A fan for a gas burner system where at the outflow side of the fan a combustion gas is fed in, in order to form a flammable mixture of gas and air, the fan comprising a spiral-shaped fan housing having a rotational axis and an air outlet; the air outlet of the fan housing widening like a snail shell towards the outflow side of the fan; an impeller that is arranged concentric to the rotational axis in the interior of the fan housing; and an electric motor for driving the impeller, which is integrated at the center of the impeller.