Harvia
Harvia Forte sauna heater
Harvia makes the Forte in 2 sizes, from 6 to 9 kW, for saunas of 247 ft³ to 530 ft³. Slide to your room size to see which one fits, how fast it heats and what it needs from your fuse box.
Updated Oct 18, 2026
Output
6–9 kW
Rooms
247 ft³–530 ft³
Stones
220 lb
Sizes
2
Which size fits your sauna?
Your room's effective volume
335 ft³
Best fit: AFB6
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 | Per session |
|---|---|---|---|---|---|
| Forte AFB6HAFB600400M, HAFB600400S | 6 kW | 247 ft³–424 ft³ | 220 lb | 80–105 min | $1.94 |
| Forte AFB9HAFB900400M, HAFB900400S | 9 kW | 353 ft³–530 ft³ | 220 lb | 55–70 min | $2.11 |
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).
Electrical connection
| Model | Supply | Current | Fuse / breaker | Cable |
|---|---|---|---|---|
| Forte AFB6 | 3~ 400 V | 8.7 A | – | – |
| Forte AFB9 | 3~ 400 V | 13 A | – | – |
Current is computed from the output; fuse and cable are shown where the maker or dealer states them. A licensed electrician sizes and installs the circuit following the heater's manual and local rules.
Where to see it
- Forte AFB6€1,568 at esaunashop.com (2026-10-18)
- Forte AFB6€1,568 at esaunashop.com (2026-10-18)
- Forte AFB9€1,689 at esaunashop.com (2026-10-18)
- Forte AFB9€1,689 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-forte-black-6kwdealer · read 2026-10-18
- esaunashop.com/harvia-forte-steel-6kwdealer · read 2026-10-18
- esaunashop.com/harvia-forte-black-9kwdealer · read 2026-10-18
- esaunashop.com/harvia-forte-steel-9kwdealer · read 2026-10-18
Other heaters for the same rooms
Questions and answers
What size sauna does the Harvia Forte heat?
Harvia rates the sizes for these rooms: Forte AFB6 247 ft³–424 ft³; Forte AFB9 353 ft³–530 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.
What fuse or breaker does the Harvia Forte need?
It depends on the size and your supply: Forte AFB6: 3~ 400 V: 8.7 A; Forte AFB9: 3~ 400 V: 13 A. A licensed electrician sizes the circuit from the heater's manual and local rules.
How long does the Harvia Forte take to heat up?
In a well-insulated indoor room at the middle of each size's range, our heat model gives: Forte AFB6 80–105 min; Forte AFB9 55–70 min to reach 176 °F. Outdoor saunas, glass and cold weather take longer.
How many stones does the Harvia Forte take?
As stated by Harvia: Forte AFB6 220 lb; Forte AFB9 220 lb. Use the stone size the manual specifies and re-stack the stones at least once a year, replacing crumbled ones.