Information and Communication Technologies (ICT) are today pervasive to all industrial and business sectors. They are expected to generate deep impacts on reducing energy use and increasing energy efficiency in buildings. Although versatile statistical information is available on energy saving in different buildings, there is still limited understanding about the potential of ICT to reduce energy use. In order to put ICT at the core of the energy efficiency effort and to enable reaching their full potential, it is necessary to foster research and development (R&D) into novel ICT-based solutions and strengthen their take-up — so that the energy consumption of buildings can be further reduced by adding intelligence to components, equipments, processes and services. In this paper, ICT based support tools to energy efficiency in buildings are investigated. The state-of-the-art in ICT for buildings is discussed with focuses on the role of ICT and their priorities for energy efficiency. Several key areas have been identified where there is potential to improve energy efficiency through the use of ICT. As an energy efficient housing example, the Lighthouse built in the United Kingdom is discussed with its ICT integrated building services and demonstration data of energy use. The paper concludes that in order to achieve the energy efficiency in buildings, further support of multidisciplinary R&D and innovation demonstrating the potential of ICT based solutions are needed to foster and accelerate the deployment of energy efficient solutions in buildings.