A sauna needs vents in order to provide a flow of fresh air for the user. The proper venting requires vents low and near the heater, and then additional vents high opposite the sauna heater. Since heat rises, the hot air escapes through the top vents while being replaced with fresh air from below. The heater is more than capable of keeping the temperature high in the room while the air is being gradually replaced.
An Almost Heaven Barrel Sauna kit has built-in grills to cover the low vent holes, preventing critters and insects from getting into the cedar sauna. The high vents have an adjustable lever which controls the flow of air, and can be closed to protect the room from critter invasion when not in use.
The Barrel Sauna by Almost Heaven Saunasis very efficient at circulating air within the sauna due to the round shape. There is no wasted air space and the circular design of our cedar sauna allows the air to circulate much better than in a square sauna.