An air heater (1) has a heating air fan (4) in a housing (2) for moving heating air from a front air inlet (25) through a heat exchanger (5) to a heating air outlet (26) at the opposite end face. The object of the invention is to create an air heater (1) which is always capable of sucking in a sufficient quantity of heating air without additional parts and independently of its mounting position. For that purpose, the housing (2) has further air inlets (15) on at least one side around its outer circumference, next to the front air inlet (25).
