How Much Does A Sauna Cost to Run in the UK?

Having a sauna in your backyard is the ultimate luxury, but with rising energy costs you may be wondering if it’s a luxury beyond your reach, even if it has amazing health benefits. 

Join us as we explore the facts and provide you with ways to decrease the cost of operating home saunas. 

Calculate the cost of running a sauna session

Traditional electric saunas

To calculate the cost of running a 6 kW electric heater for home saunas in the United Kingdom, we'll consider both the warm-up period and the duration of the sauna session. Here's how we can estimate the total cost:

1. Determine the total operational time

• Warm-up period: Electric saunas typically require between 20 to 30 minutes to reach the desired temperature. For this calculation, we'll assume a 30-minute (0.5 hours) warm-up period.
• Sauna session: 1 hour.
• Total time: 0.5 hours (warm-up) + 1 hour (session) = 1.5 hours.

2. Calculate the total energy consumption:

• The heater's power rating is 6 kW.
• Total energy consumed = Power (kW) × Time (hours) = 6 kW × 1.5 hours = 9 kWh.
• Find the current electricity cost per kWh: As of January 2025, the average electricity unit rate in the UK is 24.86 pence per kWh. 

3. Calculate the total cost:

• Convert the unit rate to pounds: 24.86 pence = £0.2486.
• Total cost = Energy consumed (kWh) × Cost per kWh (£) = 9 kWh × £0.2486 = £2.24.

Therefore, the estimated cost to run a 6 kW electric sauna heater for a 30-minute warm-up period followed by a 1-hour session is approximately £2.24.

Based on this calculation, the cost of running a sauna is as follows:

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Infrared sauna

An infrared indoor sauna uses infrared light to warm your body rather than heating the air around you. They use heating elements that lower the ambient temperature to around 40–60 °C (104–140 °F) compared to 70–90 °C (158–194 °F) in traditional saunas. [1] For this reason, they are generally more energy efficient, and the running costs are lower than a traditional sauna.

Electricity usage for an infrared sauna is less due to:

• Energy consumption: These saunas use heaters rated between 1kW and 1.5kW.
• Warm-up period: Shorter than traditional saunas, usually around 10-15 minutes.
• Daily energy usage: Assuming a 1.5kW heater and a total operation time of 1.25 hours, the energy consumption is 1.5kW x 1.25 hours = 1.875 kWh. 

Cost calculation:

Traditional wood burning sauna

These saunas are a specialized type of sauna using wood burning stoves and can also include sauna stones. They provide a much more rustic experience than those using heating elements. Energy efficiency is not applicable in this case because they use wood as fuel, but a cost can still be calculated as follows:

Assuming a 1 to 1.5 hour time to reach optimal temperatures, an average wood burning sauna might consume around 10 - 15kg of firewood per session.

Cost calculation:

• Firewood: Using an average price of £0.10 per kilogram, the cost per session would be 15 kg × £0.10/kg = £1.50.
• Weekly cost: £1.50 × 7 days = £10.50
• Monthly cost: £1.50 × 30.44 days ≈ £45.66

Factors that influence power consumption

Palmako Anita M - 2.2m x 2.5m

1. Insulation and heat retention

Controlling how much power your sauna uses can largely be achieved through proper insulation and heat retention. Apply these key strategies to regulate how much energy you use:

• Use high quality materials such as mineral wool or fibreglass for insulation. They are known for their heat retention and moisture-proof properties. 
• Place insulation between the wall studs and ceiling joints, ensuring a snug fit and preventing air gaps.
• Use heat tolerant wood like cedar or nordic spruce for interior paneling and floor boards. 
• Install insulation between the subfloor and sauna floorboards, but ensure the materials are water-resistant to prevent water damage. 
• Seal and weather-strip dthe oors and windows in your sauna.
• Ensure sauna ventilation as this prevents overheating, and subsequently how much electricity you will use.
• Use modern energy efficient sauna heaters that decrease your sauna’s wattage. They use programmable timers and precise temperature controls for better energy efficiency. 
• Do regular cleaning of the heater and heated rocks to ensure efficient airflow and heating. 

2. Sauna size and design

The design and size of a sauna significantly impacts how cost effective it is to run. Below is an overview of the different sauna designs - barrel, pod, and square - along with considerations on their dimensions and energy requirements.

Oval sauna

The design features a rounded top and bottom with flat front and back walls, aiding in heat distribution and efficient use of interior space. 

Example calculation:

Assume the oval sauna with a length of 2.44m, a width of 1.83m, and a centre height tapering of 2.13m.

Working on an area of 3.63m2 and a volume of 8.9m3, an electric heater of between 6 - 6.5 kW would be suitable. As mentioned previously the running cost of this sauna would be approximately £68.19 a month. 

Barrel sauna

The cylindrical design promotes natural heat circulation and reduced heating times,  therefore using less energy. When the barrel is constructed using timber this further enhances energy efficiency. 

Example calculation:

Assume a length of 1.83 m and an internal diameter of 2.13 m. The volume calculation would come to 6.5m3. Therefore, a 5kW heater would be sufficient to heat a barrel sauna. The costs of running a barrel sauna would look something like this:

• Energy consumption per session: 5kW per session (1 hour session).
• Energy consumption for 30 days: 5 kWh × 30 = 150 kWh.
• Monthly cost: 150 kWh × £0.34 = £51.00

Square sauna

The rectangular or square shape with flat ceilings result in a larger surface area for heating. However, the costs can be mitigated with proper insulation.

Example calculations:

If you haven’t yet decided what type and design of sauna to purchase, then the exact calculation of energy costs could be the deciding factor. It is advisable to get expert help from sauna manufacturers if this is an important consideration for you. 

Contact an expert 

3. Water usage

While water itself does not directly energy consumption, the increased humidity (up to 60%) can have an impact on heat retention, which in turn can change energy needs. A higher humidity transfers heat more effectively, reducing the length of preheating times and heater power for a session. 

Conversely, with a dry sauna (no sauna stones and steam), the humidity is much lower, remaining between 5-15%. 

Cost calculation of dry vs. steam sauna

Let’s compare a 9kW heater under these two conditions:

1. Dry sauna (80°C, 10% humidity, runs at full power for 1 hour) = £91.80 p/m

2. Steamed sauna (60°C, 50% humidity, running at reduced power for 1 hour)= £53.55 per month.

Summary of costs for running different saunas

In the summary below, you can compare the different types, designs, and additional factors that affect energy consumption for a sauna, bearing in mind that a combination of these elements will change the power usage and, therefore, the monthly cost. 

If you’re looking for budget-friendly options: Choose an infrared sauna or barrel sauna. 

If you’re looking for an authentic option: Choose a wood burning, steam sauna.

If you’re looking for a modern energy efficient design: Choose a 6kW oval or square sauna. 

Conclusion

On examination of the different elements affecting energy consumption, it becomes clear that how much it costs to run a sauna is not a straightforward answer. Costs can vary greatly depending on:

The average cost of a unit of electricity for your region.

• The type of sauna.
• The design and size of the sauna.
• Whether it’s a dry or steam sauna.
• The quality of the insulation you use. 

For this reason, it is recommended you contact the manufacturers of the sauna you want to purchase. They will steer you in the right direction, and give you industry insight into the running costs of a sauna because they likely have many years of experience behind them (that’s best case scenario).

Enjoy your sauna!

References:

1. Traditional saunas vs. Infrared saunas