A system for air-conditioning and hot-water supply configured to selectively perform a cooling operation and heating operation, comprising: an outdoor unit having a compressor, an outdoor heat exchanger, and a switching valve; a plurality of indoor units (120a, 120b) each of which is connected to the outdoor unit and includes an indoor heat exchanger (121a, 121b); a hot-water supply unit connected to the outdoor unit so as to be arranged in parallel to the plurality of indoor units (120a, 120b) and including a refrigerant-water heat exchanger, the hot-water supply unit having a hot water tank for storing hot water; a controller configured to monitor an occurrence of a request from any one of the plurality of indoor units (120a, 120b); and a hot-water supply controller configured to monitor the temperature of the hot water stored in the hot water tank, determine that the current water temperature is below a target temperature set by a user or below a threshold temperature calculated from the target temperature, and send a hot-water request; wherein the outdoor unit, the indoor units (120a, 120b), and the hot-water supply unit are connected by a gas main pipe and a liquid main pipe; during the heating operation, the outdoor unit forms a refrigerant circuit for heating in which the outdoor heating exchanger, the switching valve, the compressor, and the switching valve are sequentially connected in this order from the liquid main pipe side toward the gas main pipe; during the cooling operation, the outdoor unit forms a refrigerant circuit for cooling in which the switching valve, the compressor, the switching valve, and the outdoor heating exchanger are sequentially connected in this order from the gas main pipe side toward the liquid main pipe; and the hot-water supply unit has a function of transferring heating energy or cooling energy from the outdoor unit to water so as to perform the heating operation or the cooling operation thereon; characterised in that the controller is further configured to monitor an occurrence of the hot-water supply request from the hot-water supply controller during the cooling operation performed at at least one of the plurality of indoor units (120a, 120b), and then to start the heating operation in accordance with the hot-water request; and the controller is further configured to resume said cooling operation where said request is an increase request for an increase of load of said cooling operation. an outdoor unit having a compressor, an outdoor heat exchanger, and a switching valve; a plurality of indoor units (120a, 120b) each of which is connected to the outdoor unit and includes an indoor heat exchanger (121a, 121b); a hot-water supply unit connected to the outdoor unit so as to be arranged in parallel to the plurality of indoor units (120a, 120b) and including a refrigerant-water heat exchanger, the hot-water supply unit having a hot water tank for storing hot water; a controller configured to monitor an occurrence of a request from any one of the plurality of indoor units (120a, 120b); and a hot-water supply controller configured to monitor the temperature of the hot water stored in the hot water tank, determine that the current water temperature is below a target temperature set by a user or below a threshold temperature calculated from the target temperature, and send a hot-water request; wherein the outdoor unit, the indoor units (120a, 120b), and the hot-water supply unit are connected by a gas main pipe and a liquid main pipe; during the heating operation, the outdoor unit forms a refrigerant circuit for heating in which the outdoor heating exchanger, the switching valve, the compressor, and the switching valve are sequentially connected in this order from the liquid main pipe side toward the gas main pipe; during the cooling operation, the outdoor unit forms a refrigerant circuit for cooling in which the switching valve, the compressor, the switching valve, and the outdoor heating exchanger are sequentially connected in this order from the gas main pipe side toward the liquid main pipe; and the hot-water supply unit has a function of transferring heating energy or cooling energy from the outdoor unit to water so as to perform the heating operation or the cooling operation thereon; characterised in that the controller is further configured to monitor an occurrence of the hot-water supply request from the hot-water supply controller during the cooling operation performed at at least one of the plurality of indoor units (120a, 120b), and then to start the heating operation in accordance with the hot-water request; and the controller is further configured to resume said cooling operation where said request is an increase request for an increase of load of said cooling operation.