AbstractA parametric analysis for an innovative prototype of passive building, located in south Italy and for residential use, has been conducted to evaluate the thermal energy requirements for heating and cooling applications. The investigation was addressed by considering also the aspect of sustainability, by employing natural materials such as dry sand and wood fibre, and the correspondent effects on the energy performances of the envelope. These materials are usually available on site; they increase the building thermal capacity, which represents a crucial aspect for hot climates, and finally could even be reused after building disposal. The construction system based on the completely dry assembling technique makes the exploitation of the mentioned materials possible. The results of the parametric study were obtained by means of the Design Builder dynamic software, by investigating the glazed surfaces, the control of solar radiation and the exploitation of nocturnal free-cooling. A parametric study allowed for optimization of the envelope, by respecting the limit values of 15 kWh/m2 suggested by the standard passivhaus in its extended formulation for warm climates.