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

One of the most common questions when buying a sauna is also one of the most practical: how much will it actually cost to run?

The answer is usually less dramatic than you might expect.

For a typical 3 to 4-person electric sauna with a 6kW heater, Harvia's published figures indicate around 7–9kWh of electricity for a two-hour session, including the initial heat-up period. At the electricity price cap rate in force from 1 October to 31 December 2026, 26.32p per kWh, that works out at roughly £1.84–£2.37 per session.

Used three times a week, that is approximately £287–£370 per year.

But there is more to sauna running costs than the heater's headline kW rating. Cabin size, insulation, glazing, temperature, ventilation and how often you use the sauna all make a difference.

How much electricity does a sauna use per session?

It is easy to look at a 6kW heater and assume that it consumes 6kWh every hour.

That is not normally how an electric sauna operates.

The heater may draw its full rated power while bringing the sauna up to temperature. Once the target temperature is reached, the thermostat cycles the heating elements on and off rather than running them continuously.

Harvia gives a useful real-world example for a traditional Finnish family sauna with a 6kW heater:

• First hour: approximately 4–5kWh
• Second hour: approximately 3–4kWh
• Total for two hours: approximately 7–9kWh

At 26.32p per kWh, that gives an electricity cost of approximately:

• 7kWh: £1.84
• 9kWh: £2.37

So a useful working figure for a typical two-hour electric sauna session is around £2, although the actual figure will depend on the sauna, heater, conditions and electricity tariff.

These figures come from Harvia's own published energy-consumption guidance and assume a suitably insulated sauna with an appropriately sized heater.

What does a sauna cost to run per year?

Let's use the same example and assume you use the sauna three times a week, with the heater operating for two hours per session.

Harvia estimates annual consumption of approximately 1,092–1,404kWh under those conditions.

At 26.32p per kWh, that works out at approximately:

Usage	Annual electricity use	Approx. annual cost
Lower consumption	1,092kWh	£287
Higher consumption	1,404kWh	£370

That gives a realistic range of roughly £287–£370 per year for this particular usage pattern.

Harvia also notes that more efficient use can bring annual consumption down to around 780kWh. At 26.32p per kWh, that would be approximately £205 per year.

Your actual figure could be higher or lower. A larger sauna, extensive glazing, colder outdoor conditions, a different heater or more frequent use will all affect consumption.

What has the October 2026 price cap change done to the cost?

Energy prices move, so it is worth putting these calculations into context, and the change that took effect on 1 October 2026 is more interesting than its headline suggests.

Ofgem's electricity price cap rate for a typical Direct Debit customer in Great Britain is 26.32p per kWh for 1 October to 31 December 2026, with a standing charge of 54.83p a day. The cap in force to 30 September 2026 was 26.11p per kWh with a standing charge of 57.19p a day.

On the unit rate that is a rise of 0.21p, which adds about a penny to a two-hour session. On that basis the economics of using an electric sauna have not changed at all.

There is a second change behind it, though, and it is the reason Ofgem states that costs for this period cannot be compared directly with previous ones: no VAT is charged on household electricity under the cap between 1 October 2026 and 31 March 2027. The July to September figure of 26.11p included 5 per cent VAT. The October figure of 26.32p includes none.

Working that through, and this is our inference from the two published figures rather than an Ofgem statement: strip the VAT out of 26.11p and the pre-tax rate was about 24.87p, against 26.32p now. The underlying cost of the electricity therefore rose by roughly 5.8 per cent, while the price you actually pay rose by about 0.8 per cent. The VAT removal absorbed the difference for this cap period.

Two practical consequences for a buyer. The session and annual figures above are what you will pay this winter, so plan on them. And when the VAT holiday ends on 31 March 2027, the headline rate will move by more than the underlying wholesale picture alone would explain, so a sauna budget built on this winter's numbers should expect a step up next spring rather than treat it as a surprise.

The wider point stands either way: your usage pattern and the sauna itself have a much bigger influence on the total annual cost than the unit rate does.

Why does heater size matter?

Heater size should not be considered in isolation.

A sauna heater needs to be correctly matched to the volume and construction of the sauna. Harvia's guidance uses approximately 1kW of heater power per cubic metre as a starting point.

There is an important qualification when a sauna contains a lot of glass or other poorly insulated surfaces. Harvia's sizing guidance states that each square metre of glass, stone or similar uninsulated surface can add a heating requirement equivalent to approximately 1.2m³ of sauna volume.

This is one reason why two saunas with similar internal dimensions can require different heaters.

For example, a compact, well-insulated timber sauna with limited glazing may need considerably less heating capacity than a similar-sized cabin with a large glass frontage.

That does not mean the larger heater will necessarily use dramatically more electricity every time you use the sauna. What matters is the combination of heater sizing, heat loss, warm-up time, insulation, glazing and thermostat cycling.

What does heater size mean for your electrics?

Heater power also has implications for the electrical installation.

As a simple example, a 6kW load at 230V is approximately 26 amps. However, that does not mean every 6kW sauna heater should simply be connected to a standard domestic circuit.

Sauna heaters are normally installed as dedicated electrical loads, and the exact supply requirements depend on the particular heater, its configuration and the manufacturer's installation instructions.

Before buying, check the electrical requirements for the specific heater and have the installation assessed by a suitably qualified electrician.

