Water heating system, in particular for mobile homes

The system (10) has a heat transfer assembly (30) for transmission of heat in a heat transfer medium to water in a water reservoir (32). The assembly includes a heat exchanger pipe provided with a heat coupling region that is in thermal interaction with the heat transfer medium. The heat exchanger pipe includes a flow space area for passage of gaseous heat carrier medium from the heat coupling area to a heat decoupling area, and another flow space area for passage of liquid heat carrier medium from the heat decoupling area to the heat coupling area.