Harvia
Harvia M3 wood-burning sauna stove
Harvia makes the M3 wood stove in 2 versions for saunas of 212 ft³ to 459 ft³. Slide to your room size to see which one fits and how fast it heats.
Updated Oct 18, 2026
Output
not published
Rooms
212 ft³–459 ft³
Stones
66 lb
Sizes
2
Which size fits your sauna?
Your room's effective volume
335 ft³
Best fit: M3
Work out your effective volumeEffective volume = inside volume, plus 1.2 m³ for every m² of glass, tile or stone; × 1.5 for solid log walls (Harvia's rule, used by most planners).
Sizes and specifications
| Model | Output | Room range | Stones | Heat-up | Firewood per session |
|---|---|---|---|---|---|
| M3WKM3 | – | 212 ft³–459 ft³ | 66 lb | 25–35 min | 7 lb |
| M3 SLWKM3SL | – | 212 ft³–459 ft³ | 66 lb | 25–35 min | 7 lb |
Heat-up and cost are our heat model's estimate for each size in a room at the middle of its range: indoor, insulated walls, 68 °F around the sauna, heated to 176 °F, one hour of bathing, electricity at $0.18/kWh (United States average). The maker does not publish this stove's output; the heat-up times use a rough figure from its room range.
Where to see it
- M3 SL€786 at esaunashop.com (2026-10-18)
Prices and availability come from the shop or maker and change; their page is what counts. Shop offers are added as retailers join.
Sources
- esaunashop.com/harvia-m3-9349444dealer · read 2026-10-18
- esaunashop.com/harvia-m3-sldealer · read 2026-10-18
Other heaters for the same rooms
Questions and answers
What size sauna does the Harvia M3 heat?
Harvia rates the sizes for these rooms: M3 212 ft³–459 ft³; M3 SL 212 ft³–459 ft³. Use your room's effective volume: add 1.2 m³ for every m² of glass, tile or stone, and multiply by 1.5 for solid log walls.
How long does the Harvia M3 take to heat up?
In a well-insulated room at the middle of each size's range, our heat model gives about: M3 25–35 min; M3 SL 25–35 min to reach 176 °F. The maker does not publish the output, so treat these as rough; firing and wood make a big difference.
How many stones does the Harvia M3 take?
As stated by Harvia: M3 66 lb; M3 SL 66 lb. Use the stone size the manual specifies and re-stack the stones at least once a year, replacing crumbled ones.