Barrel is the ultimate shape for any sauna. For many reasons. There is 23% less space to be heated when compared with similar size room with corners. Also, the cylinder shape allows natural continuing air circulation because the air is pushed back on the round walls. You will enjoy those longer steam cycles while saving on energy costs. For that ultmate sauna experience we recommend Allwood Barrel Sauna. The Sauna kit #220-WHC is the wood fired heater model designed for smaller patios. This sauna is built to last. The sauna barrel and the walls are made from 1-5/8″ thick slow grown Nordic Spruce. With 6’8″ diameter x 67″ inside length this sauna will comfortably seat 4 adults.