Abstract-One of the biggest societal challenges is to reduce the impact on the environment [1]. During the last years a lot of digital tools and green apps have been developed in order to help individuals to lower their ecological footprint. These green applications can make use of the specific functionalities of smartphones such as mobility, smartness and connectedness in order to provide better and more personalized services [2-3]. However these applications mostly focus on one aspect of sustainability, such as transportation or electricity consumption. Moreover user research concerning the users' needs and wants towards these applications is lacking or is limited to only one research step such as testing a prototype version [3]. One approach in which end-users are involved intensively is the Living Lab approach. Therefore within this paper we will explore the role of Living Labs as an innovation intermediary in the research into green apps and more specific on the needs and wants of end-users concerning green apps. Therefore we conducted a single case study research of a Living Lab project in which the ecological footprint of end-users is being measured based on their transportation, housing as well as consumption. We argue that the Living Lab approach adds added value for conducting research on green apps because the user plays a central role within this research which makes it possible to adapt the service to the needs and wants of end-users through an iterative approach. Which is important seen the need of personalized green apps. Next to this the role of Living Labs as intermediary also assisted into the development of the green app.