EOS
EOS Bi-O Mini W sauna heater
The EOS Bi-O Mini W is a 3.5 kW heater that EOS rates for saunas of 106 ft³ to 141 ft³. Check it against your room, see how fast it heats and what it needs from your fuse box.
Updated Oct 18, 2026
Output
3.5 kW
Rooms
106 ft³–141 ft³
Stones
18 lb
Sizes
1
Which size fits your sauna?
Your room's effective volume
124 ft³
Best fit: 3.5 kW
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 |
|---|---|---|---|---|---|
| Bi-O Mini W 3.5 kW94.6027 | 3.5 kW | 106 ft³–141 ft³ | 18 lb | 30–40 min | $0.71 |
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 |
|---|---|---|---|---|
| Bi-O Mini W 3.5 kW | 1~ 230 V | 15.2 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
- Bi-O Mini W 3.5 kW€699 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/electric-sauna-heater-eos-bi-o-mini-w-3-0-kwdealer · read 2026-10-18
Other heaters for the same rooms
Questions and answers
What size sauna does the EOS Bi-O Mini W heat?
EOS rates the sizes for these rooms: Bi-O Mini W 3.5 kW 106 ft³–141 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 EOS Bi-O Mini W need?
It depends on the size and your supply: Bi-O Mini W 3.5 kW: 1~ 230 V: 15.2 A. A licensed electrician sizes the circuit from the heater's manual and local rules.
How long does the EOS Bi-O Mini W take to heat up?
In a well-insulated indoor room at the middle of each size's range, our heat model gives: Bi-O Mini W 3.5 kW 30–40 min to reach 176 °F. Outdoor saunas, glass and cold weather take longer.
How many stones does the EOS Bi-O Mini W take?
As stated by EOS: Bi-O Mini W 3.5 kW 18 lb. Use the stone size the manual specifies and re-stack the stones at least once a year, replacing crumbled ones.