Wood-fired vs electric sauna.
Wood-fired vs electric sauna: how they differ, what they cost and which to choose.
Wood-fired and electric saunas reach the same 70–90°C. The difference is the fire: a wood stove usually holds far more stone, needs no mains power and fills the room with crackle and scent; an electric heater is cleaner, quieter and runs itself. Here’s how they compare on heat, time and cost, with real electricity prices for Ireland and the UK.
Updated · 6 min read
Wood-fired vs electric sauna at a glance
Both are traditional saunas: a stove heats a pile of stones and the air, and you throw water on the stones for steam. The difference is the fire. A wood stove usually holds far more stone and gives the room a crackle, a smell and a rhythm that many people love. An electric heater is cleaner, quieter, easier to control and needs nobody to tend it.
| Wood-fired | Electric | |
|---|---|---|
| Heat source | A fire of logs in a firebox under the stones | Electric elements among the stones |
| Stones | Often 100–260 kg in larger stoves1 | About 20 kg in a typical 9 kW heater2 |
| Temperature | Usually 70–90°C | Usually 70–90°C |
| Control | By feeding the fire and opening the air vents | A thermostat and timer, often an app |
| Running cost | Firewood, plus someone’s time | Electricity: about 7–13 kWh for a two-hour session |
| Supply needed | A flue and chimney, and safe distances to walls | A dedicated electrical circuit |
| Where you’ll find one | Many seaside, lakeside and mobile saunas | Spas, gyms, hotels, homes and some community saunas |
Typical sauna temperatures are 70–90°C either way, according to Visit Finland.3 You can’t tell the heat source from a thermometer.
Does wood-fired heat feel different?
Many bathers say a wood-fired sauna has softer, rounder heat, and sellers of wood stoves make the same claim. Harvia says its 200 kg stove gives “soft löyly, session after session”.4 There are no controlled studies, so treat this as experience rather than fact. What is measurable is the stone. Wood stoves often hold several times more stone than an electric heater, so they store more heat and turn more water into steam before the stones cool. The Finnish Sauna Society says stone mass ranges from a few dozen kilos to several hundred, and some large public heaters hold about a tonne.5
Large electric heaters with lots of stone exist too, and they behave more like a wood stove. They use more energy because there’s more stone to heat.6 The sound and smell of a fire, and the light from a glass stove door, are the part an electric heater can’t copy.
The smoke sauna: the original
The oldest kind of Finnish sauna has no chimney at all. In a smoke sauna (savusauna), a fire burns under a huge pile of stones for hours, the smoke fills the room and leaves through a hatch, and when the stones are glowing with stored heat the fire is let die, the smoke is aired out and the benches washed.7,8 It can take around six hours to heat, sometimes more than seven, and you wait at least an hour after the fire goes out before bathing.7,8 The Finnish Sauna Society recommends bathing at a gentler 60–80°C.7 Lighting and feeding the fire releases carbon monoxide, which is why the room is cleared before anyone goes in.7
How long each takes to heat
An electric heater runs at full power for the first 30–40 minutes, and Harvia’s worked example heats for about an hour before bathing.9 A wood stove takes about as long in practice, depending on the stove, the size of the room and the wood, and someone has to keep feeding it. Smoke saunas take most of a day.8 Heaters that store heat in big stone masses can take a few hours, whatever the fuel.5
Running costs
Harvia, a heater maker, says a 6 kW electric heater uses about 7–9 kWh over two hours in a well-insulated room, and an 8 kW heater 9–13 kWh.9
| Heater | Energy | Ireland, about €0.39/kWh | UK price cap, 26.32p/kWh |
|---|---|---|---|
| 6 kW | 7–9 kWh | €2.70–€3.50 | £1.85–£2.35 |
| 8 kW | 9–13 kWh | €3.50–€5.00 | £2.35–£3.40 |
Irish prices are Eurostat’s average for households in the first half of 2026, €0.3871 per kWh with taxes.10 UK prices are the Ofgem cap for direct debit customers from 1 October to 31 December 2026, 26.32p per kWh, plus a standing charge.11 Businesses pay their own tariffs, so a commercial sauna’s cost will differ.
Firewood is harder to price per session, because use depends on the stove, the room, the weather and how hot you like it. Kiln-dried beech sells for around €280–€320 for a 400 kg crate in Ireland.12 We found no reliable figure for kilos per session, so we haven’t guessed one.
Wood, smoke and the law
Burning damp wood makes more smoke. In Ireland, logs sold in units under 2 m³ must have a moisture content under 25%, under the Solid Fuel Regulations that took effect in October 2022, with a tighter limit of under 20% planned.13 In England, the domestic solid fuel rules say you should not burn wood until its moisture content is 20% or less.14 Buy kiln-dried or properly seasoned logs, and you get more heat and less smoke for your neighbours.
The Finnish Sauna Society’s fire safety advice: never leave a stove unattended while it heats, have flues swept regularly, and remember ash can stay hot for up to 24 hours.15 Fit a carbon monoxide alarm in any building with a wood stove.
Wood-fired saunas in Ireland and the UK
Ireland had at least 242 independent saunas by late 2025, about nine in ten opened since 2020, and some are on trailers.16 Many seaside saunas use wood: of 19 listed by Image magazine in 2025, five describe themselves as wood-fired and none as electric; the rest don’t say.17 A wood stove needs no mains power, which is one reason it suits a beach, a pier or a field. Electric heaters are more common indoors, in spas, gyms and hotels.
