Abstract: The invention provides a compartmented gas fired heater in a cabinet-type outer stove casing. The outer stove casing has a downwardly positioned covered bottom with adjustable legs at four corners and an upwardly positioned opened top edge. A heat chamber insert having a covered bottom and an opened top is fitted inside the outer stove casing and retained so a corridor exists between all wall surfaces and the two bottoms. The top of the two sections are covered over the corridor area by a framing cover leaving the top of the heat chamber insert open as a hot air outlet. A caged outlet cover fits over the hot air outlet. Cool air is passed into the heat chamber insert through an air inlet casing. When a controlled gas burner is fired in the corridor below the bottom of the heat insert chamber, heat spirals up the corridors, is conducted through the outer stove casing and through the heat chamber insert walls and convected up through the top hot air outlet.