The present research investigates a new evaporative cooling technique, which is placed on the roof of a small building in the climate of Crete - Greece. A pond is filled with water up to 0.10-0.12 m deep while an aluminium layer is kept 0.15 above free water surface, allowing ventilation between water level and the aluminium shield. The temperature of water and indoor air is recorded for a 35 days summer period. The water temperature is analyzed, in regard to climatic conditions. According to the experimental records, the daily minimum temperature of water is practically equal to the corresponding air temperature while maximum daily temperature of water is about 8-13 degrees C lower compared to the corresponding value of air. Furthermore, a heat flow analysis based on pond simulation indicates that the cooling effect occurs mainly due to evaporative losses. The effect of the proposed system to the indoor air temperature reduction is also assessed building simulation. According to the results of both experiments and simulation, the maximum indoor air temperature is reduced by 30%, compared to the corresponding temperature of a building without any roof cooling technique. (C) 2014 Elsevier Ltd. All rights reserved.