Sauna heater – how many kW?

The sauna heater is the heart of every Sauna . It ensures that the desired temperature is reached and maintained in the sauna cabin. In general, the output of a sauna heater is given in kilowatts (kW). How many kW the sauna heater should have depends primarily on the size of the sauna. A sauna heater that is too weak costs a lot of warm-up time and a correspondingly large amount of energy, but a heater that is too strong also significantly reduces the sauna pleasure. That's why it's important to choose exactly the right stove.

Since the required sauna heater size depends mainly on the cabin size, the following table serves as an initial orientation for choosing the right sauna heater.

At Karibu, you can always find the sauna size in the product description of the individual sauna models. If you are looking for a sauna heater for an existing sauna, you can easily calculate the sauna size yourself. To do this, simply multiply the length of the cabin by its width and height to calculate the room volume.

Example calculation of cabin size

For a cabin size with a length of 200 cm, a width of 150 cm and a height of 200 cm, the calculation is as follows: 2 m x 1.5 m x 2 m = 6 m³. This means that the sauna has a size of 6 m³.

Other factors that affect the right stove size

In addition to the cabin size, other factors also affect how many kW your sauna heater should have. For example, if the sauna cabin has a glass door or glass wall or is poorly insulated, the heat is lost to the outside, so a stronger sauna heater is recommended. Especially in the case of a Garden sauna a lot of heat is lost, as it is usually colder outside than inside. Therefore, it is best to choose a powerful heater with 9 kW for a garden sauna.

If the size of the sauna heater is not right, this can have a negative effect on the sauna:
If the sauna heater is too weak, it takes a long time to heat up, which costs additional energy. In the worst case, the required temperature is not reached at all.
If the sauna heater is too strong, it heats up the air too quickly. The hot air rises much too quickly and the temperature sensor on the sauna ceiling already measures the desired temperature and switches off the heating process, although the temperature further down in the cabin has not yet been reached.
Buying a sauna heater with the right performance is therefore particularly important for a balanced sauna experience.

A 3.6 kW sauna heater is also called a plug and play heater. Such stoves have a lower output, but they do not require a high-voltage connection. So no electrician is necessary to connect a sauna heater with 3.6 kW, but a standard household 230 V socket is sufficient. Due to the low power, however, a small sauna heater with 3.6 kW is only suitable for a smaller Home sauna recommended. In addition, the maximum temperature is usually only a maximum of 80 °C, which is completely sufficient for sauna newcomers or heat-sensitive people.

A 9 kW sauna heater is recommended for larger saunas and garden saunas. The powerful high-voltage furnace must also be connected by an electrician. Due to the 9 kW power, pleasant temperatures of 100 °C and more can also be achieved in a large home sauna cabin or in a garden sauna.

The advantage of a 230 V sauna heater with only 3.6 kW is that no electrician is needed and the sauna heater can simply be connected to a standard household socket yourself. However, there are also restrictions: A 230V sauna heater is only available for saunas up to 6 m ³and only reaches a maximum temperature of 80 °C even with such small sauna cabins. If you want to enjoy a typical Finnish sauna pleasure at 100 °C or more, you should use a high-voltage heater.

The right sauna heater must fit the size of the sauna and the individual requirements. Only then can the selected sauna heater reach your personal desired temperature. A 3.6 kW sauna heater reaches a maximum of 80 °C in the sauna cabin, but can be connected to a standard household socket. It is therefore recommended for sauna beginners and heat-sensitive sauna-goers who want to buy a small indoor sauna. For larger saunas over 6 m ³and for all garden saunas, a powerful 9 kW stove is the right choice.

Yes, a sauna heater can also be too big. If a heater that is too strong is used for a small indoor sauna, the air in the cabin heats up too quickly and the temperature sensor on the sauna ceiling measures the desired temperature and switches off the heater, even though the rest of the cabin is still much too cold. Therefore, for smaller cabins, it is better to choose a stove with fewer kilowatts in order to be able to enjoy the full sauna pleasure.

You want to treat yourself to the luxury of your own sauna, but are you unsure whether the cost of a 9 kW sauna heater is worth it? We have compared the cost of a 9 kW sauna heater with that of a visit to a public sauna to help you decide. With a heating time of 60 minutes, the electricity consumption is 9 kWh per sauna session. With an electricity price of 0.40 euros per kWh, this is 3.60 euros per sauna session. Compared to a public sauna, this is much cheaper - especially if several people use the sauna or if you want to enjoy your sauna more than once a week.