This project aims to contribute to environmental sustainability through the use of conversational assistants and monitoring of energy consumption at home. Thus, the motivation of the project leads to encourage the responsible energy consumption in the user through the interaction with these conversational assistants. To do this, in the system developed, we will make use of such devices and several wireless smart plugs with built-in Wi-Fi capabilities. The development of the project has followed the agile Scrum methodology, with the division of the proyect into sprints. This system, called GreenMoCa, consists of several software components which have allowed voice commands to be processed and, based on this processing, it has been possible to provide the capacity to act on the devices, as well as to obtain information about the energy consumption data, monitored by the plug, providing the user with essential feedback for sustainable energy consumption. Likewise, by means of a usability evaluation, it has been possible to check and analyse both the user experience and the behaviour of the system. The results include a positive assessment of the participants and, above all, the natural interaction they have shown with the GreenMoCa system.