Which should you choose?
- As a guest, choose by place and feel. If you want the fire, the smell of wood and a sea swim between rounds, look for a wood-fired seaside sauna. If you want a reliable, steady heat after work, an electric sauna is just as hot.
- Building one at home, electric is simpler: a thermostat, a timer and no chimney, but you need a dedicated circuit and an electrician. Wood needs a flue, safe clearances and dry wood, but works off-grid.
- Running a sauna business, wood suits a mobile or seaside site without power and gives a strong story; electric saves staff time between sessions and is easier to keep at an exact temperature.
Whichever heat you choose, the routine is the same: a few rounds of heat, cooling off and rest. Our guide to using a sauna covers it.
How we wrote this page
We read the studies, reviews and official guidance linked below and checked every number on this page against its source. Where a figure we found only appeared in news coverage or on a seller’s site, we left it out or said so. Stove and heater figures come from the manufacturer, Harvia, and the Finnish Sauna Society; claims about the feel of the heat are labelled as claims. Running costs are our arithmetic from Harvia’s energy figures and published electricity prices. We last checked the sources on 21 October 2026. Spotted something wrong? Email us.
Olladay makes booking software for saunas, so we’d like more people to use them. That’s a reason to be careful with claims, not to oversell them.
References
- Harvia. Legend 240 SL wood-burning sauna heater, product page (manufacturer). www.harvia.com/en/products/WK240LDSL/legend-240-sl-black
- Harvia. Vega BC90 9 kW electric sauna heater, product page (manufacturer). www.harvia.com/en/products/HCB900400S/vega-bc90-90-kw-steel
- Visit Finland. 10 sauna tips for beginners. www.visitfinland.com/en/articles/10-sauna-tips-for-beginners/
- Harvia. Legend 240 Vision wood-burning sauna heater, product page (manufacturer). www.harvia.com/en/products/WKLE20GM/legend-240-vision-black
- Finnish Sauna Society. Sauna heater. sauna.fi/en/sauna-knowledge/sauna-heater/
- Harvia. How to choose an electric sauna heater for energy efficiency (manufacturer). www.harvia.com/en/ideas-and-trends/inspiration/how-to-choose-an-electric-sauna-heater-for-energy-efficiency
- Finnish Sauna Society. A good smoke sauna. sauna.fi/en/sauna-knowledge/a-good-smoke-sauna/
- Sinclair J. Remote Finnish smoke sauna draws visitors from near and far. This is Finland. July 2026. finland.fi/?p=123409
- Harvia. The cost of heating a sauna is less than you think (manufacturer). www.harvia.com/en/ideas-and-trends/sustainability-and-safety/the-cost-of-heating-a-sauna-is-less-than-you-think
- Eurostat. Electricity prices for household consumers, bi-annual data (nrg_pc_204), Ireland, 2,500–4,999 kWh a year, all taxes included. ec.europa.eu/eurostat/databrowser/view/nrg_pc_204/default/table
- Ofgem. Changes to energy price cap between 1 October and 31 December 2026. www.ofgem.gov.uk/news/changes-energy-price-cap-between-1-october-and-31-december-2026
- TJ O’Mahony. Kiln dried beech firewood log crate, 400 kg (retailer). tjomahony.ie/kiln-dried-beech-firewood-log-crate-400kg-88beech400.html
- South Dublin County Council. Solid fuel regulations. sdcc.ie/en/services/environment/environmental-health/air-and-noise/solid-fuel/
- The Air Quality (Domestic Solid Fuels Standards) (England) Regulations 2020, Schedule 2. www.legislation.gov.uk/uksi/2020/1095/schedule/2/made
- Finnish Sauna Society. Fire safety in the sauna. sauna.fi/en/sauna-knowledge/fire-safety-in-the-sauna/
- King B. The sauna boom in Ireland. Spas.ie. 17 November 2025. spas.ie/blog/the-sauna-boom-in-ireland
- Seaside saunas to visit all around Ireland. Image. 6 August 2025. www.image.ie/living/seaside-saunas-to-visit-all-around-ireland-964041
Questions
Is a wood-fired sauna better than electric?
Neither is hotter: both usually run at 70–90°C. Many people prefer the softer feel, smell and sound of a wood-fired sauna, and wood stoves often hold far more stone, which stores more heat for steam. Electric is easier to control and needs nobody to tend the fire. The feel of the heat has not been studied.
How long does a wood-fired sauna take to heat up?
Usually around an hour, depending on the stove, the room and the wood. A traditional smoke sauna takes around six hours, sometimes more than seven.
How much does it cost to run an electric sauna?
A 6 kW heater uses about 7–9 kWh over a two-hour session, according to the maker Harvia. That is about €2.70–€3.50 at average Irish household prices in 2026, or £1.85–£2.35 at the UK price cap from October 2026.
What is a smoke sauna?
The oldest kind of Finnish sauna, with no chimney. A fire heats a large pile of stones for hours while smoke fills the room. When the stones are hot, the fire is let die, the smoke is aired out and people bathe in the stored heat.
Can you put water on the stones of an electric sauna?
Yes, on a standard electric sauna heater designed for it. Use a ladle, a little at a time, and never pour water on an infrared panel.
What wood is best for a sauna stove?
Dry hardwood such as kiln-dried birch, ash or beech burns hot with little smoke. Wood should be under 20–25% moisture; in Ireland, logs sold in small amounts must be under 25%, and in England the advice is 20% or less.