Getting this right at the planning stage is much easier than discovering later that your intended sauna requires additional electrical work.

How can you reduce sauna running costs?

The biggest opportunity is not necessarily buying the heater with the lowest kW rating. It is choosing and operating the complete sauna correctly.

1. Choose the correct heater size

An undersized heater may struggle to bring the sauna to temperature efficiently, particularly where there is substantial glazing or heat loss.

Equally, heater selection should be based on the actual sauna volume and construction rather than simply choosing the biggest heater available.

2. Avoid unnecessary pre-heating

If the sauna is ready before you need it, you are paying to maintain a temperature while nobody is using it.

Plan the warm-up period around when you actually intend to use the sauna.

3. Keep the sauna well insulated

Insulation helps reduce the amount of heat escaping through the walls and roof. This becomes particularly important in colder weather and in larger cabins.

4. Think carefully about glazing

Large areas of glass can make a sauna look fantastic, but they also affect heat loss and therefore heater sizing.

If you are comparing two designs, look beyond the floor area and consider the amount of glass as part of the overall heating equation.

5. Use the sauna at a sensible temperature

You do not necessarily need to run a sauna at its highest possible temperature.

Harvia notes that a lower sauna temperature can still produce a satisfying steam experience, depending on the heater and how water is used on the stones.

6. Maintain the heater

Harvia recommends checking and restacking the sauna stones at least annually. Proper stone maintenance helps maintain airflow and heat transfer through the heater.

For a wood-fired sauna, regular chimney sweeping and appliance maintenance are also important parts of ownership. What else the cabin itself asks of you each year, and what it costs to skip, is set out in our guide to how much maintenance an outdoor sauna needs.

What about wood-fired saunas?

Wood-fired saunas are different because the main energy cost is the fuel rather than electricity.

That makes a simple electric-versus-wood price comparison difficult. The cost of firewood varies by location, supplier, moisture content and how efficiently the stove is operated.

There are also additional considerations around storage, lighting the stove, ventilation, chimney maintenance and local regulations.

In England, for example, wood sold for domestic use in quantities under 2m³ must meet the government's Ready to Burn requirements, including a moisture content of no more than 20%. Smoke control area restrictions can also apply.

For wood-fired saunas, chimney maintenance is part of the ongoing cost of ownership. HETAS recommends having a chimney used to burn wood swept twice a year.

If you are deciding between the two, our guide to wood-fired and electric saunas looks at the wider differences rather than focusing only on fuel cost.

What does this mean when choosing a sauna?

Running cost is worth considering, but it should not be the only number you look at.

A sauna that costs slightly less to run but takes longer to heat, has more complicated electrical requirements or does not suit the way you intend to use it may not be the right choice.

Instead, look at the complete system:

• Sauna volume
• Heater power
• Insulation
• Amount of glazing
• Ventilation
• Warm-up time
• Expected frequency of use
• Electrical requirements
• Ongoing maintenance
• Purchase price

This is particularly important when comparing saunas at very different price points. The cheapest sauna to buy is not necessarily the cheapest to own, and the most expensive sauna is not automatically the most expensive to run.

If you are comparing models, start with the specifications and work backwards from how you actually intend to use the sauna. You can browse the Tarnfell sauna collection once you have a clearer idea of the size and specification that suits your space.

Whether you site a traditional sauna indoors or in the garden is a decision in its own right, and indoors takes the outside weather off the list of things above that push consumption up. Grouped by the number of people each maker states, the traditional indoor range looks like this:

• Two people: the France Sauna Zen 2.
• Three: the France Sauna Zen 3.
• Three to four, built for a corner: the France Sauna Zen 3C.
• Four: the France Sauna Zen 4 and the Holl's Utopia 4.
• Four to five: the Harvia Panorama.
• Six: the Holl's Eccolo 6.
• Glass front, offered in several sizes: the Harvia Variant View.

A large glass front brings the glazing point above straight into play, so on a glass fronted cabin check the heater the maker has fitted against the room it has to heat.

The short version

For a typical 3–4-person electric sauna with a 6kW heater, a useful starting point is:

• 7–9kWh for a two-hour session
• £1.84–£2.37 per session at 26.32p/kWh, the cap for 1 October to 31 December 2026
• £287–£370 per year when used three times a week
• Potentially around £205 per year with lower annual consumption of approximately 780kWh

The exact figure will depend on your sauna, heater, installation, electricity tariff, outdoor conditions and how you use it.

That is why the headline heater rating is only part of the story. When choosing a sauna, consider the whole heating system, the cabin construction and the way you expect to use it.

And if you are also considering a cold plunge, you can compare the ongoing costs in our guide to what a cold plunge costs to run in the UK.

Sources

• Harvia, energy consumption and sauna bathing guidance
• Harvia, sauna heater sizing guidance
• Ofgem, electricity price cap unit rates and standing charges. The 1 October to 31 December 2026 figures of 26.32p per kWh and a 54.83p daily standing charge, and the removal of VAT on electricity from 1 October 2026 to 31 March 2027, were read on 1 October 2026. The 1 July to 30 September 2026 figures of 26.11p and 57.19p included 5 per cent VAT.
• GOV.UK, Ready to Burn wood requirements in England
• HETAS, chimney sweeping and appliance maintenance guidance