The City of Sydney has published findings that show the council expects to save $1.3 million a year by overhauling the energy and water performance of major buildings.


Sydney Lord Mayor Clover More said the $6.9 million project is a major step towards accomplishing the city’s carbon reduction targets.


"Retrofitting the City's buildings with energy and water efficiency technologies will significantly reduce our costs - in fact, the project will pay for itself within six years," the Lord Mayor said.


"It will also cut 7000 tonnes of carbon emissions a year, taking the City's overall emissions reductions from 6.8 per cent to 19.9 per cent - well on the way to our target of 70 per cent by 2030 (on 2006 levels)."


The program will retrofit 46 of the City's major buildings, including Town Hall House, the Woolworths building, Customs House, pool centres, community centres, libraries and car parks.


They will be fitted with energy efficient lighting, air-conditioning and heating, centralised power management systems to reduce energy consumption by computers depending on activity, and voltage reduction units to slash electricity use in pumps, fans and lights.


The retrofit will cut energy use by 7.5 million kilowatt hours (kWh) a year, saving $840,000 a year. Water consumption will fall by 61,360 kilolitres a year, saving $200,000 a year. The retrofit will also reduce maintenance costs and avoid $160,000 in carbon pollution costs.


After a tender process, the Council has approved Origin Energy to carry out the work. To make sure the targets are achieved, the contractor has to design and install the systems and guarantee the reductions. The energy and water performance guarantees will be independently verified.