Accuracy Comparison of Present Low-cost Current Sensors for Building Energy Monitoring

Reducing energy consumption in building is an important motivation for building energy monitoring and management system. In this work we focus on AC current measurement for small to large appliances such as air conditioners. Today's market has many low-cost AC current sensors that use different technologies and come with different usage convenience. This paper aims to compare AC current measurement accuracy for four low-cost current sensors in nowadays market. They are ACS712, WCS1800, SCT013, and PZEM004T. We also discuss about their price and difficulty of installation. We use ESP32 wifi-microcontroller to process measurements. We perform the test using AC loads in small steps from zero up to 20 A. Our results show that PZEM004T gives the best performance among these sensors. However, ACS712 is the best value current sensor because of its low price and performance, although it is more difficult on installation.