This article shows an evaluation of a ToU network tariff test on Australian domestic electricity customers. The test was with 444 domestic electricity customers in Tasmania, Australia. This Australian case has international implications for energy policy and regulation. Australia has the world’s highest domestic PV (photovoltaic system) adoption and combining this with high air-conditioning and water heating load leads to high diurnal variation and an emerging issue globally. Related issues include over-voltage. Thermal overload, frequency instability and voltage instability. The method was a statistical analysis of the energy use patterns using k-means clustering, and then stepwise regression to find drivers of energy reduction behaviour. There were also tests on the effect of weather and seasonal effect. The conclusions are that there was strong response from 4% of customers, and moderate response from 15%. There was a stronger response in households that were drawing more electricity and were wealthier than the average households.