An indoor apparatus in an air-conditioning system, wherein the indoor apparatus includes: a heat-exchanger for exchanging heat between refrigerant and indoor air; a fan rotating to provide air to flow to the heat-exchanger; and an expansion valve for expanding refrigerant discharged from the heat-exchanger, the indoor apparatus being characterized in that the indoor apparatus further includes: a first temperature sensor disposed on a first conduit for supplying refrigerant to the heat-exchanger, wherein the first temperature sensor detects a first temperature of refrigerant to be fed into the heat-exchanger; a second temperature sensor disposed on a second conduit for receiving refrigerant from the heat-exchanger, wherein the second temperature sensor detects a second temperature of refrigerant discharged from the heat-exchanger; and a controller configured to: calculate a superheat based on a difference between the first and second temperatures; characterised in that the controller is further configured to control activation or deactivation of the fan and/or opening or closing of the expansion valve based on the calculated superheat to reduce a noise level of the indoor apparatus, wherein the indoor apparatus further includes a noise sensor for measuring a noise level of the indoor apparatus, wherein the controller is further configured to control activation or deactivation of the fan and/or opening or closing of the expansion valve based on the noise level measured by the noise sensor to reduce the noise level of the indoor apparatus. a heat-exchanger for exchanging heat between refrigerant and indoor air; a fan rotating to provide air to flow to the heat-exchanger; and an expansion valve for expanding refrigerant discharged from the heat-exchanger, the indoor apparatus being characterized in that the indoor apparatus further includes: a first temperature sensor disposed on a first conduit for supplying refrigerant to the heat-exchanger, wherein the first temperature sensor detects a first temperature of refrigerant to be fed into the heat-exchanger; a second temperature sensor disposed on a second conduit for receiving refrigerant from the heat-exchanger, wherein the second temperature sensor detects a second temperature of refrigerant discharged from the heat-exchanger; and a controller configured to: calculate a superheat based on a difference between the first and second temperatures; characterised in that the controller is further configured to control activation or deactivation of the fan and/or opening or closing of the expansion valve based on the calculated superheat to reduce a noise level of the indoor apparatus, wherein the indoor apparatus further includes a noise sensor for measuring a noise level of the indoor apparatus, wherein the controller is further configured to control activation or deactivation of the fan and/or opening or closing of the expansion valve based on the noise level measured by the noise sensor to reduce the noise level of the indoor apparatus. a first temperature sensor disposed on a first conduit for supplying refrigerant to the heat-exchanger, wherein the first temperature sensor detects a first temperature of refrigerant to be fed into the heat-exchanger; a second temperature sensor disposed on a second conduit for receiving refrigerant from the heat-exchanger, wherein the second temperature sensor detects a second temperature of refrigerant discharged from the heat-exchanger; and a controller configured to: calculate a superheat based on a difference between the first and second temperatures; characterised in that the controller is further configured to control activation or deactivation of the fan and/or opening or closing of the expansion valve based on the calculated superheat to reduce a noise level of the indoor apparatus, wherein the indoor apparatus further includes a noise sensor for measuring a noise level of the indoor apparatus, wherein the controller is further configured to control activation or deactivation of the fan and/or opening or closing of the expansion valve based on the noise level measured by the noise sensor to reduce the noise level of the indoor apparatus. calculate a superheat based on a difference between the first and second temperatures; characterised in that the controller is further configured to control activation or deactivation of the fan and/or opening or closing of the expansion valve based on the calculated superheat to reduce a noise level of the indoor apparatus, wherein the indoor apparatus further includes a noise sensor for measuring a noise level of the indoor apparatus, wherein the controller is further configured to control activation or deactivation of the fan and/or opening or closing of the expansion valve based on the noise level measured by the noise sensor to reduce the noise level of the indoor apparatus.