Running cost calculator

Start with three details: your heater’s power rating, your electricity unit rate and the total time the heater runs. Use the rate from your energy bill rather than treating a supplier’s example tariff as your own.

The basic calculation is:

- Heater power in kW × running time in hours = energy in kWh. - Energy in kWh × electricity price in £ per kWh = estimated session cost.

Keep the units consistent. Palmako’s example converts 24.86p per kWh to £0.2486 per kWh before calculating the cost. A price in pence should not be entered as though it were pounds.

This gives a full-power estimate. It is a useful starting point for budgeting, but it does not account for a thermostat switching the heating elements on and off once the sauna reaches its target temperature.

Your heater uses electricity before you enter the sauna. Leaving that period out makes the estimate incomplete. Add warm-up time to the period of use, then express the total in hours.

Palmako works through a traditional electric sauna example with a 6 kW heater:

- Warm-up: 30 minutes, or 0.5 hours. - Sauna use: 1 hour. - Total running time: 1.5 hours. - Energy: 6 kW × 1.5 hours = 9 kWh. - Cost: 9 kWh × £0.2486 = approximately £2.24.

Sources differ on heating time. Palmako describes a typical electric warm-up of 20–30 minutes. Harvia describes an initial full-power period of 30–40 minutes, while its longer energy example allows about an hour for heating. These are not interchangeable assumptions. Use the warm-up time relevant to your sauna rather than applying one example to every cabin.

The simple formula assumes the heater draws its rated power throughout the whole period. In practice, the thermostat regulates the heating elements to maintain the selected temperature.

Harvia says power output falls to about half the maximum after the initial full-power heating phase. Its example of a well-insulated sauna with a suitable 6 kW heater uses about 4–5 kWh in the first hour and 3–4 kWh in the next. That totals 7–9 kWh over two hours.

This differs from Palmako’s full-power calculation, which uses 9 kWh over 1.5 hours. The examples use different assumptions about heating time and power demand. They should not be read as identical sessions with conflicting prices.

Insulation, sauna size and temperature setting also affect consumption. Nuovo Luxury additionally identifies outdoor temperature and how often the door opens. Treat a calculator result as an estimate, not a guaranteed bill.

The Hot Tub Superstore gives a 6 kW electric heater example costing £1.32 for an hour at £0.22 per kWh. Its 1.5 kW infrared example costs £0.33 for an hour at the same tariff. These are hourly comparisons, so account for any additional warm-up time when planning a complete session.

Palmako includes warm-up in its infrared calculation. A 1.5 kW heater operating for 1.25 hours uses 1.875 kWh. At £0.2486 per kWh, the estimated cost is £0.47.

The tariff assumptions also differ: The Hot Tub Superstore uses 22p per kWh, while Palmako uses 24.86p. Neither should replace the rate on your bill.

For a specific product, use its stated rating. Zauna’s checked heater records list the PYRY Electric Sauna Heater by Tulikivi and HUUM DROP Electric Sauna Heater at 4.5 kW. The Narvi NC Domestic Electric Sauna Heater (Wi-Fi) is listed at 6 kW.

Multiply your estimated session cost by how often you expect to use the sauna. Keep the usage assumption visible: a daily-use example is not a suitable monthly budget if you only plan occasional sessions.

Palmako’s traditional electric example gives £15.68 per week and £68.19 per month. Those figures assume daily use at approximately £2.24 per session. They are not general monthly prices for every home sauna.

Keep electricity and servicing separate. The Hot Tub Superstore quotes annual sauna servicing at £50–£200, depending on size and system type. That cost is not included in the heater-power formula.

To limit unnecessary heating, Harvia advises using the sauna once it is hot enough and turning the heater off after use. A slightly lower temperature can also reduce consumption. Nuovo Luxury warns that keeping a sauna warm on standby can raise costs, especially over longer periods.