How do you upgrade a building’s NABERS Energy rating from zero to five stars? Bowen Investments has made a commitment to do just that and has some secrets to share.
Built in the 1990s, 5 Bowen Crescent in Melbourne had been the headquarters of Tabcorp for decades. But with the lease set to expire, and with the surrounding St Kilda precinct evolving rapidly, Bowen Investments, under the visionary leadership of Managing Director John Bergamin, decided to embark on an ambitious and forward-thinking upgrade.
“Tenant expectations of the workplace have changed. In a difficult, post-Covid office market, we needed a point of difference,” John says. “So, we engaged the best team, including Bates Smart architects and the Arup sustainable building team, and we set a goal to upgrade the building from a zero to five star NABERS Energy rating.”
Tabcorp, with 24/7 online gaming facilities, had energy hungry servers running around the clock. This had an eye-watering impact on energy consumption and went a long way to explaining the zero star NABERS Energy rating.
But by digging much deeper, Jason Yang, Arup’s Senior Sustainable Building Design Consultant, found a host of energy efficiency measures that would elevate the building to a market-leading 5 star NABERS Energy rating.
View the case study here: 5 Bowen Crescent, Melbourne VIC
More than a makeover
5 Bowen Crescent’s makeover will be “magnificent,” but the upgrade is far more than aesthetics, John emphasises. “There is no point investing so much money into this project – which we are – if we have a zero star NABERS rating. We knew we had to upgrade the services.”
But why a 5 star NABERS Energy rating? Detailed market research confirmed that pursuing 5 star NABERS would be worth the expense. A typical existing premium building, as defined by the Property Council of Australia’s Guide to Office Quality, would target a 5 star NABERS rating. “That was a good reference point for us,” Yang says.
“We looked at all the buildings within 5 Bowen Crescent’s postcode and found, by achieving a 5 star NABERS Energy rating, we were putting our building at the top level for energy efficiency. This certainly makes it stand out.”
- Bowen Investments has signed a NABERS Commitment Agreement to achieve a 5 star NABERS Energy rating – an increase from zero stars in 2021
- When compared to a “minimum intervention”, the 5 star NABERS Energy rating will achieve:
- 40% reduction in base building greenhouse gas emissions
- $50,000 annual savings in base building energy costs
Moving past minimums
Arup’s study considered ‘minimal’ interventions, which would use the existing base building systems but install more sub-meters to separate tenants and base building services. This scenario would achieve a 4.5 star NABERS rating. But that half star gap can be deceptive. “It represents just 10% star-wise, but energy-wise it’s between 30-40%,” Jason notes.
Arup then analysed and prioritised a range of energy improvement interventions to boost the building’s predicted NABERS Energy rating to the coveted 5 stars. These interventions included upgrading lifts, lights and boilers, installing photovoltaics on the roof, improving the efficiency of carpark ventilation and introducing wider thermostat setpoint ranges.
Compared to minimum intervention, these investments are expected to reduce the base building’s greenhouse gas emissions by at least 40% and represent an energy saving of $50,000 annually.
“From a technical point of view, the NABERS Commitment Agreement process is another layer of review which confirms our modelling process is robust and reliable. It gives us the confidence going into construction and operation that this building meets the requirements of a 5 star NABERS Energy rating with a sufficient buffer,” Jason adds.
We are seeing more and more councils require NABERS as a minimum requirement to demonstrate compliance with the National Construction Code and other best practice benchmarks. Having a NABERS rating shows a council that the building is future proofed.
Beyond box ticking
The City of Port Philip, the local government responsible for planning policy in St Kilda, requires developments of this type and scale to use the Built Environment Sustainability Scorecard, or BESS, to demonstrate they will meet best practice sustainable design, rather than the minimal energy efficiency standards outlined in Australia’s National Construction Code.
But a 5 Star NABERS Energy rating exceeds the benchmarks in both the National Construction Code and BESS, and a NABERS Commitment Agreement is one way that a project team can demonstrate leadership in energy efficiency, Jason says.
“We tick all the boxes in BESS and the National Construction Code, but NABERS is more rigorous than both.”
A NABERS Commitment Agreement ticks council planning boxes, but that wasn’t our driver. If council had been satisfied with a 3 star NABERS Energy rating we would have still pursued our goal for 5 stars. We want to differentiate our building in the market to attract high-quality tenants.
Green is the new black
So, beyond compliance and certificates, what can tenants expect of the reimagined 5 Bowen Crescent?
There will be a more dynamic and accessible lobby, stronger connections with the street and decorative rainscreens which gives the building a whole new identity.
A dedicated entry for cyclists will take them to bike parking and spectacular end-of-trip amenities. The basement floor is being transformed into a wellness centre, while the rooftop terrace will offer fresh air, natural light and views of nature.
High performance glazing and insulation on the building’s new rooftop spaces will enhance energy performance while photovoltaics will offset energy consumption. Retaining around 90% of the existing building will also save considerable carbon emissions when compared with new construction.
“We want to put our building in a position where it is ahead of its time. People will want to come to work at 5 Bowen Crescent because it’s attractive, and because it is efficient, healthy and sustainable,” John concludes.
“We think green is the new black. That’s what people are after. And this is why a high NABERS rating is important.”
View the case study here: 5 Bowen Crescent, Melbourne VIC
Existing buildings are in competition with new buildings to attract new tenants. But we are seeing a changing mindset among tenants. Tenants are looking for a high-quality building, not necessarily a new one. A high-quality building is one that aligns with a tenant’s sustainability targets.