An air heater for heating air entering a combustion chamber of an internal combustion engine is disclosed. The air heater includes a heating element having a substantially planar portion and a flange portion. The flange portion is positioned at an angle to the planar portion. The planar portion is positioned within an air flow at an upstream location relative to the flange portion. A structure is operable to position the heating element in communication with the air entering the combustion chamber of the engine. In addition, a thermal expansion joint for interconnecting a heating element and a frame is disclosed.