Sauna Running Cost Calculator UK
Estimate the cost to run an electric sauna heater by session, week, month and year.
Results are estimates. Actual costs vary with insulation, outdoor temperature, desired sauna temperature and how often the door is opened.Your sauna details
Enter the pence per kWh rate from your energy bill. The UK price cap rate is around 24 to 28p per kWh for most households.
Please enter a value between 1 and 100.
Typical home saunas use 6 to 10.5 kW. Larger rooms and outdoor saunas may need more.
Please enter a value between 2 and 18.
Including warm up time. Typical sessions last 1 to 2 hours.
Please enter a value between 0.25 and 6.
How many times per week you use the sauna.
Please enter a value between 1 and 14.
Standard usage with no smart scheduling or standby heating.
How many hours per day the sauna maintains a low keep warm temperature.
Please enter a value between 0 and 24.
The percentage of full heater power used during standby. Typically 20 to 40%.
Please enter a value between 10 and 60.
Estimated running costs
Get a personalised running cost estimate
Share a few details about your sauna and we will send you a tailored heater recommendation and a realistic running cost range based on your setup and location.
Compare heater sizes
Compare up to 4 heater sizes side by side using your current unit rate and usage settings.
| Heater (kW) | Per session | Per week | Per month | Per year |
|---|
Explore Sauna Types and Compare Running Costs
Different sauna types use different heater sizes, which directly affects how much electricity they consume per session. Use the calculator above to model your specific setup, then explore the sauna types below to understand how heater size and running costs relate to each category.
6 to 12 kW
Traditional Finnish Saunas
Traditional Finnish saunas heat to 80 to 100°C, with heaters ranging from 6 kW for compact indoor rooms up to 12 kW for larger cabins. The heater runs at full power for the first 30 to 45 minutes of each session. Enter your heater size into the calculator above for an accurate cost per session.
Browse traditional Finnish saunas →
3 to 6 kW
Hybrid Infrared Saunas
Hybrid infrared saunas combine convection heating with infrared panels, reducing warm up time and overall energy use compared to a purely convective sauna. Heater sizes tend to be lower, often 3 to 6 kW, making them a cost effective option for regular use.
Browse hybrid infrared saunas →
6 to 9 kW
Barrel Saunas
Barrel saunas have a curved interior that reduces the volume of air to be heated, improving efficiency compared to a rectangular cabin of the same floor area. A typical barrel sauna for 2 to 4 people uses a 6 to 9 kW heater. Outdoor models may need slightly more power in colder months.
View the Valour barrel sauna →Popular Outdoor Sauna Examples and Typical Heater Sizes
Outdoor saunas are subject to greater heat loss than indoor installations, particularly in winter. The examples below show typical heater sizes for popular outdoor models. Enter these figures into the calculator above to see realistic running cost estimates for your location and usage pattern.
8 to 10.5 kW
The Sanctuary — 5 Person Outdoor Sauna
A 4 to 5 person outdoor cabin requires a heater in the 8 to 10.5 kW range to reach temperature reliably in all seasons. In colder months, heat loss through the walls and roof increases the effective running time. Good insulation and a well fitted door significantly reduce this effect.
View The Sanctuary →
10.5 to 12 kW
The Hideout — 6 Person Outdoor Sauna
A 6 person outdoor Finnish sauna typically requires a 10.5 to 12 kW heater. At 28p per kWh, a 10.5 kW heater running for 1.5 hours costs approximately £4.41 per session. Outdoor conditions in the UK can add 10 to 20% to effective energy use in winter months.
View The Hideout →
6 to 9 kW
The Heatwave — 4 Person Sauna
A 4 person sauna in a well insulated indoor or garden room setting typically uses a 6 to 9 kW heater. Indoor installations benefit from ambient warmth and better insulation. At 28p per kWh, a 9 kW heater for a 1.5 hour session costs approximately £3.78.
View The Heatwave →How Sauna Running Costs Are Calculated
The energy a sauna consumes in a session is determined by the heater size in kilowatts multiplied by the number of hours the heater is running. A 9 kW heater running for 1.5 hours uses 13.5 kWh of electricity per session.
