Nearly half of Victoria's homes would slash energy and water wastage and cut bills under a $2.57 billion proposal backed by an alliance of social welfare and environment groups.
Calling themselves the One Million Homes Alliance, the collection of 11 groups estimates the average household's energy and water bills could be cut by $296 a year through a basic efficiency drive.
It could lower yearly greenhouse gas emissions by 2.38 million tonnes and save 32.5 billion litres of water a year.
The retrofit program would include installing insulation, energy-saving lightbulbs and dual-flush toilets, sealing cracks in walls and frames and replacing old fridges and freezers.
Priority would be given to the homes of concession card holders, pensioners, the disabled, low-income families and renters.
Environment Victoria chief executive Kelly O'Shanassy said a stand-alone program would cost the state government $514 million a year for five years.