The short answer
Running cost depends on the heater rating, how long you run it and your electricity tariff. Assuming a UK rate of about 27p per kWh, a small infrared session works out at roughly £0.40–£0.50, a mid-size traditional electric session (around a 4.5kW heater for about 90 minutes) roughly £0.75–£0.85, and a larger 6–8kW traditional session about £1.35–£1.65. For most homes running two to three sessions a week, that adds up to roughly £8–£20 a month in extra electricity. The biggest levers are the heater rating, how long you heat and use the cabin, and the unit rate you actually pay — so a time-of-use tariff or solar can move the figure.
A sauna's running cost is simply its heater rating in kilowatts multiplied by the hours you run it and your electricity unit rate. The figures below assume about 27p per kWh — adjust them up or down for your own tariff.
Typical per-session cost (at ~27p/kWh)
- Small infrared~£0.40–£0.50
- Traditional ~4.5kW (90 min)~£0.75–£0.85
- Traditional 6–8kW~£1.35–£1.65
- 2–3 sessions a week~£8–£20 / month
- Assumed unit rate~27p / kWh
How the running cost is worked out
The sum is straightforward: heater kW × hours run × unit rate. A 1.5kW infrared cabin run for around 45 minutes uses roughly 1.1 kWh, which at 27p is about 30–50p once you include warm-up. A 4.5kW traditional heater needs longer to bring the cabin up to temperature and hold it, so a 90-minute session sits nearer 75–85p, and a 6–8kW heater for a similar session lands around £1.35–£1.65. Because the rate matters as much as the heater, the same sauna costs noticeably less to run on a cheaper overnight tariff.
| Heater | Per session | 2–3 / week |
|---|---|---|
| Small infrared (~1.5kW) | ~£0.40–£0.50 | ~£8–£12 / month |
| Traditional ~4.5kW (90 min) | ~£0.75–£0.85 | ~£10–£14 / month |
| Traditional 6–8kW | ~£1.35–£1.65 | ~£14–£20 / month |
Indicative figures assuming an electricity rate of about 27p per kWh. Your cost depends on the heater, session length and your tariff. Source: UK supplier running-cost guides.
How to keep running costs down
- Match the size to your use: a smaller cabin and heater costs less per session, so do not oversize it if you mostly sauna alone.
- Consider infrared for frequent solo use: lower wattage and faster warm-up make it lower in cost per session.
- Insulate well: a well-insulated cabin holds heat and needs less top-up energy.
- Use a cheaper tariff: running on a time-of-use or off-peak rate, or from solar, lowers the unit cost that drives the whole figure.
Want a sauna sized to your running budget?
We'll match you with a vetted sauna supplier or installer who can recommend a heater rating that fits how you'll use it and gives you a realistic running cost for your tariff.
Frequently asked questions
How much does it cost to run a sauna per session?
At an assumed UK rate of about 27p per kWh, a small infrared session is roughly £0.40–£0.50, a mid-size traditional 4.5kW session about £0.75–£0.85, and a larger 6–8kW session about £1.35–£1.65. Your cost depends on the heater, how long you run it and your tariff.
Is an infrared sauna cheaper to run than a traditional one?
Generally yes per session, because infrared uses a lower-wattage heater and warms up faster, so a typical infrared session works out lower in cost than a larger traditional electric session at the same unit rate.
How much does a sauna add to my monthly electricity bill?
For two to three sessions a week, most home saunas add roughly £8–£20 a month at about 27p per kWh. A larger 6–8kW traditional heater used often sits at the top of that range, a small infrared cabin at the bottom.
Sources & further reading
- Heracles Wellness — how much does an infrared sauna cost to run
- Steam & Oak — UK sauna buying guide, heaters & costs
Figures on this page are typical UK ranges drawn from published sources and depend on your specific sauna, home and electricity tariff. Running costs assume about 27p per kWh. They are guidance, not a quotation.