Indonesia is a tropical country that has hot air, dirty (dusty, smoky) and uncertain winds. With such conditions, to provide comfort needed cooling device that is AC (Air Conditioner). AC system has become the need for an office building in order to provide comfort for employees so as to increase productivity and waiters to costumer. AC is an electronics that requires a lot of electrical power. AC capacity of large electric power required will also be greater. Many electric power also resulted in more and more expenses incurred. The need for the right choice of AC capacity (cooling capacity) that can save the use of electric power. The selection of AC capacity is calculated based on the area of the room so that the incorrect use of AC capacity is too large to cause waste or too small to cause less cold. This type of AC system also greatly affects the power consumption factor so that proper AC system is required. In addition, the office building comfort and tidiness of the air conditioning system is necessary to be a neat and beautiful office. Along with the development of special technology AC there is the latest AC system that is AC VRV (Variable Refrigerant Volume) IV. The Admission Building of Muhammadiyah University of Yogyakarta has a VRV IV system that has the ability to prevent excessive cooling by adjusting the volume of refrigerant (refrigerant). In addition, the AC VRV IV system uses one outdoor unit used for more than two indoors so it does not spawn many places for outdoor units. Connection ratio of outdoor floor and basement floor 106,17% and floor 2 equal to 120%. The capacity of outdoor units on each floor is good because the connection ratio is still below 160%. At full load the power consumption of AC VRV IV is 41,103 watt lower than the result of non-inverter power consumption 56,555 watt AC. Thus, AC VRV IV System further saves in power consumption.