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The 40 kW commercial wood-fired stove sized for large public saunas
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 Ø10-15 cm, 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 ceiling clearance 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.
Model
WK500
Power output
40 kW
Stone capacity
264.6 lbs
Room size
706 – 1,766 cu ft
Min ceiling height
6.56 ft (2 m)
Stone size
Ø10 – 15 cm
Net weight
428.2 lbs
Dimensions (HxWxD)
3.44 ft × 20.08 in × 28.35 in
Construction
Steel, black finish
User group
Professional
Made in
Muurame, Finland
| Model | Power | Room size | Stones | Voltage | Notes |
|---|---|---|---|---|---|
| Harvia 50 (WK500) | 40 kW | 706 – 1,766 cu ft | 264.6 lbs | — | Floor-mounted, black steel, designated for professional use |
From earnings calls, investor presentations, annual reports, and the Harvia product catalog.
“The heater is a Harvia 50, the Finnish manufacturer's largest wood-burning stove.”
Field knowledge from specialty dealers, commercial installers, and long-term Harvia operators. Stuff that isn't on the spec sheet.
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.
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.
Harvia specifies Ø10-15 cm stones for the Harvia 50 — larger than what's 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.
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.
Warranty
Per Harvia commercial terms
Made in
Muurame, Finland
Launched
WK500 is the current generation of Harvia's largest wood-burning stove
Last Harvia mention
April 16, 2026
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Product data sourced from Harvia Plc investor materials, earnings call transcripts, harvia.com, and harviagroup.com. Quotes attributed to specific sources. Insider notes reflect field knowledge from specialty dealers and commercial installers. SaunaNews is independent and not affiliated with Harvia Plc.