AbstractThis paper presents a design and construction of measuring system to measure the power consumption of a split type air conditioning unit and refrigerator in household for energy conservation without having to install any instrument directly to appliances. The system will be only using aggregate power consumption data from only one instrument installed at main power distribution board and using proposed algorithm to disaggregate power consumption data of selected appliances, it is called Non-Intrusive Load Monitoring (NILM). It can significantly reduce cost and time in home energy audit. In this paper authors have used 3 points of monitored data to detect any change of power signal that obtained a 1Hz sampling rate of active power from energy meter. The proposed method uses basic knowledge about specified air conditioning and refrigerator to establish criteria of disaggregation. Significant saving in air conditioner and refrigerator energy consumption can be achieved by real-time information on their in use. The results showed that the proposed system can disaggregation energy of air conditioner in accuracy 90.71% and refrigerator in accuracy 89.95% from total consumes energy.