How Much Does a Sauna Cost to Run? Gas vs Electric vs Wood (2026 UK)
Short answer: less than most people expect, and closer between the three than the marketing suggests. A home sauna in the UK costs roughly £1.50 to £2.50 per session to heat, whichever fuel you choose. The fuel you pick barely moves your energy bill — what it changes is how you install the sauna and how quickly it's hot.
This guide shows the real 2026 numbers, how they're worked out, and where each option actually wins.
The honest headline
You'll see "gas saunas are 40% cheaper to run" claimed online. On UK prices in 2026, that doesn't hold up. Gas, electric and wood-fired running costs all sit in the same £1.50–£2.50 band per session. If you're choosing a sauna to save money on energy, none of them will change your life. If you're choosing on convenience, install cost and where you can put it, the differences are large — and that's the decision that actually matters.
What it costs per session
Worked on a typical 90-minute session (about 20 minutes to heat up, then topped up to temperature) in a 2–6 person outdoor cabin.
| Fuel | Energy used per session | Unit price (2026) | Cost per session |
|---|---|---|---|
| Gas (FinSteam 8.1 kW propane) | ~0.5 kg propane | ~£47 / 13 kg Calor refill (≈ £3.62/kg) | ~£2–£3 |
| Electric (Harvia 6.8–9 kW) | ~6.8–7.5 kWh | 26.11p/kWh (price cap, 1 Jul 2026) | ~£1.75–£2.00 |
| Wood-fired | a few kg kiln-dried hardwood | ~£4–6 per net of logs | ~£2–£4 |
Over a year at three sessions a week (156 sessions), that's roughly £280–£400 gas, £300 electric, £470 wood — close enough that energy cost shouldn't be the deciding factor.
How the gas number is worked out
The FinSteam heater burns about 0.6 kg of propane per hour at full output. A 90-minute session uses roughly 0.5 kg once you account for throttling back after warm-up. A standard 13 kg Calor propane bottle therefore lasts about 25 sessions — call it two months at three sessions a week. Put another way, an 11 kg cylinder runs ≈ 18 hours at continuous full power, and real sessions use less than full power throughout.
At a typical £47 exchange refill, that works out at about £2–£3 a session in real-world use (closer to £2–£2.50 on a 13 kg economy bottle, nearer £3 on a small 6 kg portable). Buy in a larger 47 kg cylinder and the per-kg price drops, nudging the per-session cost down a little further. (Note: your first bottle also carries a one-off Calor Cylinder Refill Agreement of around £70 — that's a setup cost, not a running cost.) For a deeper side-by-side of the two mains-free-vs-mains options, see electric vs gas sauna running costs.
How the electric number is worked out
A 6.8–9 kW electric heater draws full power to heat up (about 30 minutes), then cycles on its thermostat to hold temperature. A 90-minute session works out at roughly 6.8–7.5 kWh. At the 26.11p/kWh July 2026 price cap, that's ~£1.75–£2.00 a session. A 9 kW heater costs a touch more than a 6.8 kW one because it pulls more during warm-up.
How the wood number is worked out
A wood-fired stove burns several kilos of kiln-dried hardwood per session. At current UK log prices that's ~£2–£4 a session — the widest range of the three, because it depends entirely on what you pay for wood and how long you keep the fire going.
So what actually separates them? Install and convenience
If running cost is a wash, the real decision is everything around it:
Electric is the default, but the sticker price hides the install. A 6.8–9 kW heater needs its own dedicated circuit, wired by a qualified electrician and signed off under Part P — typically £800–£1,500, plus the wait to get one booked. No spare circuit, no electric sauna.
Wood-fired needs no electrician, but it needs a chimney through the roof, 30–45 minutes of warm-up while you tend a fire, and smoke and ash to clear after every session. It's also restricted in many UK smoke-control areas.
Gas (FinSteam) connects to a propane bottle outside, like a patio heater — no dedicated circuit, no electrician for portable use, no chimney, and it's sauna-ready in under 20 minutes (typical) on a dial. It works off-grid (a field, a beach, the bottom of a long garden) where electric simply can't reach. A fixed install still needs a Gas Safe registered engineer for the gas connection, but the appliance itself ships ready to run.
The verdict
Don't buy a gas sauna to save on energy — the saving over electric is marginal. Buy it because it's sauna-ready in under 20 minutes (typical), needs no electrician, no chimney and no mains supply, and can go where the other two can't. Buy electric if you've already got the circuit and want set-and-forget. Buy wood if the ritual of tending a fire is the point and you're not in a smoke-control area.
All three cost about the same to run. They feel completely different to live with.
Read next: Gas Sauna Heaters UK: The Complete 2026 Guide.
Frequently asked questions
How much does a sauna cost to run in the UK?
Roughly £1.50–£2.50 per session, whichever fuel you choose. On 2026 UK prices, electric works out at about £1.75–£2.00 a session at the July 2026 price cap, gas at about £2–£3 a session on a propane bottle, and wood at about £2–£4 depending on log prices. Energy cost shouldn't be the deciding factor between them.
How long does a propane bottle last on a gas sauna?
A standard 13 kg Calor propane bottle covers about 25 sessions — roughly two months at three sessions a week. An 11 kg cylinder runs approximately 18 hours at continuous full power, and real sessions use less because you throttle back after warm-up. A larger 47 kg cylinder lowers the per-kg price further.
Is a gas sauna cheaper to run than electric?
Not meaningfully. Gas and electric both land in the same per-session band at current UK prices, so the running-cost saving is marginal either way. The real differences are installation and placement: gas needs no dedicated circuit, no electrician for portable use and no chimney, and works off-grid where electric can't reach.
What installation costs should I budget beyond the heater?
Electric needs a dedicated circuit installed by a qualified electrician and signed off under Part P — typically £800–£1,500. Wood-fired needs a chimney through the roof and regular sweeping. Portable gas needs neither, though a fixed gas installation still requires a Gas Safe registered engineer for the connection, and your first propane bottle carries a one-off cylinder agreement fee.
Prices correct June 2026 and vary by region and supplier: electricity per Ofgem price cap (1 July 2026, direct-debit average, inc. VAT); propane per typical UK Calor 13 kg exchange refill; logs per typical UK kiln-dried hardwood net. Your costs will vary with session length, sauna size, insulation and local prices.
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