Australians should start thinking of buildings as producers not consumers, given the pace of efficiency gains over a decade of voluntary Green Star ratings, an industry expert says.
Electricity generation, water harvesting, even food production may become commonplace in commercial buildings as owners battle with rising energy costs and seek to minimise environmental impacts, said Robin Mellon, chief operating officer of the Green Building Council of Australia.
That such steps can also save money will spur further change.
"We're now at the stage where we're seeing public and private sector projects achieving a four- and sometimes a five-star Green Star rating, and not costing a dollar more," Mr Mellon said. "You need good design, good technology, good construction and then good behaviour to hit that sweet spot."
Mr Mellon's confidence is stoked by the Green Building Council's review of the first 10 years of ratings. A survey of 428 Green Star-certified projects across all states and territories has revealed major savings in material use and greenhouse gas emissions that are both "exciting and reassuring", Mr Mellon said.
Compared with average Australian buildings, the certified projects produced 62 per cent less greenhouse gas and used 66 per cent less electricity, the report found.
The cumulative emissions savings amount to 625,000 tonnes of carbon dioxide a year, or the equivalent of 172,000 cars being taken off the roads.
Average certified buildings also used 51 per cent less potable water than the typical equivalent, or enough to fill 1300 Olympic-sized swimming pools a year.
Perhaps the most outstanding result, though, was the finding that Green Star buildings recycled 96 per cent of their construction and demolition waste, saving some 37,600 truckloads of waste otherwise bound for landfill.
"That is better than any other country is doing," Mr Mellon said.
The advance of the recycling industry is echoed in other markets. A decade ago, low-toxicity paint with low levels of volatile organic compounds would have been tough to find. "Now it shouldn't cost any more" than standard paint, Mr Mellon said.
Co- and tri-generation equipment and chilled beams have also become much more readily available and therefore more cost-effective. Similarly, a decade ago, carbon-neutral buildings were seen as "a blue sky goal", Mr Mellon said. "Now we have them in operation."
Examples include the Pixel Building in Melbourne and Perth's Katitjin Centre. New sustainable standouts in Sydney include 1 Bligh Street, the city's first six-star building, which recycles 90 per cent of its waste water.
While the savings in materials and energy can be readily gauged, the benefits for office staff of improved indoor environments - and the resulting higher productivity - are only now being realised. Mr Mellon predicts the Green Star ratings will be further extended into hospitals and schools.
"There is no excuse for treating patients or educating children in less than best-practice environments," he said.
And while developers and prospective owners may gripe over the extra costs to achieve high Green Star ratings, other studies indicate poor design and construction can end up costing as much as 25 per cent more.
Appropriate orientation of the building, passive shading and maximising natural ventilation should all feature in the design.
"Can we afford not to do this?" Mr Mellon said.