A heat pump system can be used with a vehicle. A cooling system includes a radiator connected to a cooling line and a first water pump and circulating a coolant along the cooling line so as to cool an electric component. A battery module is provided on a battery cooling line selectively connected to the cooling line through a first valve. And HVAC module includes an internal heater connected to the cooling line through a first connection line, a cooler connected to the battery cooling line through a second connection line, and an opening or closing door provided between the internal heater and the cooler and controlling external air passing through the cooler to be selectively introduced into the internal heater depending on cooling, heating, and heating and dehumidifying modes of the vehicle. A centralized energy is connected to each of the battery cooling line and the cooling line.