A new subsidy aims to entice businesses to light their buildings more efficiently.
The Energy Efficiency and Conservation Authority says lighting in all commercial buildings accounts for about $200 million worth of energy each year.
EECA's lighting programme manager Bill Brander says overall tens of millions could be saved by changing fittings and lighting controls.
He says a typical floor in a large commercial building could save $5000 a year from improved lighting and lighting controls with a pay back of under three years.
Mr Brander says while individual businesses will have to pay a few thousand dollars to go green, EECA is investing about $4 million in subsidies in 2012.
''We're partially subsidising the cost of controls and we're expecting that over the lifetime of the energy savings, to save the amount of energy used in a large suburb.''
Mr Brander says that represents the energy use of 3000 households.