The size of an electric sauna heater is usually indicated by the heater's power in kilowatts (kW). The power of a sauna heater depends on the size of the sauna and other factors such as insulation, ceiling height, room temperature and ventilation.
A general rule of thumb is that a sauna heater with an output of 1 kW is sufficient per 1 - 1.5 cubic metres of sauna volume.
However, it is important to note that this rule of thumb is only a rough estimate and that the actual power required for a particular sauna size may depend on various factors. Professional advice or an exact calculation by an expert can help determine the optimal size of the sauna heater for a particular sauna.
General guidelines: (width x height x depth = volume of the sauna indoors)
4.5 kW sufficient for 3 - 6 m³ cabin volume
6.0 kW sufficient for 5 - 9 m³ cabin volume
8.0 kW sufficient for 8 - 11 m³ cabin volume
9.0 kW sufficient for 10 - 14 m³ cabin volume
If the sauna cabin is located in the cellar where it is colder, in the summer house or if the sauna has a lot of glass surface, then the sauna heater should be selected stronger.