Disclosed herein is an air conditioner and a control method thereof. The air conditioner includes: a housing including a base, a first heat exchanger disposed inside the housing and configured to exchange heat with outdoor air, a second heat exchanger disposed inside the housing and configured to exchange heat with indoor air, a compressor configured to compress a refrigerant for a heat exchange operation performed by the first heat exchanger and the second heat exchanger, a first fan disposed inside the housing and configured to move air along a flow path passing through the first heat exchanger, a drainage device configured to move condensed water condensed on the second heat exchanger inside the housing and collected in the base to the first heat exchanger, and a controller including at least one processor, comprising processing circuitry, individually and/or collectively, configured to, based on the stop of the operation of the compressor, control the drainage device to move the condensed water collected in the base to the first heat exchanger during a drainage time determined based on an operation time of the compressor, and to control the first fan to move air during the drainage time.