Sauna heaters are rated in kilowatts, and the right number comes from the volume of the room — length × width × height — not its floor area. Get it wrong low and the room never really gets there. Get it wrong high and you waste power and overshoot.
The baseline rule
For a well-insulated timber sauna, allow roughly 1kW per 45–50 cubic feet (1.3–1.4 m³) of room volume.
Worked example: a room 6ft × 5ft × 7ft is 210 cubic feet. 210 ÷ 45 ≈ 4.7, so a 4.5kW to 6kW stove is the right bracket.
Quick reference
- Up to ~160 cu ft — 3kW
- ~160–250 cu ft — 4.5kW
- ~250–320 cu ft — 6kW
- ~320–460 cu ft — 9kW
The Succebuy electric sauna stove is available across this whole range, 3kW to 9kW at 220V.
When to size up
Add capacity for anything that loses heat faster than insulated timber:
- Glass. A full glass door or a panoramic wall is a significant heat loss. Add roughly 1kW per 10–15 sq ft of glass.
- Uninsulated or masonry walls. Stone, tile and concrete absorb a great deal of heat before the air gets warm. Size up a full bracket.
- Cold climates and outdoor rooms. A sauna in a Minnesota winter is not the same load as one in a heated basement.
- High ceilings. Already handled if you calculated volume rather than floor area — which is exactly why you should.
The electrical reality
This is the part that catches people out. Sauna stoves at these outputs are hardwired 220V appliances on a dedicated circuit, not something you plug in. A 9kW heater draws serious current and needs breaker and cable sized to match.
Have a licensed electrician specify and install the circuit, and get that quote before you choose the heater — the wiring can be a meaningful fraction of the total cost, and it is the thing that determines whether 9kW is even practical at your panel.
Stones matter more than people expect
The rock tray is not decoration. Stones store heat and release it as soft steam when you ladle water — the difference between a hot room and a sauna. Fill the tray properly, leave gaps for airflow, and replace stones when they start crumbling.
Round out the room with a bucket, ladle, thermometer and timer set, or a combined thermometer and hygrometer so you can actually read the room.
See the full sauna range.
General guidance for setting up home equipment. Not medical advice — talk to a doctor before starting cold or heat exposure, especially with heart, blood pressure or pregnancy considerations.
