This paper presents an integrated energy management solution for solar-powered smart buildings, combining a multifaceted 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 utilizes Modbus, HTTP, and MQTT protocols for seamless interconnectivity, monitoring, and remote management. The solution has been successfully implemented in an average-sized model house in Paris and a deep energy retrofit of a semidetached single-family house in Oviedo, Spain, demonstrating increased energy efficiency, improved thermal comfort, and reduced environmental impact compared to conventional alternatives. The study highlights the potential of integrating solar energy, IoT, and communication technologies into smart buildings, contributing to the global effort to reduce the environmental impact of the building sector.This paper presents an integrated energy management solution for solar-powered smart buildings, combining a multifaceted 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 utilizes Modbus, HTTP, and MQTT protocols for seamless interconnectivity, monitoring, and remote management. The solution has been successfully implemented in an average-sized model house in Paris and a deep energy retrofit of a semidetached single-family house in Oviedo, Spain, demonstrating increased energy efficiency, improved thermal comfort, and reduced environmental impact compared to conventional alternatives. The study highlights the potential of integrating solar energy, IoT, and communication technologies into smart buildings, contributing to the global effort to reduce the environmental impact of the building sector.