The contribute describes the European strategies to support the development of transition pathways for a low carbon energy system in the UE, including program documents as the Energy Roadmap 2050, financing instruments, like Horizon 2020 calls, and European Directives. Energy systems are increasingly driven by the need to meet challenging carbon emission reduction goals for the next 30 years. This implies radical changes to current energy uses to be achieved maintaining secure supplies and reasonable energy service demands at affordable costs. The contribute of building sector to the low-carbon economy is a crucial challenge, and it could open new development opportunities, working on the main drivers of the decarbonization in buildings: energy demand reduction, increased use of renewables and the integration of a decarbonised power sector.