Cozy Heat SW Thru-Wall Sauna StoveWood Burning Sauna Stove, Up to 18kW With its convenient through the wall design, which lets you feed the firebox from outside your sauna, the Cozy SW TW sets the standard for wood burning sauna stoves. Hand crafted in Estonia, where sauna is a tradition. Wood fired sauna stoves produce a mild and long lasting heat, and are designed for ladling water over hot stones to create a satisfying steam sauna. 12kW for saunas from 210 to 423 cu. ft. 18kW for