Scandia Manufacturing Electric Ultra 26" x 18" x 29" Wall Mounted Stainless Steel 15.0 kW 240V Phase 3 Large Sauna Heater with Built-in ThermostatIndustrys Most Efficient Electric Heater. The Ultra Sauna heater line was developed in 1964 (formerly by Vico Mfg.) with the goal of developing the only line of convection air flow sauna heaters. By achieving greater air flow, the heater can heat the room more rapidly and extend the life of the heater elements. This is accomplished by a unique element chamber design that separates each element. By restricting air space, the lower cold mass of air