systems.
  • Maintenance should identify the soiling of the filters and components within the system and clean where necessary.
  • Maintenance should ensure filters are in good condition and fitted correctly so there is no air by-pass.
  • Maintenance should be carried out as per NZS 4302:1987 Code of practice for the control of hygiene in air and water systems in buildings.
  • Ventilation of the space and has been identified as a key component to reducing infection. Higher risk air conditioning systems recirculate the air in the space without adding outdoor air.
  • Checking and increasing ventilation rates will reduce transmission risk and can be identified during maintenance.
  • Reduce the density of people in the space, observe the social distancing guidelines for offices. Reduce contact time if work in proximity cannot be avoided.

Some systems can be upgraded to include superior filtration such as High-Efficiency Particulate Air (HEPA) filters. Ultraviolet lamps can be installed inside the ducting of some systems to sterilise the passing air.

If you have any concerns regarding the cleanliness of your air conditioning system just call Thermo Tech on 0800-177777 and ask for a maintenance.

The source of some of the information above came from the following:

COVID-19 likely to be airborne, claim 239 experts.

‘Watching brief’ on airborne COVID-19

HVAC & Infectious Diseases

Heating, ventilation and air-conditioning systems in the context of COVID-19



Leave a comment

Hey, so you decided to leave a comment! That's great. Just fill in the required fields and hit submit. Note that your comment will need to be reviewed before its published.