A method includes: inputting information indicating power usage corresponding to each of the plurality of user IDs; generating a differential value between i) a first cumulative value of power usage corresponding to a first user ID and ii) a second cumulative value of power usage corresponding to a second user ID in a prescribed period; generating a first conversion value by converting the differential value to a use time of a first electric home appliance among electric home appliances corresponding to the first user ID; generating display data indicating that the differential value corresponds to the first conversion value; and transmitting the display data to an information terminal device corresponding to the first user ID.