The article presents an integrated energy management solution for solar-powered smart buildings, combining a physical system with advanced IoT and cloud-based control systems. The physical system includes a heat pump, photovoltaics, solar thermal panels, and an innovative low-enthalpy radiant wall and ceiling, providing self-sufficient heating and cooling. The control system uses Modbus, HTTP, and MQTT protocols for seamless interconnectivity, monitoring, and remote management. The solution was successfully implemented in a model house in Paris and a deep energy retrofit of a single-family house in Oviedo, Spain, demonstrating increased energy efficiency, improved thermal comfort, and reduced environmental impact. The system integrates solar energy, IoT, and communication technologies to enhance energy efficiency and thermal comfort in buildings. The physical system maximizes energy efficiency by harnessing solar energy and managing, storing, and distributing it based on demand. The control system uses advanced IoT and cloud technologies for real-time monitoring and management. The solution was tested in two real-world settings, showing its effectiveness in providing heating and cooling using only solar energy. The system's integration of IoT and communication technologies enhances functionality and contributes to energy optimization. The results from the two test installations demonstrate the system's ability to reduce energy costs and emissions, with significant reductions in energy consumption and CO2 emissions after the retrofit. The system's implementation in real-world residential settings highlights its potential for widespread adoption as a key component in the global effort to mitigate the environmental impact of the building sector.The article presents an integrated energy management solution for solar-powered smart buildings, combining a physical system with advanced IoT and cloud-based control systems. The physical system includes a heat pump, photovoltaics, solar thermal panels, and an innovative low-enthalpy radiant wall and ceiling, providing self-sufficient heating and cooling. The control system uses Modbus, HTTP, and MQTT protocols for seamless interconnectivity, monitoring, and remote management. The solution was successfully implemented in a model house in Paris and a deep energy retrofit of a single-family house in Oviedo, Spain, demonstrating increased energy efficiency, improved thermal comfort, and reduced environmental impact. The system integrates solar energy, IoT, and communication technologies to enhance energy efficiency and thermal comfort in buildings. The physical system maximizes energy efficiency by harnessing solar energy and managing, storing, and distributing it based on demand. The control system uses advanced IoT and cloud technologies for real-time monitoring and management. The solution was tested in two real-world settings, showing its effectiveness in providing heating and cooling using only solar energy. The system's integration of IoT and communication technologies enhances functionality and contributes to energy optimization. The results from the two test installations demonstrate the system's ability to reduce energy costs and emissions, with significant reductions in energy consumption and CO2 emissions after the retrofit. The system's implementation in real-world residential settings highlights its potential for widespread adoption as a key component in the global effort to mitigate the environmental impact of the building sector.