This paper describes a building prototype experimental set-up used for testing active and passive systems for energy savings, presenting the used methodology, reviewing the main experimental results and identifying limitations. The test facility is located in Puigverd de Lleida (Spain) and has been experimentally evaluating different materials, technologies and systems which might be integrated in building design to provide energy savings for space heating and cooling since 2002. The research fields of passive technologies covered the effect of using different insulating materials, construction systems based on sustainable materials, addition of phase change materials in building envelopes and green infrastructures such as green roofs and walls. On the other hand, the active systems tested were focused in exploiting different available renewable energy source available, such a solar thermal, free-cooling with night air, or geothermal heat, using thermal energy storage systems to shift the heating and cooling loads.