Air conditioner having sensor and control method thereof

An air conditioner comprising:

• a detection sensor configured to generate a sensor detection value related to an object in a target space;
• an air-conditioning module including a compressor configured to perform an air-conditioning operation;
• memory storing at least one instruction;
• and
• at least one processor, comprising processing circuitry, individually and/or collectively configured to
• execute the at least one instruction to cause the air conditioner to:
• set a first mode of activating the detection sensor or a second mode of deactivating the detection sensor based on an input,
• based on determining that no person is present in the target space for a first reference time based on a sensor detection value from the detection sensor while performing the air-conditioning operation in an activated state of the detection sensor in the first mode, stop the air-conditioning operation of the air-conditioning module,
• based on a second reference time elapsing from a start time of the air-conditioning operation while performing the air-conditioning operation in a deactivated state of the detection sensor in the second mode, activate the detection sensor, and based on determining that no person is present in the target space, stop the air-conditioning operation,
• wherein the second reference time is longer than the first reference time.