Indoor or outdoor sauna: which should you buy?
Every infrared cabin in Tarnfell's range is built for indoors, so for infrared buyers the decision is already made. For a traditional sauna, it comes down to the room or garden you have, the circuit your supply can give, and whether you will walk outside to use it in January.
If you want infrared, buy indoor: every infrared cabin in Tarnfell's range is built to stand inside a house. If you want a traditional sauna with stones and steam, both routes are open, and the decision usually comes down to three things you can check this week: the room or garden you have, the circuit your supply can give, and whether you will walk outside to use it in January. Indoors is cheaper like for like. Outdoors gives you a building of its own, and asks more of the garden and of you.
Do you want infrared or a traditional sauna?
Settle this first, because for one answer it settles the whole question.
On 3 October 2026 the range held ten infrared cabins and two hybrids, and all twelve sit in the indoor collection. None is listed as an outdoor cabin. So a buyer who has chosen infrared has also chosen indoors, and can go straight to the space and supply checks.
A traditional sauna, a heater with stones that you throw water on, is offered both ways: ten indoor traditional and hybrid cabins and seventeen outdoor cabins. If you are not yet sure which kind of heat you want, our guide to choosing between infrared and traditional takes that decision on its own, because it is a different appliance rather than a cheaper version of the same one.
Where can you actually put it?
Indoors and outdoors fail on different measurements, so take the ones that apply to you.
Indoors, the ceiling is the measurement that most often stops a project. The indoor cabins take between about 1.3 and 4.6 square metres of floor and finish between 1.9 and 2.02 metres tall, but they arrive flat and are built in the room. Harvia publish a 2.3 metre ceiling to assemble the Family Hybrid Small in, roughly 300mm above where it finishes. Measure the lowest point of the ceiling and the route in, and our guide to how much space an indoor sauna needs covers the rest.
Outdoors, the ground, the route and the boundary decide it. Every outdoor cabin in the range arrives on one pallet at the kerb or the nearest firm, level spot a pallet truck can reach, and stands on a base that has to be laid before the pallet arrives. The parts then go by hand, and the makers expect two people for the smaller cabins and three to four for the larger ones. Height matters for planning: in England an outbuilding within two metres of a boundary is limited to 2.5 metres, and the outdoor cabins in the range that publish an overall height sit between about 1.9 and 2.26 metres.
The practical difference is that an indoor sauna borrows a room you already have, while an outdoor one needs a patch of garden turned into a site. Neither is hard. They are different jobs.
What supply can your house give it?
Every traditional sauna in the range, indoor or outdoor, runs on its own circuit fitted by an electrician. What changes is the size of that circuit and how far the cable has to travel.
| Indoor traditional and hybrid | Outdoor | Infrared | |
|---|---|---|---|
| Circuit stated on the product pages | 16A to 50A | 20A to 50A | Varies by model; the Holl's Moon 1 plugs into an ordinary 13A socket |
| Smallest circuit, and on which cabin | 16A, France Sauna Zen 2, Zen 3, Holl's Combi 2 and Harvia Panorama Mini | 20A, France Sauna Gaïa Urban | |
| Cable | Runs within the house | Steel wire armoured cable to the garden on a 30mA RCD, as the Holl's Cocoon 130 and Gaïa Bella pages state | Runs within the house |
Two things follow. First, the bottom of the indoor ladder sits lower: three indoor cabins and the smallest Panorama run on 16 amps, and nothing outdoors goes below 20. Second, an outdoor circuit has to cross the garden in armoured cable, so the distance from your consumer unit to the spot you have in mind is part of the price of the outdoor route, even though only an electrician can put a figure on it.
The top of both ladders is the same 50 amps, and the kilowatt rating is not a reliable guide to where a cabin sits on it. Read the circuit on the page of the cabin you are considering, then check your main fuse.
What does each route cost to buy?
Prices below were read from the live store on 19 October 2026. Delivery to mainland Britain is included in every one.
| Seats | Indoor traditional | Outdoor | Difference |
|---|---|---|---|
| Two | France Sauna Zen 2, £1,802 | France Sauna Gaïa Urban, £3,495 | £3,495 − £1,802 = £1,693 |
| Six | Holl's Eccolo 6, £4,695 | France Sauna Gaïa Luna, £5,995 | £5,995 − £4,695 = £1,300 |
Across the whole range, starting prices run from £1,802 to £6,395 for indoor traditional and hybrid cabins, £1,907 to £5,495 for infrared, and £3,495 to £10,995 for outdoor cabins. Several cabins offer larger sizes or specification options that cost more, and with those chosen the dearest in the range is the Harvia Kaski 180 Panorama at £11,150. Like for like, the outdoor cabin costs more, and that is before the base, which indoors you do not need at all.
Here is the fact worth knowing before you choose outdoors on price. The two cheapest outdoor cabins, the Gaïa Urban and the Gaïa Bella, both carry an April to October recommendation from the maker or its distributor. On the Gaïa Urban that holds whatever you do, because no larger Harvia heater is rated for a room its size. On the France Sauna Gaïa Bella, £4,895, Tarnfell supplies the 6kW heater rather than the 4.5kW so that it works in January. If winter evenings are the point, start from the Bella rather than the Urban, and read each page for what it says about winter use.
Will you use it on a wet evening in January?
This is the question that separates the two routes once the measurements allow both, and it cuts in both directions.
An outdoor sauna is a short walk in the dark and the rain, and then a building of its own: somewhere to cool off in the open air between rounds, and a garden that becomes part of the session. For many owners that walk is the appeal rather than the cost. It also asks for some upkeep, because a timber building outdoors is weathered by the year. Harvia, for example, recommend treating the outside of the Kuusi 180 barrel and drying the cabin out by heating it after wet weather. Our guide to how much maintenance an outdoor sauna needs lists the jobs and which ones matter.
An indoor sauna is down the landing. Our reading, rather than a published figure, is that this is its strongest argument: the easier a sauna is to reach, the more often it gets used, and the indoor route removes the weather from both the walk and the heater's work. Harvia name outdoor conditions among the things that change a session's electricity use, and an indoor cabin is never standing in them.
What this means when choosing
Take the decision in this order, and stop at the first step that answers it.
- Infrared? Then indoor, and the infrared guide above is your next read.
- No spare room with the ceiling height, or no garden spot with a base and a route? Then the other one.
- A supply that can only manage 16 amps? That points indoors, at the France Sauna Zen 2 and the other 16A cabins, until an electrician tells you otherwise.
- Both possible? Then decide on how you will use it. If the picture in your head is a garden, cold air and a building of its own, go outdoors and budget from a cabin whose page says it will work in January. If it is a sauna you will use on a Tuesday night without thinking about it, indoors gives you that for less money.
If you are going outside, the outdoor sauna buying guide takes the next five decisions in order: shape, size, heat, base and siting, and our comparison of all seventeen outdoor saunas puts them side by side once those are settled.
Sources
- Cabin dimensions, heights, circuits, cable, delivery terms, people counts, heaters, seasonal recommendations and prices: Tarnfell's own live product pages and collections, read 3 October 2026, with every price re-read on 19 October 2026. Circuit figures for cabins not re-read that day were read on 25 September 2026.
- Harvia, assembly requirement for the Family Hybrid Small and exterior care for the Kuusi 180, as published on Tarnfell's product pages.
- Harvia, FAQ about the energy consumption of sauna bathing: outdoor conditions among the factors affecting a session's electricity use.
- Planning Portal, outbuildings: the 2.5 metre limit within two metres of a boundary (England), re-read 3 October 2026
