Keeping living spaces cool in the summer heat is becoming increasingly challenging for residents. The current solutions to this problem are unsatisfactory. In most cases, energy-intensive air conditioning units are used, which in turn contribute to the problem of the heat island effect (Jin et al., 2020) in cities due to their waste heat – or windows and sun blinds have to be closed during the day to maintain comfortable indoor temperatures. As a result, rooms are increasingly isolated from the outside climate. Closed windows can lead to CO2 concentrations that are harmful to health (Federal Environment Agency, 2008). As an alternative, this project is researching solutions for existing and new buildings that create a pleasant indoor climate in summer despite open windows and without technical devices. To this end, we are investigating the potential of apartment floor plans, which is receiving too little attention in the current architectural debate. The study focuses on construction methods that regulate the indoor climate in summer with cooling air circulation and at the same time create a pleasant room temperature throughout all seasons. As part of the research project, principles for multi-story apartments are being developed that respond to the climate conditions of the future from the inside out and offer a holistic architectural solution. The consideration of floor plan organization includes flexible room arrangements, different room heights, proportions, and dimensions, flexible and permeable interior walls, shading elements, and situational low-tech solutions that support air circulation and cooling. Shade and air serve as guiding architectural design elements.