The project consists on the refurbishment of an old traditional Catalan home from the modernism movement; build on 1932 in l’Ametlla del Vallès, Barcelona. The challenge was to obtain a low energy-consuming home, and to achieve it we opted to build a box with wood frame structure inside the existing façades, demolishing interior partitions and the existing flat roof. A two-levelled pinewood roof was created in order to open wide windows to the south, which contributed to guarantee a good use of the sun’s energy. The interior is an open space, organized by a central core with a total of 83,6 m