Sauna Ventilation is Mission Critical

Anytime a client asks me what the most important consideration is when building a sauna I always answer with the same variable -- ventilation. This a very painful variable to neglect, as correcting it after the original installation typically requires intrusively pulling apart of your sauna walls in order to properly install what's needed.

A properly ventilated sauna will:

• Provide adequate oxygen for sauna user (huge deleterious effects if absent)

• Evenly heat the sauna space, reducing temperature gradient / stratification

• Improve steam (Löyly) quality -- it should feel gentle and deep

• Manage moisture levels and dry-time in between sessions

• Reduce odors and improve air freshness (no gym locker aroma!)

An improperly ventilated sauna will:

• Create suffocating, heavy air that's oxygen depleted

• Facilitates extreme heat stratification between levels of the sauna

• Harsh / painful steam (Löyly) due to immediate condensation once it hits lower levels of the sauna

• Deteriorate the building components faster by keeping moisture trapped, leading to mold, rot and structural damage long-term

• Works the heating unit extra with excess humidity and heat stagnation, reducing its usable lifespan

Diagram of sauna ventilation from Finlandia. This is nearly exactly how my personal sauna's ventilation is setup.

In a future blog post, I will break down the two main approaches to sauna ventilation and when its a good application for one or the other. I will also cover a few of my favorite methods of installing ventilation in typical applications, such as indoor basement saunas and exterior sauna builds.

Spoiler alert: the simpler the system the better.