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Lessons from COVID-19 to increase the resilience of our office buildings

News | 08 Dec 2020

As the nation’s most widely used annual reporting tool, NABERS has been uniquely placed to observe the impacts that COVID-19 and its related building usage shifts have had on the environmental performance of Australia’s office buildings.

We moved quickly to ensure our rules remained fit for purpose over the pandemic. Hundreds of sites across Australia were able to complete a rating due to the flexibilities introduced in our Rules.

Six months later, let’s look at what the data has shown us using our COVID tracker dashboard.

In summary:
- NABERS Ratings remained valid and valuable despite the pandemic
- Water use and waste generation have been much more impacted by the number of occupants in a building than energy use
- Reduced occupancy levels create opportunities to educate occupants and manage waste to improve ratings
- An opportunity exists for better part-load and responsive energy management
- Disruption can lead to creativity and innovation


The most obvious impact of COVID-19 on our office buildings has been greatly reduced occupancy.

Google’s mobility data for the period shows fewer people travelled to and from work. This decline in workplace presence was more notable in major cities, home to most high-density, high-rise office buildings.

Google Mobility Data

Since July, occupancy levels are starting to rise again. The trend towards returning to normal levels persisted in most major cities through until November 2020.

Property Council of AustraliaSo, what does this variance in occupancy mean for resource consumption by our buildings? Let’s start with an easy one, water.

Office Water

There has been a pronounced decrease in water consumption as a result of low occupancy.

Office Water

A review of water bills provided for NABERS ratings showed that Office buildings across Australia have seen around a 63% drop in quarterly water bills when compared to a non-COVID-19 impacted quarter in 2019. However, note that this represents a drop during a single quarter, where occupancy was at its lowest point across Australia, rather than the whole year. And because our ratings use 12-months of water use, the impact of this temporary drop in consumption on NABERS Water ratings has been smaller than this may suggest.

This has translated to a 0.52 average star increase for office ratings with seven months of COVID impacted data.

Fewer people in offices means less heat rejection load on the air-conditioning systems, but also much lower potable water usage. This is a predictable relationship. But it is one of the first times in history we have been able to see what the results actually are when most buildings operate at very low occupancy. This insight creates opportunities for improvement strategies.

Key finding: the presence of occupants makes a major difference in water use in buildings.

As it will be unsurprising to many of you, occupants have shown to make a huge difference in water use during the pandemic. Water use dropped significantly when they weren’t there, and it is likely to return when they come back. This highlights the importance of focusing on the occupants when it comes to reducing water use, with a spotlight on the appliances they use and their behaviour.

“Buildings minus people equals savings” may seem like a straightforward and obvious conclusion, but we can say, at scale, that it is proved across buildings that usage of water has a strong relationship with the number of people in the building.

If that has wet your appetite for more insights at scale across the office sector, the energy insights we found will knock your socks off.

Want to learn more about how star ratings have changed?
Go to our COVID-19 data gallery page to break down this information by rating type state. This dashboard will be updated monthly going forward – be sure to look at the number of buildings being analysed. More recent months will have a smaller number of buildings included.

Office Energy

The relationship between occupancy and usage as seen in water was not as visible for energy consumption.

At the peak of the reduction in energy usage (April 2020), energy consumption was only down around 20 to 25 percent, which is drastically different from the 60 to 80 percent decrease we saw in occupancy.


We wouldn’t expect occupancy changes to be as big an impact on energy consumption as they did on water consumption. To begin with, if a building is operating, there are major energy uses that are independent of how many occupants show up on the day, such as lighting or ventilation for car parks.

Put simply, when lighting is provided for a meeting room, the light goes on whether there is one person or ten people in the room. There is also the fact that clauses in leases were not designed for a pandemic, and buildings had to continue to provide full services and spaces that were comfortable even when occupancy was at its lowest.

Even then, many of us thought we might be able to see a greater reduction in energy consumption over this time. Instead, at a time when occupancy across Australia was minimal, base building energy use in offices reduced by only 25%. Energy use has since begun to climb back up, as occupants have been returning to the workplace.

Having said that, this unique situation has unveiled an exciting opportunity in the evolution of more responsive energy efficiency and energy management. One that is especially relevant given the changing patterns of office space usage, where flexible working practices might translate into larger differences in occupancy from day-to-day.

A more flexible workforce will need more agile building management to match buildings that have the technology, lease clauses, and building management practices to provide energy-efficient, comfortable and healthy spaces.

Key finding buildings could be more responsive to changing occupancy.

As we move towards buildings with the balance of the rating period being impacted either by COVID-19 or by lower occupant density, we are expecting the impact on NABERS ratings to remain consistent with what we’ve seen so far.

In the latest NABERS Energy ratings, buildings have seven months of COVID-19 affected data. NABERS Energy star ratings across the country have seen an average improvement of around 0.14 stars (taking into consideration the 0.1 star improvement in an average NABERS Energy star ratings we see every year).

Want to learn more about how star ratings have changed?
Go to our COVID-19 data gallery page to break down this information by rating type state. This dashboard will be updated monthly going forward – be sure to look at the number of buildings being analysed. More recent months will have a smaller number of buildings included.

Office Waste

While the NABERS Waste data set of repeat customers is too small to confidently draw conclusions about star rating impacts, the impacts are likely to be much less than we have seen in energy or water. This is because the ratings are largely based on recycling rates. If the proportion of recovered material from total waste remains constant, Waste ratings are unlikely to change much with reduced occupancy.

We haven’t included Office Waste in the dashboard but couldn’t resist digging into what we saw throughout the lockdown.

The total amount of waste generated in offices has, of course, reduced. Much like in the case of water use, fewer people at their workplaces unsurprisingly resulted in less waste being created in offices. While predictable, this linear relationship reveals unexpected insights and considerations for the future.


Buildings using the NABERS Waste Platform gained greater visibility of their waste and were able to respond quickly to changes. For example, they scaled back waste servicing levels to reduce the frequency of their pickups, cutting out an unnecessary financial burden.

So, what does the future of waste look like with a similar number of people using the office, just not all at the same time?

Education work around waste avoidance and high-quality sorting should still be top of the priority list. Sorting materials well at the tenant level remains as important as ever as does the need for good signage and behaviour change programs. Reduced occupancy levels, in theory, should make it easier to monitor and manage tenant-level recycling, and to engage occupants around good use of waste management systems.

Key finding: monitoring waste production should be easier with reduced occupancy


In conclusion...

NABERS measures actual efficiency, not intention. For offices adapting to new ways of working, NABERS ratings remain valid as an independent and trustworthy way to prove and compare your sustainability progress.

The built environment is well poised to look for improvements in how we manage demand response for energy, water, waste, and adapt our strategies for occupant comfort. We all remain committed to creating the best spaces we can for the people who live work and play in our buildings.

NABERS is proud to have worked so closely with the Assessor community over the pandemic to deliver rules in record time and continue rating. Our next consultation paper will be released before the end of the year to ensure that the NABERS rating procedure continues to meet the needs of the built environment.

Want more? You can find out more about the insights contained in this article, and further details on our COVID-19 data gallery page.

Note: NABERS Ratings changes figures referenced are from 8 December 2020.