Commercial wood-burning stoves for large public saunas
P.08Commercial
Pro 20 / Pro 36 (WK-series)
Specs from harvia.com and Harvia Plc materials, in US units. Check the current Harvia manual before you wire or install.
31 kW of wood-fired output for rooms up to 1,270 cu ft, built in Finland for large public and destination saunas.
Pro 20 (WK200) and Pro 36 (WK360) are the commercial-scale wood-burning stoves Harvia builds for public saunas, resorts, and large communal installations. Pro 36 is the headline unit: 31 kW equivalent output, rooms up to 1,270 cubic feet, 132 lbs of stones stacked in three tiers, and a fire chamber that accepts firewood up to 15.3 inches long. These heaters end up in Nordic bathhouses, ski-town communal saunas, and destination wellness properties. The minimum ceiling spec is 81 inches, scaled for commercial rooms rather than residential ones.
Commercial and destination wood-fired saunas, ski-town communal bathhouses, Nordic-inspired resort installs, large private cabin builds where the operator wants the Finnish commercial experience. Rooms 500+ cu ft with 81+ inch ceilings.
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.
“Muurame factory, the world's largest heater and sauna component factory: over 150,000 heaters per year.”
Harvia Capital Markets Day 2024 presentation
Pro 20 and Pro 36 are produced at Harvia's Muurame, Finland factory alongside the rest of the wood-burning heater line
“In 2023, manufacturing [of wood-burning heaters] was almost fully moved to Muurame.”
Harvia Plc 2023 Annual Report
After Harvia's 2022 exit from Russia, wood-burning heater production including the commercial Pro series was reshored to Finland
Check each note against the current Harvia manual and your local code.
N.01
Pro 36's 81-inch ceiling requirement comes from flue clearance and radiant heat distribution. In rooms with 78-inch ceilings you get hot spots at head height and insufficient steam at bench height. Spec Pro 20 (or Legend 240SL) instead if the ceiling can't clear 81 inches.
N.02
Both compete in the 700-1,200 cu ft range. Pro 36 has the larger fire chamber (fast heat-up, shorter recovery between sessions) but smaller stone capacity (132 lbs vs 450 lbs). Legend 240SL has the external wood-feed door that commercial operators prefer for safety. If the operator wants fast room turnaround, Pro 36 wins. If the operator values safety and consistent steam recovery across a long service day, Legend 240SL.
N.03
At 31 kW output, flue gas temperatures run 600-800°F during active burning. Single-wall pipe is not rated for that. Every commercial Pro 36 install requires full insulated Class A from heater collar to termination above the roof. Budget $2,500-$4,500 for the chimney package alone. Single-wall pipe on this output is code violation and fire hazard.
N.04
Pro 36 stones in commercial rooms running 12+ hours a day need full reload at 18-24 months. The firebox is not the problem; thermal cycling breaks down the stones themselves. Budget the reload into operations schedule or the room loses steam output gradually without the operator noticing.
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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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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