An air conditioner includes: a fan configured to discharge air cooled by a refrigerant; and at least one processor configured to receive a user input for setting an airflow volume of air to be discharged and a desired temperature, increase a frequency of the compressor to a first critical frequency and maintain the frequency of the compressor as the first critical frequency in response to determining that a temperature difference between an indoor temperature and a desired temperature exceeds the critical temperature difference while controlling the fan to discharge the air with the set airflow volume, determine whether an unsatisfactory condition has occurred, based on at least one cool air-conditioning sensation measurement item while maintaining the first critical frequency, and increase the frequency of the compressor to a second critical frequency to further decrease a current temperature of the air in response to determining that the unsatisfactory situation has occurred.