In this study, commercial air-filled window system, WFW system with domestic water input and WFW system with water tank includes PCM is compared with the comparison of energy consumption in summer climatic conditions. There is a closed water cycle between the WFW and the tank includes PCM. The temperature of the water inside the tank increases over time. This increase causes the temperature rise and phase change of PCM. After this rise, water inside the tank can be used as domestic hot water. There is an open water circulation from the domestic water source to WFW in the second cabinet. The water left window can be used in daily life. Another cabinet has an air-filled commercial window in front. In day time There is a cooling consumption ratios around 0.4 for WFW with domestic water and 0.9 for WFW with PCM tank (without any load or unload of domestic hot water). The consumptions during nighttime of the systems are considered. In summer conditions, the comparison of cabinets can be neglected compared to the daytime consumption.