AIR CONDITIONER

PROBLEM TO BE SOLVED: To provide an air conditioner capable of keeping its heating performance even under a very low temperature condition and performing defrosting treatment without giving uncomfortable feeling in stopping an operation. SOLUTION: In this air conditioner provided with a bypass circuit having a refrigerant heater 8 in a heat pump type refrigerating cycle constituted by connecting at least a compressor 1, a four-way valve 2, an indoor heat exchanger 3, a pressure reducer 4 and an outdoor heat exchangers 5 by a refrigerant circuit, and stopped after defrosting the outdoor heat exchanger 5 without switching the four-way valve 2, by allowing the refrigerant superheated by the refrigerant heater 8 to flow to the outdoor heat exchanger 5 in termination of a heating operation, operational frequencies of the compressor 1 are independently determined between normal defrosting and defrosting in stopping, thus the outdoor heat exchanger 5 can be sufficiently defrosted without giving the uncomfortable feeling/discomfort caused by refrigerant noise and switching sound of the four-way valve 2 to the user, and without making the user to sense cold air feeling in accompany with the lowering of an indoor temperature. COPYRIGHT: (C)2008,JPO&INPIT