HUUM
HUUM Steel sauna heater
HUUM makes the Steel in 4 sizes, from 3.5 to 11 kW, for saunas of 106 ft³ to 565 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 17, 2026
Output
3.5–11 kW
Rooms
106 ft³–565 ft³
Stones
132 lb–331 lb
Sizes
4
Which size fits your sauna?
Your room's effective volume
247 ft³
Best fit: 6
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 |
|---|---|---|---|---|---|
| STEEL Mini 4 | 3.5 kW | 106 ft³–177 ft³ | 132 lb | 85–115 min | $1.20 |
| STEEL 6 | 6 kW | 177 ft³–318 ft³ | 331 lb | 85–115 min | $1.88 |
| STEEL 9 | 9 kW | 283 ft³–459 ft³ | 331 lb | 60–80 min | $2.22 |
| STEEL 11 | 11 kW | 353 ft³–565 ft³ | 331 lb | 50–70 min | $2.41 |
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 |
|---|---|---|---|---|
| STEEL Mini 4 | 1~ 240 V | 14.6 A | 20 A | 12 AWG |
| STEEL 6 | 1~ 240 V | 25 A | 30 A | 10 AWG |
| STEEL 9 | 1~ 240 V | 37.5 A | 50 A | 8 AWG |
| STEEL 11 | 1~ 240 V | 45.8 A | 50 A | 6 AWG |
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
Prices and availability come from the shop or maker and change; their page is what counts. Shop offers are added as retailers join.
Sources
- huum.eu/product/steel-mini-electric-sauna-heater/maker · read 2026-10-17
- huumsauna.com/product/steel-mini-electric-sauna-heater/maker · read 2026-10-17
- huum.eu/product/steel-electric-sauna-heater/maker · read 2026-10-17
- huumsauna.com/product/steel-electric-sauna-heater/maker · read 2026-10-17
Other heaters for the same rooms
Questions and answers
What size sauna does the HUUM Steel heat?
HUUM rates the sizes for these rooms: STEEL Mini 4 106 ft³–177 ft³; STEEL 6 177 ft³–318 ft³; STEEL 9 283 ft³–459 ft³; STEEL 11 353 ft³–565 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 HUUM Steel need?
It depends on the size and your supply: STEEL Mini 4: 1~ 240 V: 14.6 A (20 A); STEEL 6: 1~ 240 V: 25 A (30 A); STEEL 9: 1~ 240 V: 37.5 A (50 A); STEEL 11: 1~ 240 V: 45.8 A (50 A). A licensed electrician sizes the circuit from the heater's manual and local rules.
How long does the HUUM Steel take to heat up?
In a well-insulated indoor room at the middle of each size's range, our heat model gives: STEEL Mini 4 85–115 min; STEEL 6 85–115 min; STEEL 9 60–80 min; STEEL 11 50–70 min to reach 176 °F. Outdoor saunas, glass and cold weather take longer.
How many stones does the HUUM Steel take?
As stated by HUUM: STEEL Mini 4 132 lb; STEEL 6 331 lb; STEEL 9 331 lb; STEEL 11 331 lb. Use the stone size the manual specifies and re-stack the stones at least once a year, replacing crumbled ones.