The 40 kW commercial wood-fired stove sized for large public saunas
P.12Commercial
Harvia 50 / WK500
Specs from harvia.com and Harvia Plc materials, in US units. Check the current Harvia manual before you wire or install.
Harvia's largest wood-burning stove. 40 kW rated output, 264 lbs of stone capacity, steel construction, black finish. Rated by Harvia for sauna rooms from 706 to 1,766 cubic feet and designated for professional use.
The Harvia 50 (model WK500) is the largest wood-burning sauna heater in Harvia's current catalog. It is rated at 40 kW output, holds 264.6 lbs of stones in a size range of roughly 4-6 inches, and Harvia's spec places it in sauna rooms from 706 to 1,766 cubic feet. The stove is designated for professional user groups and is built for commercial and destination-scale wood-fired saunas: large public bathhouses, ski-town communal saunas, resort wellness facilities, and multi-session commercial operations. Floor-mounted, steel construction, black finish. Minimum room height is 6.56 ft, and Harvia specifies meaningful safety-distance setbacks from combustible materials (see the spec sheet linked below). Manufactured in Harvia's Muurame, Finland factory.
Large commercial wood-fired saunas, destination and public bathhouses, ski-town communal rooms, and commercial wellness installations in rooms Harvia's own spec places at 706-1,766 cu ft. Not specified by Harvia for residential use; residential wood-fired buyers should look at the Harvia 20, Harvia 36, Legend 150, or Cilindro wood-burning instead.
Editorial analysis for context, not a purchase recommendation.
Room sizes in cubic feet, stone loads in pounds.
From earnings calls, investor presentations, annual reports, and the Harvia catalog.
“The heater is a Harvia 50, the Finnish manufacturer's largest wood-burning stove.”
SaunaNews, April 2026
White Mountain Sauna Haus (North Conway, NH) commercial bathhouse install
Check each note against the current Harvia manual and your local code.
N.01
Harvia's own product classification designates the Harvia 50 as a professional-user product. It is sized and rated for very large sauna rooms (706-1,766 cu ft per Harvia's spec sheet) and for commercial use patterns. For residential wood-fired installations, Harvia's smaller wood-burning heaters (the 20, 36, Legend 150, or Cilindro wood-burning) are the more appropriate choice.
N.02
The Harvia 50 spec sheet lists specific safety distances from combustible and non-combustible surfaces at the front, sides, back, and ceiling. These distances are larger than for smaller Harvia wood-burning heaters and should be followed exactly. For a 40 kW stove running in a commercial duty cycle, getting safety-distance clearances right is the most important thing the install will get right.
N.03
Harvia specifies roughly 4-6 inch stones for the Harvia 50, larger than the 2-4 inch stones used in smaller Harvia heaters like KIP or Vega. At commercial output, smaller stones can fracture under thermal load and pack down, cutting airflow and steam output. Use the Harvia-specified stone size range and plan for periodic stone replacement under heavy commercial use.
Product, detail, and technical images from the Harvia Media Bank.
Images: Harvia Media Bank, courtesy of Harvia Plc, unless the caption says otherwise.
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Commercial wood-burning stoves for large public saunas
Product data comes from Harvia Plc investor materials, earnings call transcripts, harvia.com, and harviagroup.com. Quotes carry their source where a public one exists. SaunaNews is not affiliated with Harvia Plc; this page is a product record for news coverage, not a sales page. Spot an error or an outdated spec? Tell the newsroom .
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