Sauna ventilation

The common layout

NASS says the most common guidance is an inlet of about 4 x 6 inches near the floor on the heater wall and an outlet on the opposite wall just below the upper bench. NASS says US electric-heater distributors generally want an inlet below the heater and an outlet on the opposite wall just below the upper bench. (North American Sauna Society; North American Sauna Society)

Finnleo puts the intake vent directly under the heater and the exhaust on the opposite wall, ideally about 2 ft above the floor.

Electric heaters

Harvia says the air in a sauna with an electric heater should change six times per hour. For gravity ventilation with an electric heater, Harvia puts the supply vent below or next to the heater, 50 to 100 mm in diameter.

Harvia places the exhaust near the floor as far from the heater as possible, with a pipe twice the supply pipe's diameter. Harvia warns that the supply air must not blow across a heater's separate temperature sensor.

Saunum's US manual puts the intake no higher than 12 inches (30 cm) from the floor, with extraction as far from the heater as possible.

Wood-burning heaters

For a wood-burning heater with gravity ventilation, Harvia puts the fresh-air inlet low near the stove and the outlet high and far from it. Harvia says a wood stove circulates air well by itself, so the outlet mainly removes humidity after bathing.

Drying the room

HUUM describes sauna ventilation as at least two and usually three parts: a supply pipe, an exhaust pipe and a drying opening. HUUM says the drying opening should be kept closed while the sauna is in use.

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