Your electricity unit rate, expressed in pence per kilowatt hour, converts that energy figure into a cost. At 28p per kWh, a 13.5 kWh session costs approximately £3.78. Unit rates vary between suppliers, tariffs and regions, so using your actual bill figure gives the most accurate result.
Weekly, monthly and yearly costs are calculated by multiplying the per session cost by the number of sessions per week, then scaling up. Monthly figures use 52 weeks divided by 12 to give a consistent average rather than assuming every month has exactly four weeks.
Smart scheduling reduces session energy by 10% by pre heating at the optimal moment and avoiding wasted heat. Keep warm standby adds a continuous low level load based on the standby hours and load percentage you specify, which can significantly increase annual costs if left running for many hours each day.
Example Running Cost Scenarios
The following estimates assume 1.5 hours per session and 4 sessions per week. All figures are estimates only. Your actual costs will vary depending on insulation, outdoor temperature and heater efficiency.
| Heater size | Rate (p/kWh) | Per session | Per week | Per month | Per year |
|---|---|---|---|---|---|
| 6 kW | 20p | £1.80 | £7.20 | £31.20 | £374.40 |
| 6 kW | 28p | £2.52 | £10.08 | £43.68 | £524.16 |
| 6 kW | 35p | £3.15 | £12.60 | £54.60 | £655.20 |
| 8 kW | 20p | £2.40 | £9.60 | £41.60 | £499.20 |
| 8 kW | 28p | £3.36 | £13.44 | £58.24 | £698.88 |
| 9 kW | 20p | £2.70 | £10.80 | £46.80 | £561.60 |
| 9 kW | 28p | £3.78 | £15.12 | £65.52 | £786.24 |
| 9 kW | 35p | £4.73 | £18.90 | £81.90 | £982.80 |
| 10.5 kW | 20p | £3.15 | £12.60 | £54.60 | £655.20 |
| 10.5 kW | 28p | £4.41 | £17.64 | £76.44 | £917.28 |
| 10.5 kW | 35p | £5.51 | £22.05 | £95.55 | £1,146.60 |
| 12 kW | 28p | £5.04 | £20.16 | £87.36 | £1,048.32 |
All figures are estimates. Actual costs depend on insulation quality, ambient temperature, door discipline and heater efficiency. Use the calculator above to model your specific setup.
Choose the Right Heater Size
Selecting the correct heater size is one of the most important decisions when buying a sauna. An undersized heater will struggle to reach temperature, particularly in winter, while an oversized heater wastes energy and can overheat a small cabin.
The standard rule is approximately 1 kW per cubic metre of cabin volume for a well insulated indoor sauna. Outdoor saunas, barrel saunas and cabins in exposed locations typically require 20 to 30% more power to compensate for heat loss.
Other factors that influence heater sizing include the desired temperature, the number of users, the frequency of door openings, the type of wall construction and the level of insulation. Glass walls and doors also increase heat loss and may require a larger heater.
If you are unsure which heater size is right for your cabin, use the comparison tool above to model costs across multiple sizes, or request a personalised estimate from the Nuovo Luxury team.
Tips to Reduce Sauna Running Costs
- Improve insulation. A well insulated cabin reaches temperature faster and holds heat longer, reducing total heater run time. Check door seals and wall insulation regularly.
- Practise door discipline. Every time the door is opened, warm air escapes and the heater must work harder to recover temperature. Minimise unnecessary door openings during sessions.
- Time your pre heat carefully. Start heating only as long before your session as needed. Most home saunas reach temperature in 30 to 45 minutes. Heating for longer than necessary wastes energy.
- Use smart scheduling. A smart controller or timer can start the sauna at the right moment so it is ready when you arrive without running unnecessarily. This calculator estimates a 10% saving from smart scheduling.
- Choose the correct heater size. An oversized heater for a small cabin is not more efficient. Match the heater kW rating to the cabin volume as recommended by the manufacturer.
- Avoid standby heating. Keeping a sauna warm continuously between sessions is rarely cost effective for home use. Turn the sauna off after each session and reheat when needed.