More than a decade of incremental improvement has created a major turnaround for an office building in Melbourne from “the cheapest box you could make to put people in”, to one that is now an example of major sustainability, and will be part of Sustainable House Day on Sunday 16 September.

How do you turn a dreadful 1980s era tilt slab concrete office building into a showcase of zero carbon commercial office space?

According to Dr David Collins, owner of Positive Energy Places on Melbourne’s 490 Spencer Street, continuous and “opportunistic” improvement, with a focus on eradicating carbon emissions is key.

Collins is the managing director and principal engineer at Synergetics Consulting Engineers, which moved into the building as tenants in 2003.

From the get-go the company was looking to make the space more environmentally sustainable. The then owner of the building was supportive of the goals, and in 2005 offered to sell them the property. So Collins bought it.

The ongoing improvements, he says, make the building a “living lab”.

“Every energy efficiency improvement started as an experiment.”

As engineers, the approach to upgrading the building and its performance was based on “harnessing nature”.

“We take advantage of natural forces we call the ‘gravity’ in how we do things,” he says.

That means prioritising the simple, low-cost or no-cost solutions.

That meant leveraging passive heating and cooling. The concrete of the structure is used to store energy – retaining heat in winter and coolth in summer.

The plate-glass single-glazed windows were an issue, so blinds and other shading were introduced to keep the sun off the glass. The building is now best known for its unique recycled public artwork that covers its facade and provides external shading from the western sun. Reflective foil insulation was added to the roof of the two-storey building, and glass wool to critical walls.

Repurposed materials were used extensively. For example to refurbish the foyer, timber from pallets was used to cover the glass fibre insulation. The whiteboard is repurposed brown wrapping paper.

Collins says an initial whole building NABERS rating in 2008 came in at 3.5 stars and 100 per cent Green power took it up to 5 Stars.

The aim was always to be a carbon neutral building, a huge challenge for a basic building envelope.

Initially, it was necessary to purchase offsets to achieve carbon neutrality, “which we were keen to  avoid as many people question their credibility”, Collins says.

”The ultimate credibility is a positive energy building with onsite renewable energy generation greater than building consumption.”

The decision was made to install solar PV on the roof. A combined 24kW was installed in two tranches.

The result is the building now generates more energy than the occupants use. The excess is fed into the grid and makes a profit for the owner.

Positive Energy Places ensures commitments from tenants by only signs on businesses committed to being zero carbon enterprises.

The first tenant was the Energy Efficiency Council, which is still there a decade later. Others include Melbourne’s deputy mayor, Aarron Wood’s business, Kid Teaching Kids. Collins says tenants have a tendency to stay on: the newest tenant moved in about three years ago and only limited vacancies available for lease.

An average of 30 people work in the space on any given day.

Collins says his business is now keen to attract investors to create a positive energy building movement

Unlike co-working spaces that take a “battery hen” approach to the layout, workspaces are organised in “pods”, Collins says.

This gives each separate organisation more space and greater privacy.

David Collins [left] outside Positive Energy Places, photo Phoebe Powell


The building has no parking for tenants and when proposals were made to Melbourne City Council that cycle parking along Spencer Street would be a good thing, council responded by putting cycle parking in front of the building. There are now 14 bike parking spots and the building is close to trains, trams and buses.

Shared facilities include breakout rooms, meeting rooms, boardroom, rooftop deck and an electric vehicle, initially sourced as part of Victorian Government Electric Vehicle Trial. After the two-year trial finished, Mitsubishi offered the vehicle as a permanent asset.

Use of the car beyond short trips is one of the few extras tenants pay for. There are no costs for energy use, because there are no costs for energy for the whole building, Collins explains.

There are charges for printing costs, because the aim is to discourage unnecessary printing, and telephone calls, but that’s it.

When asked if the lack of bills is a factor that attracts and retains tenants, Collins says no – the attraction is zero carbon. He says the federal government is getting it wrong when it focuses on energy bills as the issue. Our big issue is carbon, he says.

“Our tenants find the building useful because it being zero carbon aligns with their own business ethos.

“They want to be part of the zero carbon journey.”

The building is throwing its doors open as part of Sustainable House Day on September 16 to share its journey with the broader community. Collins says he joined the program because defining people by the homes they live in is not the whole answer.

“If everyone took personal accountability and lived in zero carbon homes, and worked for zero carbon businesses, ate zero carbon food, and used zero carbon transport – we wouldn’t have a global GHG [greenhouse gas] problem.”

A background that goes back to the 1200 Buildings Program

The building was one of the founding members of Melbourne City Council’s 1200 Building Program, and a close relationship with Council has been part of its journey.

The state government has also taken an active interest in the building and its showcase initiatives, and is currently working through the possibility of a grant through Sustainability Victoria testing treatments for the plate glass windows and strategically placed operable windows for natural ventilation.

Because the windows are eight metres above the ground and the building quality is poor and retrofitting is a difficult and expensive proposition, the building relies on an energy efficient heat recovery ventilation system and air filtration.

A culture of sustainability – tenants engage with one another

Another important element of the building’s operation is the engagement of the tenants. Collins says that there is a culture of people having a conversation with others if they see energy or water being wasted.

“We try to avoid having signs and things like that,” he says.

In addition to influencing the staff working for businesses within the building, Collins says the sustainability approach has also influenced neighbouring businesses such as Fort Knox Storage and Joe Arcaro Architects.

Do we need a new model for measuring positive energy buildings

At attempt was made to obtain a new NABERS rating, but an expert from Deakin undertaking the audit told Collins that a positive energy building simply does not fit the NABERS model.

“It is like trying to measure apples by measuring oranges,” Collins says.

“There is a need to invent a new criteria. NABERS is great if you are interested in efficiency, but a different metric is needed if you are looking at producing energy above what you consume.”

It is a metric that is easy to measure, Collins says. Just look at the energy bills.

See here for details of Sustainable House Day on Sunday 16 September.

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