Electrical appliance producing hot water, comprising: a refrigerating circuit comprising: a hot water tank; a cold water buffer tank; an evaporator to evaporate a cooling fluid; a condenser to condense a cooling fluid; a refrigerating compressor with a refrigerator inlet connected to an evaporator outlet and a refrigerator outlet connected to a condenser inlet; an expansion element with an expansion inlet connected to a condenser outlet and an expansion outlet connected to an evaporator inlet; the electrical appliance producing hot water comprising: a tap water inlet to supply tap water to the electrical appliance; a first pipe from the tap water inlet to an inlet of the hot water tank to supply tap water to the hot water tank; a second pipe from the tap water inlet to an inlet of the cold water tank to supply tap water to the cold water buffer tank; where: the cold water buffer tank: houses the evaporator configured to cool down the water contained in the cold water buffer tank when the cooling fluid in the evaporator absorbs the heat of the water contained in the cold water buffer tank, generating cold water for consumption; has a first consumption cold water outlet; the hot water tank: has a consumption hot water outlet; houses the condenser configured to heat the water contained in the hot water tank when the heating fluid in the condenser transfers the condensation heat to the water contained in the hot water tank, generating hot water for consumption; said electrical appliance producing hot water characterized in that the cold water buffer tank has a second surplus water outlet for drainage; and in that said electrical appliance producing hot water comprises a third pipe from the tap water inlet to a water-to-water exchanger inlet which has a cooled water outlet for consumption; a waste grey water inlet to supply water to the cold water buffer tank. a refrigerating circuit comprising: a hot water tank; a cold water buffer tank; an evaporator to evaporate a cooling fluid; a condenser to condense a cooling fluid; a refrigerating compressor with a refrigerator inlet connected to an evaporator outlet and a refrigerator outlet connected to a condenser inlet; an expansion element with an expansion inlet connected to a condenser outlet and an expansion outlet connected to an evaporator inlet; a hot water tank; a cold water buffer tank; an evaporator to evaporate a cooling fluid; a condenser to condense a cooling fluid; a refrigerating compressor with a refrigerator inlet connected to an evaporator outlet and a refrigerator outlet connected to a condenser inlet; an expansion element with an expansion inlet connected to a condenser outlet and an expansion outlet connected to an evaporator inlet; a tap water inlet to supply tap water to the electrical appliance; a first pipe from the tap water inlet to an inlet of the hot water tank to supply tap water to the hot water tank; a second pipe from the tap water inlet to an inlet of the cold water tank to supply tap water to the cold water buffer tank; the cold water buffer tank: houses the evaporator configured to cool down the water contained in the cold water buffer tank when the cooling fluid in the evaporator absorbs the heat of the water contained in the cold water buffer tank, generating cold water for consumption; has a first consumption cold water outlet; houses the evaporator configured to cool down the water contained in the cold water buffer tank when the cooling fluid in the evaporator absorbs the heat of the water contained in the cold water buffer tank, generating cold water for consumption; has a first consumption cold water outlet; the hot water tank: has a consumption hot water outlet; houses the condenser configured to heat the water contained in the hot water tank when the heating fluid in the condenser transfers the condensation heat to the water contained in the hot water tank, generating hot water for consumption; has a consumption hot water outlet; houses the condenser configured to heat the water contained in the hot water tank when the heating fluid in the condenser transfers the condensation heat to the water contained in the hot water tank, generating hot water for consumption;