Published on September 17, 2025

The secret to a truly exceptional sauna experience is not just the heater, the stones, or the bench design—it’s a well-planned ventilation system. Unfortunately, air exchange is one of the most underestimated aspects of sauna construction. Without a proper system, oxygen levels drop, temperatures become uneven, and the overall experience can quickly turn uncomfortable. 

Why Ventilation Matters 

Good ventilation ensures that the air inside the steam room remains oxygen-rich. When ventilation is poorly designed, the air layers—hot at the top and cold at the bottom—creating uncomfortable temperature differences. This is one of the most common mistakes in sauna construction and can lead to fatigue, difficulty breathing, and cold feet even when the air at head height is hot. 

The Components of Sauna Ventilation 

A typical sauna ventilation system is made up of three parts: 

1. Supply air pipe – brings in fresh air. 

2. Exhaust air pipe – removes stale air. 

3. Drying pipe – used after a session to remove excess moisture. 

The design depends largely on the type of stove you have, whether it’s electric or wood-fired, and the construction style of that stove. 

Ventilation by Stove Type 

• Closed-sided stoves: Air flows from the bottom to the top, with stones sitting on top of the stove. The supply air pipe should never be directed into the middle of a closed-sided stove, as there’s no airflow there. Instead, the fresh air must be introduced underneath or just above the stove, allowing it to heat up and create circulation. 

• Net-stoves: These have open sides with stones encased in a mesh frame. The supply air pipe should be aimed at the center of the stove (no lower than 40 cm from the floor) where it will be heated and drawn upward. 

If you’re using a wood-fired stove, the placement of the supply air pipe also depends on the hearth door location. It should always be on the opposite side of the hearth door (at the back of the stove) so fresh air isn’t lost directly through the door. 

Electrical vs. Wood-Fired Stove Ventilation 

Ventilation strategies vary significantly depending on the type of heater you choose: 

• Electric stoves: These rely solely on the ventilation system to bring in fresh air and remove stale air. Mechanical ventilation is often recommended because it ensures consistent airflow without depending on natural drafts. For closed-sided electric stoves, the supply air pipe should be positioned directly above the stove, so that the incoming cooler air can fall onto the heater, warm up quickly, and circulate effectively. For net-style electric stoves, where the stones are surrounded by an open mesh, the supply air pipe can be placed either to the side at the middle height of the stove or directly above the stove. Both locations allow fresh air to reach the center of the stove and heat evenly, creating optimal air circulation. Exhaust vents are usually positioned low on the opposite wall (but at least 20cm above the intake with gravity-based ventilation) to draw cooler air out and maintain steady circulation. 

• Wood-fired stoves: These create natural airflow because the combustion process draws in oxygen. If the stove’s hearth door is inside the steam room, the stove itself acts as an exhaust, and a separate exhaust pipe may not be necessary. If the hearth door is outside the steam room, an exhaust air pipe on the opposite wall becomes essential. In addition, wood-burning stoves require extra oxygen for combustion, so the supply air pipe must be placed carefully—ideally on the opposite side of the hearth door (meaning the back side of the stove, not necessarily the opposite wall). 

For closed-sided wood-fired stoves, the fresh air intake should be directed underneath or directly above the stove so that the cooler air can be properly heated and circulated. Avoid placing the intake in the middle of the stove where air cannot flow. For net-style wood-fired stoves, the intake pipe can be placed at the middle height of the stove or directly above it, ensuring the fresh air reaches the center of the stone mass for optimal circulation. 

Mechanical ventilation can be used with wood-fired stoves, but it must be designed very carefully. Because these stoves rely on a steady supply of oxygen for combustion, any imbalance in air pressure can cause the stove to draw exhaust gases back into the room. If a fan-driven exhaust system creates negative pressure (where more air is being pulled out than supplied in), it can disrupt combustion and lead to incomplete burning of wood. This can generate dangerously high levels of carbon monoxide (CO), which is odorless and potentially deadly. 

When using mechanical ventilation with a wood-fired stove, it is essential to: 

• Ensure the supply air pipe is large enough to deliver as much (or more) air as the exhaust is pulling out. 

• Use a ventilation system that balances intake and exhaust to maintain neutral or slightly positive pressure in the room. 

• Have the system designed and installed by a professional who understands sauna airflow and the stove manufacturer’s guidelines. 

Mechanical vs. Gravity-Based Ventilation 

• Mechanical ventilation: Suitable for both electric and wood stoves (when the hearth door is outside the steam room). Fresh air is actively pulled in and stale air is pushed out (make sure that the exhaust ventilation is placed low to prevent cold feet). However, mechanical systems with wood-fired stoves need careful planning to avoid low pressure and dangerous carbon monoxide buildup. 

• Gravity-based ventilation: Relies on natural airflow. For closed-sided stoves, the supply air should be near the floor or just above the stove (no lower than 80 cm from the floor). For net-stoves, the pipe should be closer to the middle of the stove. The exhaust air pipe should always be on the opposite wall and 20cm above the intake vent. 

The Role of the Drying Pipe 

The drying pipe is essential for airing out the sauna after use. During a session, it should remain closed, as leaving it open can cause heat stratification and cold feet. 
 
An alternative solution—especially in saunas without a dedicated drying pipe—is to simply leave the steam room door open after use. This allows fresh air to circulate naturally, helping to dry out the space effectively. It’s a simple yet practical method that works well in home saunas or smaller setups. 

Plan Carefully or Consult a Professional 

A poorly ventilated sauna can be exhausting rather than invigorating. The right ventilation system depends on your stove type, stove construction, and even how the stove is loaded. If you’re unsure, consult a professional to design a solution that delivers steady fresh air, consistent temperatures, and the perfect sauna environment.