Making efficient use of energy in buildings is a paramount challenge to conserve energy and reduce greenhouse effects. GreenerBuildings will investigate how buildings can dynamically adapt their operations according to actual use, aiming at substantial energy savings.People spend a great deal of time in buildings, may these be offices, hospitals or commercial buildings. While active indoor, people desire to have comforting lighting and microclimate conditions that adapt to their activity and wishes. With GreenerBuildings we propose to realise an integrated solution that addresses the challenge of energy-aware adaptation from basic (energy harvesting) sensors and actuators, up to the embedded software for coordinating thousands of smart objects with the goals of energy saving and user support. Our vision is that buildings can respond to their actual use and changes in their environment; interact with their occupants through novel ubiquitous sensing and occupant behaviour inference techniques and that can transparently adapt a building's function and operation. The project embraces the following key principles in order to achieve its goals: living lab experimentation/validation, agile consortium, a spiral development model, and a user centric approach. In particular, the validation will consider test cases with at least 1.000 devices deployed in different living lab buildings.The specific composition of the Consortium, consisting of top-class universities and research centres (TUE, RUG, CINI, UOR, ITRI), of leader industrial partners specialized in building automation and lighting (PRE) and of SMEs specialised in energy harvesting sensors and actuators (ENO), and of thermodynamics applications  (FSA), guarantees a widespread dissemination and exploitation of the project results, based on well funded scientific and technological innovation.