A portable radiant heater supplied by an associated fuel source comprises a housing having a handle for transporting the heater. A plenum in the housing receives fuel from the associated fuel source and mixes the fuel with air. A burner assembly includes a radiant surface that communicates with the plenum. A regulator limits the pressure of the associated propane source to approximately eleven inches water column, and an oxygen depletion system associated with the burner assembly automatically shuts off the heater at a predetermined oxygen content. A tank fitting with a position that can be adjusted relative to the regulator facilitates the installation of the associated fuel source to the heater.