An air conditioning system comprising: a heat source unit that is configured to heat a fluid; a heat exchanger for being installed in a room, the fluid heated by the heat source unit flowing through the heat exchanger and the heat exchanger for performing heat exchange between the fluid and air in the room; a room temperature sensor that is configured to measure a temperature of the room; a human detection sensor that is configured to detect a human body in the room; and a control apparatus that is configured to, when human body is detected by the human detection sensor, control at least one of an amount of heating of the fluid by the heat source unit and an amount of flow of the fluid into the heat exchanger so that the temperature measured by the room temperature sensor becomes a first temperature set in advance, is configured to evaluate a rate at which a human body was detected by the human detection sensor for a time period, which is within a day of a week and dependent on the type of the day of the week, and includes a storage unit that is configured to store the rate for a plurality of time periods and to store, as a second temperature, a temperature set in advance according to the rate at which a human body was detected by the human detection sensor in the past, for each of the time periods, wherein the second temperature is further set to be lower than the first temperature and to be reduced accordingly as the rate in a corresponding one of the time periods is lower, and, wherein the control apparatus is configured to, when no human body is detected by the human detection sensor, control the at least one of the amount of heating of the fluid by the heat source unit and the amount of flow of the fluid into the heat exchanger so that the temperature measured by the room temperature sensor becomes the second temperature stored in the storage unit and corresponding to a current time period corresponding to one of the time periods. a heat source unit that is configured to heat a fluid; a heat exchanger for being installed in a room, the fluid heated by the heat source unit flowing through the heat exchanger and the heat exchanger for performing heat exchange between the fluid and air in the room; a room temperature sensor that is configured to measure a temperature of the room; a human detection sensor that is configured to detect a human body in the room; and a control apparatus that is configured to, when human body is detected by the human detection sensor, control at least one of an amount of heating of the fluid by the heat source unit and an amount of flow of the fluid into the heat exchanger so that the temperature measured by the room temperature sensor becomes a first temperature set in advance, is configured to evaluate a rate at which a human body was detected by the human detection sensor for a time period, which is within a day of a week and dependent on the type of the day of the week, and includes a storage unit that is configured to store the rate for a plurality of time periods and to store, as a second temperature, a temperature set in advance according to the rate at which a human body was detected by the human detection sensor in the past, for each of the time periods, wherein the second temperature is further set to be lower than the first temperature and to be reduced accordingly as the rate in a corresponding one of the time periods is lower, and, wherein the control apparatus is configured to, when no human body is detected by the human detection sensor, control the at least one of the amount of heating of the fluid by the heat source unit and the amount of flow of the fluid into the heat exchanger so that the temperature measured by the room temperature sensor becomes the second temperature stored in the storage unit and corresponding to a current time period corresponding to one of the time periods.