Sauna Ventilation: What Are the Most Important Considerations?

The secret to a good sauna is a well-planned ventilation solution. Unfortunately, the significance of the air exchange system and its planning are often underestimated in a sauna building. Having oxygen-rich air in the sauna is yet just as important as the capacity of the sauna heater, the quantity of sauna stones or the width and height of the sauna bench. Improper air circulation of the steam room results in a lack of air and discomfort. Air of the room stratifies if the ventilation system is not constructed properly, and the temperature at the lower stages of the sauna bench drops.

Layered air due to badly planned ventilation is one of the most typical mistakes in sauna construction.

The type and construction of the ventilation system depends on which kind of stove you have. So, make sure you think about ventilation when choosing a stove for your sauna.

A typical ventilation system is made up of three parts (sometimes two):

• supply air pipe
• exhaust air pipe
• drying pipe

Your ventilation solution depends on whether the room has gravity-based ventilation or mechanical ventilation. In general, the supply air pipe should be positioned close to the stove at the proper height, so that the incoming colder air reaches the heat of the stove, heats up, and creates circulation in the room.

Choice of ventilation system depends on the stove type

Air circulation in the steam room must correspond to the particular stove. Electric stoves require a different ventilation solution than stoves that use wood. You must also consider whether the stove door (stove hearth) is inside the steam room or the stove is filled from outside the steam room.

The construction of the stove also plays a role. When planning your ventilation, it is important to know the difference between closed-sided stoves and open or net-stoves.

 

In case of closed-sided stoves

• the air circulates from bottom to top and the stones are placed on top of the stove. A very common mistake is placing the supply air pipe in the middle of the closed-sided stove where there is no air access. In this case, the incoming air is not heated properly and sufficient air circulation will not occur. And it does not matter whether your closed-sided stove is electric or wood-heated. The incoming air should be directed underneath the stove or above the stove, according to the particularities of the sauna and the stove. See below for concrete cases

 

In case of a net-stove

• the sides are open and the stones are situated inside a massive net with plenty of air access from all sides, the supply air pipe should be placed in the middle of the stove. This directs air to the centre of the stove where it will be heated and lifted to create air circulation in the room.

 

Drying

All saunas must have a drying pipe. As its name suggests, this pipe is used for drying the sauna after use. This can be opened if the sauna has too much moisture or lacks sufficient oxygen. If possible, though, the drying pipe should be left for drying the sauna, not for fixing other problems. The drying pipe should be closed during the sauna session because the heat in the room may get layered and leave your feet cold. The drying pipe should be located away from the heat source, in the ceiling or high on the wall.

 

Mechanical ventilation

Mechanical ventilation systems are alike for electric stoves and stoves that are heated from the antechamber (i.e. no hearth door in the steam room). Wood-fired stoves fed from the steam room however require special attention.