A smoke sauna is a wood-fired sauna without a chimney. When the sauna room is heated, it is filled with smoke, causing the interior surfaces of the room to be dark and stained by smoke. It takes much longer to heat a smoke sauna than a modern sauna, because all the required heat has to be stored in the stones of the stove in a single heating session. The stove also needs to be much larger than those in use today to allow enough heat to be stored in the stones. Before going to the sauna, the smoke is let out of the sauna room and the rooms are ventilated. There are no fumes and no smoke in a well-heated smoke sauna, the air is clean, and the heat is not scorching. The smoke sauna has its own associated customs, passed down from generation to generation.
The stamp depicts the sauna of the Punga farm from the second half of the nineteenth century, located in the Estonian Open Air Museum, originally from the village of Koila in Viru-Nigula parish.