A heater behind the benches. Harvia Hidden Heater is a practical heater requiring very little space. It is mounted behind the benches and is therefore very well-suited for community saunas. Optional accessories for Hidden Heater include a soapstone bowl and a flexible hose pipe. The heat remains comfortably even when water is conveyed to the heater little by little. The bowl is placed on the bench and water is poured into it. The hose pipe takes the water to the heater. This heater is designed for heavy-duty use and completely made of high-quality stainless steel. The Hidden Heater is controlled by a separate control unit. Hidden Heater models HH6, HH9 and HH12.