Harvia Pro 20 24.1 kW Wood-Burning Sauna Stove

The Harvia Pro 20 is a 24.1 kW wood-burning sauna stove for rooms of 283–706 cubic feet. It takes 88 lb of 10-15cm sauna stones (sold separately), needs no electrical supply, and requires a code-compliant chimney.

The Pro is the workhorse of Harvia's wood-burning range: a heavy steel firebox with an open stone bed, built to be specified around the room rather than the other way round. Wood sauna layout is nearly always constrained by something — where the chimney can run, whether you can feed the fire from outside the hot room, whether you need hot wash water without a second heater. Harvia builds this firebox in the configurations that solve those constraints without forcing you to change stove size.

These are not included. You need them before the sauna will run.

Harvia lists this model with CE, EAC marks. These are the European and Eurasian conformity marks, not a UL or ETL listing for North America — confirm requirements with your building department and insurer.

The Harvia Pro 20 is rated for 283–706 adjusted cubic feet.

Adjusted cubic feet = width × depth × height in feet, plus 45 cu ft for every square foot of glass, tile, concrete or stone, plus 15 cu ft for every square foot of exposed log wall. A 6 × 7 ft room with a 7 ft ceiling is 294 raw cu ft — add a full-glass door and it becomes 834. Always size to the adjusted number.

Work out your room with the sauna heater size calculator

• Confirm the flue diameter and whether your chimney connects top or rear before you order chimney components. This is the most common ordering mistake on wood sauna builds.
• Harvia wood stoves use 115 mm (4.5 in) European flue pipe. A North American 6 in chimney needs the Harvia WZ115155 adapter.
• A solid-fuel appliance usually needs a permit and an inspection in the US, and your insurer will normally want to see the sign-off.
• Burn the stove outdoors or with the room ventilated for the first firing to cure the paint. Load stones loosely by hand and re-stack them once a year.
• This is an LTL freight item. It arrives curbside on a pallet and the carrier calls to book a window — have two people and a pallet jack or dolly ready, and note any damage on the delivery receipt before you sign.
• Stones ship separately on their own freight because of the weight.

Will the Harvia Pro 20 connect to a US chimney?

Not directly. Harvia wood stoves are built with 115 mm (4.5 in) European flue pipe, so a North American 6 in system needs the Harvia WZ115155 adapter. Confirm your flue diameter and whether the connection is top or rear before ordering.

Can the Harvia Pro 20 sit on a wooden floor?

Only with the floor protection the installation manual specifies, and only at the clearances it gives. A Harvia protective shield reduces those clearances, but only by the stated amount and only when it is the shield listed for this stove.

How long does the Harvia Pro 20 take to heat up?

Harvia does not publish a figure. As a rule of thumb a correctly sized, well-insulated room with a full stone charge is ready 45 to 75 minutes after lighting, and the stones keep giving heat back long after the fire dies down.