An inlet bleed heater for flowing heated air to the inlet of a compressor is fabricated wholly at a factory site. The heater interconnects a manifold (34) which receives extraction air from the compressor to down tubes (20) in the inlet air duct to supply heated extraction air to the ambient inlet air via piping (50) with bellows (53). The bellows accommodate thermal expansion and contraction of the manifold and the down tubes. The pipe and bellows lie within the height envelope of the bleed heater, facilitating transportation of the heater on its side within overall height and width limitations permitted for road travel.