IKI
IKI Monolith sauna heater
IKI makes the Monolith in 5 sizes, from 6.9 to 18 kW, for saunas of 247 ft³ to 989 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
6.9–18 kW
Rooms
247 ft³–989 ft³
Stones
265 lb–485 lb
Sizes
5
Which size fits your sauna?
Your room's effective volume
706 ft³
Best fit: 13.8 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 |
|---|---|---|---|---|---|
| Monolith 6.9 kW | 6.9 kW | 247 ft³–424 ft³ | 265 lb | 70–100 min | $2.02 |
| Monolith 9 kW | 9 kW | 318 ft³–565 ft³ | 265 lb | 60–80 min | $2.36 |
| Monolith 13.8 kW | 13.8 kW | 530 ft³–883 ft³ | 485 lb | 65–90 min | $3.67 |
| Monolith 15.9 kW | 15.9 kW | 565 ft³–918 ft³ | 485 lb | 55–75 min | $3.75 |
| Monolith 18 kW | 18 kW | 636 ft³–989 ft³ | 485 lb | 50–65 min | $3.85 |
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 |
|---|---|---|---|---|
| Monolith 6.9 kW | 3~ 400 V | 10 A | – | – |
| Monolith 9 kW | 3~ 400 V | 13 A | – | – |
| Monolith 13.8 kW | 3~ 400 V | 19.9 A | – | – |
| Monolith 15.9 kW | 3~ 400 V | 22.9 A | – | – |
| Monolith 18 kW | 3~ 400 V | 26 A(computed) | – | – |
| 1~ 230 V | 78.3 A(computed) | – | – |
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
- esaunashop.com/electric-sauna-heater-iki-monolith-6-9-kwdealer · read 2026-10-18
- esaunashop.com/electric-sauna-heater-iki-monolith-9-kwdealer · read 2026-10-18
- esaunashop.com/electric-sauna-heater-iki-monolith-13-8-kwdealer · read 2026-10-18
- esaunashop.com/electric-sauna-heater-iki-monolith-15-9-kwdealer · read 2026-10-18
- esaunashop.com/electric-sauna-heater-iki-monolith-18-kwdealer · read 2026-10-18
Other heaters for the same rooms
Questions and answers
What size sauna does the IKI Monolith heat?
IKI rates the sizes for these rooms: Monolith 6.9 kW 247 ft³–424 ft³; Monolith 9 kW 318 ft³–565 ft³; Monolith 13.8 kW 530 ft³–883 ft³; Monolith 15.9 kW 565 ft³–918 ft³; Monolith 18 kW 636 ft³–989 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 IKI Monolith need?
It depends on the size and your supply: Monolith 6.9 kW: 3~ 400 V: 10 A; Monolith 9 kW: 3~ 400 V: 13 A; Monolith 13.8 kW: 3~ 400 V: 19.9 A; Monolith 15.9 kW: 3~ 400 V: 22.9 A; Monolith 18 kW: 3~ 400 V: 26 A, 1~ 230 V: 78.3 A. A licensed electrician sizes the circuit from the heater's manual and local rules.
How long does the IKI Monolith take to heat up?
In a well-insulated indoor room at the middle of each size's range, our heat model gives: Monolith 6.9 kW 70–100 min; Monolith 9 kW 60–80 min; Monolith 13.8 kW 65–90 min; Monolith 15.9 kW 55–75 min; Monolith 18 kW 50–65 min to reach 176 °F. Outdoor saunas, glass and cold weather take longer.
How many stones does the IKI Monolith take?
As stated by IKI: Monolith 6.9 kW 265 lb; Monolith 9 kW 265 lb; Monolith 13.8 kW 485 lb; Monolith 15.9 kW 485 lb; Monolith 18 kW 485 lb. Use the stone size the manual specifies and re-stack the stones at least once a year, replacing crumbled ones.