One of the most effective methods of achieving savings in electrically-operated systems and increasing the efficiency is reactive power compensation. With the presently enforced regulation, compensation is mandatory for industrial consumers and it is done at certain power intervals, there is no regulation for residences and small scale enterprises on this subject. In this study, measurement of the reactive power in single-phase systems has been developed, as well as calculation for directing for energy saving through a microcontroller. In the implemented system, the phase difference between the current and voltage is measured, the outputs are made fuzzy according to the amount of the consumed reactive power and directing to saving is done Implementation results demonstrated that the designed system has a simple structure and small dimensions, it brings up the power coefficient of the system to the optimum level, it reduces the faults to minimum and reduces the cost. Furthermore, the portability feature of the system makes it possible to prevent adverse situations that may happen when no reactive power is consumed or when no device is being used. © 2010 AECE.