Electric tubular heating element set for subsequent installation in the air/water heat pump LIK 12TU with increased electric heating and hot water preparation in mono-energetic system operation. Consists of a tubular heating element (can be reconnected to 2/4/6 kW), contactor, safety temperature limiter, pre-assembled cable sets including plugs, through terminals, labeling plates and assembly material. Connection for built-in heating element G 1'AG, max. volume flow 2.0 m/h, control range 30 - 80 °C..