A sauna needs to breathe, just like we do. Good ventilation keeps the air fresh, prevents the room from feeling stale, extends your time in the sauna, and makes the experience far more enjoyable.
For electric saunas, we place a vent 8–10 inches above the heater stones and place another vent 10 inches off the floor on the opposite wall. Sometimes, the door gap is enough for airflow but we assess all of those details in the design phase of our builds. While this setup isn’t exactly by-the-book (Harvia specs differ), it aligns with our real-world experience from Finland, Europe, and North America. Simply put—it works. We have tested air quality and managed heat and steam loss with thermal cameras and have landed here.
Wood-fired saunas are a different game. Instead of fixed vents, we leave a cavity behind the heater where the stove pipe exits. This naturally draws in fresh air, improving combustion and circulation. Usually, the gap under the door is enough for additional airflow, but we always consider wind, drafts, and avoiding cross breezes. For example a sauna on the edge of a lake with a consistent breeze will function differently than a sauna nestled in the forest.
Fresh air is key. Without it, you’re just sitting in a hot, stuffy box, breathing in CO₂ and getting sleepy. We design our outdoor saunas to maximize oxygen flow without disrupting the Löyly. Every sauna and location is different, but our approach seems to give us and Sip users the most flexibility.
A hot sauna is important. Air quality is even more so.
This doesn't even touch on how we ventilate commercial saunas, which is a whole other story. We apply a formula to the heater size and capacity and regularly test the air during use to establish the appropriate CFM's required to circulate the air. In a commercial setting we also have to consider negative and positive air pressure, as these are typically mechanical systems.
As with everything at Sip, we are always evolving, and we’re always testing what works best. Got questions? Let’s talk.