The Wall Series 6kW Sauna Heater Package, Built-In Controls, Stainless Steel The Wall 6kW Sauna Heater Package with Built-In Controls by Harvia comes complete with The Wall SWS60 Sauna Heater and Sauna Stones. This compact heater package combines modern design with flexible installation options, providing improved air circulation and steady warmth in sauna rooms from 177 to 294 cubic feet (CF).