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casing. The construction of a heat storing sauna stove
differs from a continuously burning sauna stoves so
that there are no smoke channels in it. That means
the fire is in direct contact with the sauna stones,
before it exits through the chimney along with the
smoke. As the fire is in direct contact with the stones,
the heat is spread effectively to the stones giving the
stove an excellent efficiency and low temperatures
for the flue gas.
All this requires that the stones are under a closed
lid during the heat up. Otherwise the smoke would
escape to the sauna room, instead of the chimney.
During the sauna session, the lid can be opened in
order to pour water on the stones.
The “löyly” philosophy is completely different with a
heat storing sauna stove, as a great amount of heat
is stored in the stones. The sauna room has a rela-
tively low temperature when the room is entered.
This is because the stones are getting hot during the
heating, not the room itself, like it is with continu-
ously burning sauna stoves. There is no hot air circu-
lating between the stones and the room during the
heating. Most heat is stored in the stones, and some
heat will exit through the chimney. After the heating,
when the lid above the stones is opened, the even
the room gets hot. When “löyly” is being poured, the
very moist heat will feel quicker at the skin. As the
continuously burning stoves are much smaller than
heat storing stoves, the room must be heated up so
that there is warm enough during the sauna session.
The advantage of heat storing stove is that the room
temperature (can be around 55’C) is more pleasant
to enter. The correct sauna temperature and mois-
ture is then achieved by opening and closing the lid,
and by pouring water on the stones. After the sauna
session has ended or paused, the lid can be closed
to “reset” the sauna to lower temperature and drier
climate. The bigger the stove is, the more heat there
is for longer sauna sessions.
1.2 Materials
The casting is insulated, and the insulation is pro-
tected with rustproof sheet metal. The firebox is
made of fireproof mass and cast elements. The stone
compartment is lined with firebricks. The firebox
hatch, the grate and inner lid are made of cast iron.
1.3 Sauna stove stones
Suitable sauna stove stones are ceramic and olivine
stones.
1.4 Area of the steam room
If the walls of a steam room are made of uncovered
brick or concrete add 0.8–1.5 m
3
per square meter of
such wall and the final choice of the stove shall be
made based on the sum of the area.
If the stove is installed in a sauna that is normally not
heated or the sauna is made of massive logs, mul-
tiply the sauna area with 1.5 and choose the stove
based on this.
For sauna stoves AK 68–AK 110 the recommended
height of the sauna is 2700 mm as a minimum, so
the sauna bench remains high enough from the
surface of the sauna stove.
A space with a minimum
size of one meter must be left in front of the sauna
stove to facilitate maintenance of the firebox.
1.5 Substrate
AK sauna stoves must be installed on a stable, fire-
proof base.
NB! The surface temperature of the
floor tiles under the sauna stove may increase
to 250° C.
Keep this in mind to avoid any damage
caused to possible elements under the floor such as
insulation, piping, underfloor heating etc. Because
of the heat against the floor, concrete slab thickness
must be min 200mm. Please confirm safety from the
designer.
1.6 Smoke flue
NB! When connecting the sauna stove with the
smoke flue it has to be ensured that no excessive
load is applied on the sauna stove.
MASONRY SMOKE FLUE
According to the requirements of part E3 of the
Building Act concerning smoke flues, a masonry
smoke flue must be the so-called 1/1-brick flue for
AK 68-95 and 1 ½ brick flue for AK-110. The mini-
mum length of which measured on the smoke stove
is 3 meters.
MODULAR FLUE
A modular flue must meet the requirements of class
T600 and provided with CE-marking. When installing
a modular flue safety clearances stipulated in the
installation manual of the flue shall be followed. The
diameter of the modular flue shall be minimum
AK 68:150 mm, AK 78-95: 210mm and AK-110:
300mm. The minimum length of the chimney is 3m
measured from the top of the sauna stove.
