Provided is a network system. The network system includes: at least one unit selected from an energy receiving unit receiving energy and an energy management unit managing the energy receiving unit. An energy usage amount or energy usage rate of the energy receiving unit is adjusted; an energy usage amount or usage rate when the unit is controlled based on information relating to at least an energy rate is less than that when the unit is controlled without the base of information relating to at least an energy rate; the energy receiving unit comprises a plurality of components; and an operation of one component among the plurality of components is controlled based on the energy rate related information.