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Sauna heater sizing calculator

Room size in, matching heaters out. Works for electric and wood-burning heaters.

STEEL Mini 4106–177 cu ft $1,576 CLIFF Mini 4123–212 cu ft $2,003 DROP 6177–318 cu ft $1,506 STEEL 6177–318 cu ft $2,033 CLIFF 6177–318 cu ft $2,347 HIVE Mini 6177–318 cu ft $2,502 HIVE Wood 13212–459 cu ft $2,150 HIVE Flow Mini212–494 cu ft $2,898 HIVE Flow Mini LS212–494 cu ft $3,008 HIVE Flow282–635 cu ft $3,129 HIVE Flow LS282–635 cu ft $3,221 DROP 9283–460 cu ft $1,751 STEEL 9283–460 cu ft $2,224 HIVE Wood 17283–565 cu ft $2,350 CLIFF 9283–460 cu ft $2,638 HIVE Mini 9283–460 cu ft $2,657 STEEL 11354–566 cu ft $2,391 HIVE Mini 11354–566 cu ft $2,785 CLIFF 11354–566 cu ft $2,879 HIVE 12424–636 cu ft $2,848 HIVE 15530–813 cu ft $3,088 HIVE 18636–989 cu ft $3,356

Fits your roomElectricWood-burningYour room

How the math works

Start with the room’s volume: length times width times height, in feet. A 7 × 6 × 7 ft room is 294 cubic feet.

Glass, stone and other uninsulated surfaces pull heat out of the room, so they count as extra volume. Heater maker Harvia’s rule is that each square meter of glass or stone adds the load of 1.2 cubic meters of room, which works out to about 3.9 cubic feet for every square foot. A glass door of about 17 square feet adds roughly 67 cubic feet.

Bare log walls hold heat differently, and the same guidance raises the factor to 1.5 for uninsulated log interiors. The calculator multiplies the whole volume by 1.5 when you tick that box.

Then pick a heater whose rated range includes your number. If you land near the top of a heater’s range, the next size up heats faster. Electric heaters need a dedicated 240 V circuit sized by an electrician.

Source: Harvia, How do I select the correct heater power. Room ranges are the manufacturer’s published ratings for each heater.

Free: Sauna Heater Buyer’s Worksheet

Work out your room’s heating volume, see every HUUM heater rated for it, and hand your electrician the breaker and wire sizes.