How do sauna heaters work?

Gas sauna heaters are not as common as the electric models but the basic function and operation is the same. A gas burner is fed either through a built-in gas line or a LPG or propane gas tank that heats the metal plate, on which the heat-absorbing sauna stones lie. When the stones are heated, the surrounding air is also heated, which then moves to heat the room via convection. Once the stones are hot, water is gently added to them, the water then immediately evaporates, creating steam. The steam is then circulated through the sauna, creating a warm and humid environment.