In order to reduce the energy demand of households, a new type of Trombe wall is being designed during a ‘research through design project’ called ‘Double Face 2.0’. A Trombe wall is a passive system that reduces the energy demand of a building. In winter, it captures the heat from the sun during the day and releases this heat into the building at night. In summer, it captures the heat from internal sources during the day and releases that heat at night towards outdoors. First simulations showed that our prototype of a lightweight, translucent, adjustable Trombe wall reduces the energy demand for heating of a typical Dutch household by 25-30%. Instead of stone-like materials, the new type of Trombe wall will consist of translucent materials: phase change material (pcm) and insulating aerogel. The insulation gives the opportunity to direct the thermal mass of the pcm. In this way, the system is adjustable for cooling and heating purposes. A selection of the design concepts is described in this paper, explaining the design choices and method of validation. Depending on the level of detail, different simulation software has been used. This paper describes the comparison and the experiences of using it.@en