Heating system for a vehicle

A heating system for a vehicle has a heating air blower ( 24 ) for generating a heating air stream to be introduced into the interior space of a vehicle, a heater ( 22 ) with a heat exchanger arrangement ( 26 ) for heating the heating air stream being delivered by the heating air blower ( 24 ), a mixing arrangement ( 20 ) for setting an outside air/ambient air ratio of the air to be fed to the heat exchanger arrangement ( 26 ), an outside temperature sensor arrangement ( 60 ) for generating an output linked with an outside temperature, and an actuating device ( 42, 46 ). The actuating device ( 42, 46 ) actuates the mixing arrangement ( 20 ) for setting the outside air/ambient air ratio on the basis of an output of the outside temperature sensor arrangement ( 60 ).