Hot water energy consumption is one of the biggest energy consumption and living expense in our life. In this paper, we report the energy consumption of hybrid system by using pellet boiler with CO₂HP in the welfare facility. The facility has multi purpose, such as a dormitory, a hospital and a sheltered workshop for physical disabilities. It needs much hot water for cooking and bathing. We conducted the measurement of the energy consumption for hot water. The results shows that the power of pellet boiler was much less than design value and the COP of CO₂HP was very low. Therefore, we optimized the usage of thermal storage tank and HP system. Also, we conducted the numerical simulation for hot water supply with the Hybrid system. The result indicate that cost is lower when the difference between water level in a day and that in a night is bigger.