Development and User Acceptance Evaluation of a Low-Cost IoT-based Electricity Monitoring Dashboard for Homes and Small Offices

Abstract

Limited access to integrated, real-time electricity monitoring leaves homeowners and small-office managers with insufficient information to manage electricity consumption effectively. Monthly utility bills provide only a rearview-mirror summary of consumption, making it difficult to identify which appliances, routines, or time-of-day habits are driving costs higher. This study aims to develop and test a low-cost, IoT-based electrical monitoring dashboard for homes and small offices using ESP32 microcontrollers and Home Assistant. The sensor readings are sent wirelessly via Wi-Fi to a locally hosted Home Assistant instance, and a template sensor converts the accumulated kilowatt-hours into a live electricity cost estimate using the Malaysian domestic tariff of RM 0.220 per kWh. The dashboard shows current voltage, current, power consumption and historical consumption graphs. We conducted a User Acceptance Test to assess the proposed system's usability with 50 participants selected through convenience sampling. Moreover, we did not divide participants into groups; all evaluated the same system using the same questionnaire. The results indicated that participants valued the ringgit-based electricity cost information and reported that it helped them better understand their electricity consumption and energy-saving decisions. This study's main contribution is integrating real-time electrical monitoring, historical visualisation, automated cost estimation, and threshold-based notifications into a low-cost, locally hosted dashboard for household and small office users. The evaluation also identified shortcomings in cross-device responsiveness on mobile screens and intermittent dashboard delays when Wi-Fi networks are congested. These areas, along with the requested CSV export feature, guide future development.