Abstract: A portable heater comprising a fire chamber vessel, an outer enclosure container around the vessel for retaining it, the container bottom being spaced below the vessel bottom to define a vertical space therebetween, the container breadth being sufficiently greater than the vessel breadth to cause the container peripheral wall and the vessel peripheral wall to define a circumferential space therebetween, an upright air flow control member in the circumferential space spaced from the container peripheral wall to create convection air-flow, heat-insulating space between the control member and container peripheral wall, and having an upper discharge outlet; the control member being spaced from the vessel peripheral wall and oriented to create an upwardly convergent convection heat exchange air flow conduit between the flow control member and the vessel peripheral wall, and an upper heat outlet between said control member and said vessel for discharge of heated air; air flow inlet openings in the container adjacen