Wollongong City Council hopes to boost its environmental credentials and save ratepayers money after its Burelli Street headquarters became one of Australia's first existing buildings to register for a green star rating.
The rating system was started by the Green Building Council of Australia (GBCA) in 2003 and is usually used to assess new buildings against a range of environmental criteria.
There are just 14 existing buildings, including offices, shopping centres, schools, art galleries, industrial premises and libraries, under assessment.
Lord Mayor Gordon Bradbery said the council decided to apply for the rating to reduce its carbon footprint and find extra savings as part of its financial sustainability review.
"We want to highlight the fact that an existing building - even one that was built in the mid-80s - can change to be more sustainable and it doesn't just have to be new buildings," he said.
"And it will save the ratepayers money and takes the pressure off our budget because of the electricity and water savings."
Cr Bradbery said the council had already installed environmentally friendly upgrades including rainwater harvesting, dual flush toilets, low water urinals, low flow taps and sensor taps in public areas.
It also put in a new heating ventilation and airconditioning system, heat-reflective blinds and lighting upgrades, which helped to reduced energy consumption by 35 per cent and water consumption by about 50 per cent since the 2008-09 financial year.
GBCA will assess the building against nine categories, including energy, emissions, indoor environment quality, water, transport, land use and innovation before a green star rating can be awarded.
One star represents "minimum practice", while six represents world leadership.