To provide a heat pump water heater that provides increased security at midnight by making it difficult to estimate whether anyone is at home from the outside even while no one is at home.
The heat pump water heater comprises a refrigerant circulation circuit 15 including a compressor, a heat radiator, a pressure reducing means and a heat sink; a hot water storage tank 17 for storing hot water heated through a heat exchange with refrigerant at the heat radiator; and a stacked pump 18 for taking water out of the bottom of the hot water storage tank and returning the water to the head of the hot water storage tank after the water is heated by the heat radiator. The refrigerant circulation circuit operates in a predetermined time zone and the hot water heated is stored in the hot water storage tank. The heat pump water heater has a security control means 28 that makes the heat pump water heater look as if operating when it is not operating in the predetermined time zone during which the user is not at home, thereby making it look as if the user is at home.
YOSHIMURA YASUO
WATANABE TAKEJI
Hiroki Naito
Daisuke Nagano