At the start of 2022, City of Melbourne conducted an innovative world-first research project which found that straightforward changes to ventilation systems can significantly decrease the transmission of COVID-19 and reduce energy consumption in office buildings.
The BREATH pilot tested and evaluated three different ventilation systems in a vacant CBD building over three months: displacement ventilation air conditioning, in-ceiling air filters and natural airflow through open windows.
Until now, office building managers have been making efforts to reduce COVID-19 transmission by opening windows to maximise ventilation, increasing air change rates, adding filtration and flushing air through the building. However, these actions can all increase energy consumption, cost more and compromise comfort.
Our pilot tested alternative methods of achieving the same outcomes.
The BREATH pilot project found:
- All three ventilation systems reduced the potential transmission of airborne viruses when compared to mixed ventilation, improving safety for office workers.
- Displacement ventilation air conditioning which supplies air from floor level - was the most effective and energy-efficient system tested, reducing COVID-19 transmission by 83 per cent, while also reducing energy consumption by 20 per cent.
- Displacement ventilation is the most expensive to install, but there are no additional ongoing maintenance costs.
- In-ceiling air filters reduced virus transmission by 49 per cent but resulted in a minor increase in energy consumption.
- Opening windows reduced virus transmission by 53 per cent, but increased energy use by up to 20 per cent with seasonal temperature variations.
- Opening windows is not available to all office buildings and is not a viable solution due to Melbourne s climate.
The BREATH pilot project was led by City of Melbourne and delivered in partnership with Cbus Property, University of Melbourne, AG Coombs, SEED Engineering and Westaflex, with peer review by AURECON.
