An air-conditioning system comprising: an air-conditioning apparatus including an outdoor unit and an indoor unit having a temperature sensor; a controller configured to communicate with the indoor unit and acquire detection data from the temperature sensor; and a terminal configured to communicate with the controller and acquire the detection data from the controller, characterized in that the temperature sensor is a radiation temperature sensor configured to detect radiation temperature in a space to be air conditioned, the terminal is configured to output information on whether a change of the detection data is larger than a predetermined value, wherein either the terminal is configured to transmit a test run instruction to cause the air-conditioning apparatus to perform a test run, and the controller is configured to transmit to the terminal, when receiving the test run instruction, the detection data acquired in advance from the indoor unit before the test run, and then cause the air-conditioning apparatus to perform the test run, acquire from the indoor unit, when the air-conditioning apparatus performs the test run, the detection data after the test run is performed, and transmit the detection data after the test run and acquired from the indoor unit to the terminal, wherein the terminal is configured to detect a change between the detection data before the test run and the detection data after the test run is performed, and output the change; or wherein the indoor unit includes a test run switch for causing the air-conditioning apparatus to perform a test run, is configured to transmit, when the test run switch is turned on, the detection data acquired before the test run switch is turned on, to the controller, and transmit to the controller, after the test run is started, the detection data acquired after the test run is started, wherein the terminal is configured to detect a change between the detection data acquired before the test run switch is turned on and the detection data acquired after the test run is started, and output the change. an air-conditioning apparatus including an outdoor unit and an indoor unit having a temperature sensor; a controller configured to communicate with the indoor unit and acquire detection data from the temperature sensor; and a terminal configured to communicate with the controller and acquire the detection data from the controller, characterized in that the temperature sensor is a radiation temperature sensor configured to detect radiation temperature in a space to be air conditioned, the terminal is configured to output information on whether a change of the detection data is larger than a predetermined value, wherein either the terminal is configured to transmit a test run instruction to cause the air-conditioning apparatus to perform a test run, and the controller is configured to transmit to the terminal, when receiving the test run instruction, the detection data acquired in advance from the indoor unit before the test run, and then cause the air-conditioning apparatus to perform the test run, acquire from the indoor unit, when the air-conditioning apparatus performs the test run, the detection data after the test run is performed, and transmit the detection data after the test run and acquired from the indoor unit to the terminal, wherein the terminal is configured to detect a change between the detection data before the test run and the detection data after the test run is performed, and output the change; or wherein the indoor unit includes a test run switch for causing the air-conditioning apparatus to perform a test run, is configured to transmit, when the test run switch is turned on, the detection data acquired before the test run switch is turned on, to the controller, and transmit to the controller, after the test run is started, the detection data acquired after the test run is started, wherein the terminal is configured to detect a change between the detection data acquired before the test run switch is turned on and the detection data acquired after the test run is started, and output the change.