Monitoring Systems and the Internet of Things have become increasingly important, among others, in Renewable Energy applications. A combination of measuring sensors and actuators controlled and processed by an intelligent central system is necessary to reduce energy consumption automatically. This paper develops a modern concept for a Smart Energy House. The functionality and the hardware implementation are explained in detail based on a concrete simulation of the self-refilling water tank. The system comprises various separate located IoT modules integrated with a central host using TCP/IP network infrastructure, as well as communication technologies and protocols, such as WiFi and MQTT. Those sensors, also called clients, are wireless devices designed to measure different environmental conditions, such as temperature and humidity, in real-time. Changes in the current water level and battery charging progress are also being monitored. The host consists of three parts: storage service, web-based monitoring platform, and program logic for decision-making methods. Most of the processes, such as electrical control, data collection, information query, and analyzing functions, were implemented using Python libraries and self-written algorithms. An essential part of an intelligent home monitoring and automation system is secured remote accessibility and maintenance in any emergency. Therefore, the system supports both local and remote access. Data visualization and alarming routines are implemented within the web-based free software “Grafana” combined with the time-series database “InfluxDB”. Finally, the results demonstrated in this article show that the system has excellent application prospects due to its stability, low cost, high performance, user-friendly and customary configuration. The concept has been improved and prepared for the Smart Energy House test object located in Berlin.