Energy usage estimation device and energy usage estimation method

An energy usage estimation device comprising:

• a power measure that calculates, based on a current and a voltage measured at a predetermined location in a power supply line, active power and apparent power for each predetermined time period based on utilization of plural kinds of electric facilities connected to the power supply line;
• a data memory that accumulates and stores data regarding the active power and the apparent power calculated by the power measure in a time-series manner;
• a variation detector that analyzes data regarding the active power by what corresponds to a predetermined time period and stored in the data memory to obtain, at a predetermined time interval, an active power difference that indicates a variance of the active power and detect, based on the obtained active power difference, a time slot at which there is an operation change in any one of the electric facilities;
• and
• a distribution estimator which calculates, when the variation detector detects the time slot, a power factor in the time slot, and which estimates power consumption for each kind of the electric facilities in the time slot based on the calculated power factor and a threshold set in advance for each kind of the electric facilities.