During 1997, an energy efficient building was designed, featuring energy conservation, passive solar heating, natural cooling and daylighting strategies. It is located in the province of La Pampa, in the temperate semi-arid region of central Argentina. The resulting compact design houses takes 634m2 of useful floor area with main spaces. An audience class, two laboratories, four research offices, one simple class and services make up the building. Solar windows are provided for all main spaces, except in the audience class. Clestories contribute to add solar gains and natural lighting. Summer cooling strategies include: natural ventilation reinforced with aeolian suction pipes in covering. Shading devices in the north elevation protect all windows in summer. Along the design stage, simulation analysis was performed through standard computer models, in order to assess the environmental, energy performance and daylighting of the design alternatives considered. The thermal performance shows an important stability during the simulated stage.