In this study, we explore the use of IoT devices, specifically ESP32, to record current, voltage, and electrical power data in a multifan system. The data reading speed of ESP32 is sufficient to read both voltage and current sensors, enabling the acquisition of the waveform signal. From the waveform data, the magnitudes of current, voltage, and power can be accurately determined using a reliable calculation technique. This application still needs calibration to ensure accurate values. Calibration can be done by adjusting the root mean square value and phase of the measured signal. In a multifan system controlled by a dimmer, the current is not always a sine wave. The total power of four fans with the same total speed is lower than the power of one fan with the same speed. The measurement results indicate that the values for current, voltage, power, and power factor are highly accurate, with a correlation coefficient of 0.99.