A large percentage of the energy consumption occurs in the building sector, especially for heating and cooling. According to the overall goal to decrease the cooling demand in tropical climate, a radical new approach for sustainable architecture is being realized in the Philippines on Palawan near Puerto Princesa City within the EU switchasia project Zero Carbon Resorts (ZCR). This prototype building combines vernacular building elements and indigenous materials with a contemporary architecture and up to date technologies for zero energy buildings. But for a further distribution the functionality of the concept has to be proven and that thermal comfort in a resort cottage made of local renewable resources in tropical climate can be achieved due to design features and natural ventilation without the use of air conditioning units. Within this work a comprehensive monitoring of the local outdoor climate and the indoor environment was carried out, subdivided in a long time monitoring with special focus on the air temperature and the relative humidity and a short time monitoring using the PMV/PPD method for the evaluation of thermal comfort at selected positions. In a first step the indoor conditions of each room were compared with the local outdoor climate, showing that the correlation is dependent on the design of the building, the position of the rooms and the different implemented passive cooling strategies, while also distinctions between different types of sensors and their varying positions within each room were explored. In the second part the PMV/PPD method, based on the standards of ASHRAE and DIN EN ISO 7730, was adapted for the evaluation of thermal comfort in natural ventilated buildings. In addition, the measured values were then also applied to modified psychrometric charts for the use in tropical climate. The results are showing that, considering the circumstances of this extreme hot and humid climate at the project location, acceptable indoor conditions can be achieved by the implemented design features of this sustainable building.