A circulating fluidized bed furnace (10) comprising an outer furnace wall (10r), surrounding an inner combustion space (10c) of a circulating fluidized bed type, and a heat exchange chamber (20), which is friction-locked to said outer furnace wall, wherein said heat exchange chamber is further supported by one or more structural elements (50), each of which being provided with two ends, a first end (50f) being fixed to a section of the furnace wall, while a second end (50s) being fixed to the heat exchange chamber at an offset to the furnace wall,