This study aims at providing a basic data for the development of high energy efficient environment system in the cage (poultry buildings) and cold potable water supply to reduce the summer heat stress. For this study, the cage area size was 273m 2 and the air-to-water heat pump capacity was 20RT for heating and cooling. As the result of this study, the temperature of the drinking water supplied by heat pump was maintained at the set temperature of 15℃. However, the water temperature of control was 23~28 ℃ due to the effect of outside temperature. The average internal cage temperature was 25.3 ℃ in the test group and 28.1 ℃ in the control group, which was 2.8 ℃ higher than that of the control group. The relative humidity was 76.2% in the test group and 75.0% in the control group. The broiler drank 23.2 L / day in the test group and 21.5 L / day in the control group. Daily feed intake was 937 g and and 725 g in the cold water and control water respectively. The feed intake of 212 g was higher than that of cold water. The feeding rates were 1.8 and 1.9. Body weights were 1,523 g and 1,164 g in the cold water and control water respectively. The weight gain was 359 g in the test group fed with cold water and 392 g in the control group. When compared with the control group, the mortality rate was reduced by 84% in the cold water feeding test. It is necessary that future research will continue to reduce the incidence of such livestock accidents.’.