Fluid heating system

A heating system (203) is provided with: a heat pump unit (220) that operates by means of electric power; a flow circuit (203a); a boiler unit (210) that has a burner (211) and heats water; and a heating control unit. The heat pump unit (220) has a heat pump circuit (221) in which a refrigerant circulates. The flow circuit (203a) allows water heated by the refrigerant to flow. The heating control unit has an operation control unit and an upper limit value acquisition unit that acquires the upper limit value of the power consumption of the heat pump unit (220). The operation control unit controls the operation of the heat pump unit (220) such that the power consumption does not exceed the upper limit value during a first time period in which the upper limit value needs to be complied. The operation control unit operates the boiler unit (210) when the amount of heat is insufficient when water is heated only by the heat pump unit (220) during a first period of time. 制热系统(203)具备：热泵单元(220)，其借助电力进行运转；流动回路(203a)；锅炉单