Rated for a bigger room: Kuuma Classic Legacy (Small)
Kuuma rates it for 336–512 ft³ (about 9.5–14.5 m³, our conversion); Harvia rates the M3 wood-burning heater for 212–459 ft³ (about 6–13 m³, our conversion).
Harvia M3 wood-burning heater
A 16.5 kW wood-burning sauna stove from Harvia, rated by the maker for 212–459 ft³ (about 6–13 m³, our conversion). Every figure below is Harvia's own, linked to where it is published.
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Specifications published by Harvia (9)
- Heater output
- 16.5 kWWood burning heater Harvia M3 black | Wood burning heaters | Harvia
- Room size it is rated for
- 212–459 ft³ (about 6–13 m³, our conversion)Wood burning heater Harvia M3 black | Wood burning heaters | Harvia
- Stone capacity
- 66.2 lbWood burning heater Harvia M3 black | Wood burning heaters | Harvia
- Dimensions
- H 27.95 in x W 15.35 in x D 17.72 inWood burning heater Harvia M3 black | Wood burning heaters | Harvia
- Water tank
- Optional pipe-model water heaterWood burning heater Harvia M3 black | Wood burning heaters | Harvia
As published by Harvia, read on 2026-09-22. Makers revise their products; check Harvia's current specification before you buy. Figures marked "about" are Saunakivi's unit conversions of the maker's figure.
Before you buy
- Room size. Our heater sizing guide explains how makers adjust the rated room size for glass and uninsulated walls.
- Wood or electric. Our wood vs electric guide sets out what each needs to install.
If you are looking for more
Compare it with
M3 wood-burning heater vs HIVE Wood 13
Side by side with the HUUM HIVE Wood 13. These wood-burning stoves carry maker room-size ratings that share part of the same range.
M3 wood-burning heater vs Classic Legacy (Small)
Side by side with the Kuuma Classic Legacy (Small). Both are wood-burning stoves, and the room sizes their makers rate them for overlap.
M3 wood-burning heater vs Low Profile (Small)
Side by side with the Kuuma Low Profile (Small). Both are wood-burning stoves, and the room sizes their makers rate them for overlap.
Other wood-burning stoves
Harvia Pro 20 ES wood-burning heater
Harvia · wood-burning · 24.1 kW · rated for 283–706 ft³ (about 8–20 m³, our conversion)
Harvia Legend 150 wood-burning heater
Harvia · wood-burning · 16 kW · rated for 6–13 m³ (about 212–459 ft³, our conversion)
HUUM HIVE Wood 13
HUUM · wood-burning · 13 kW · rated for 6–13 m³ (about 212–459 ft³, our conversion)
HUUM HIVE Flow
HUUM · wood-burning · 9.8 kW · rated for 8–18 m³ (about 283–636 ft³, our conversion)
Kuuma Classic Legacy (Medium)
Kuuma · wood-burning · rated for 512–780 ft³ (about 14.5–22.1 m³, our conversion)
Kuuma Low Profile (Medium)
Kuuma · wood-burning · rated for 448–700 ft³ (about 12.7–19.8 m³, our conversion)
M3 wood-burning heater: questions answered from Harvia's specification
What is the output of the M3 wood-burning heater?
Harvia lists 16.5 kW. Related question: What size sauna heater do I need?
Source: Wood burning heater Harvia M3 black | Wood burning heaters | Harvia
What size of sauna room is the M3 wood-burning heater for?
Harvia rates it for 212–459 ft³ (about 6–13 m³, our conversion). See our heater sizing guide for how makers adjust that figure for glass and uninsulated walls. Related question: Wood-burning sauna stoves: which room size is each rated for?
Source: Wood burning heater Harvia M3 black | Wood burning heaters | Harvia
How many stones does the M3 wood-burning heater hold?
Harvia lists a stone capacity of 66.2 lb.
Source: Wood burning heater Harvia M3 black | Wood burning heaters | Harvia
Can the M3 wood-burning heater heat water?
Harvia lists: Optional pipe-model water heater.
Source: Wood burning heater Harvia M3 black | Wood burning heaters | Harvia
More from Harvia: all Harvia products on Saunakivi.