A method for estimating load by energy meter including a load estimation model based on a neural network includes steps of: (a) the energy meter generating sampled supply electric power information by sampling information on electric power based on a predetermined sampling rate; (b) the energy meter instructing the load estimation model to output load information; and (c) the energy meter (i) transmitting the load information and information on an amount of the electric energy to a data management server and (ii) instructing the data management server to monitor the information on the amount of the electric energy, information on each sub-electric power for each of the loads, and information on each sub-amount of the electric energy for each of the loads.