There is a question that arrives in almost every first conversation, usually before the drawings are open: how much is a sauna. It is a fair question and an unanswerable one, in the same way that asking the price of a kitchen is fair and unanswerable. Everything depends on whether we are discussing a unit delivered flat-packed to a garage, or a room built into the fabric of a house and expected to outlive the mortgage.
The distinction matters more in this category than in most, because the market is unusually wide. A cabin can be bought online for the price of a good sofa. A bespoke sauna, engineered into a villa and finished to the standard of the joinery elsewhere in the house, belongs to a different economy altogether: closer to a signature kitchen, a lap pool, or the glazing package on a sea-facing facade. Our published starting points are 22,000 euro for an indoor room, 28,000 euro outdoors and 35,000 euro for a fully bespoke commission. They are starting points precisely because the drivers below move the figure.
A sauna is not an appliance you install. It is a room you build, and rooms are priced like rooms.
Flat numbers persist because they are easy to publish and easy to compare. They are also the reason owners are so often disappointed twice: once when the quoted figure turns out to exclude the builder's work, the power supply and the ventilation, and again two winters later, when the timber has moved, the bench is warm on one side and cool on the other, and the room next door has begun to show condensation at the skirting.
A useful budget is built the other way round, from the room outwards. Seven headings carry almost the entire cost of a bespoke Finnish sauna. Once an owner can see them, comparing two proposals stops being guesswork and becomes an ordinary act of reading.
This is the largest single line in most projects and the one that separates the categories most visibly. Species matters: alder, spruce, red cedar and thermo-modified poplar behave differently under repeated cycles between ambient and 90 degrees. Thermo-treatment stabilises the wood and changes both its colour and its price. Beyond species comes selection, and this is where the money quietly goes: boards graded for grain and knot, machined so that nothing ferrous meets skin, benches built as furniture rather than as decking, radiused edges, backrests, and a floating bench structure that carries a body without a squeak. The cost is not in the cubic metres. It is in selection, machining and the hours of a joiner who will not accept the first board.
Output is matched to the volume of the room, its glazing and the thermal quality of its envelope, not to a bracket in a catalogue. A room that holds 80 to 100 degrees comfortably for three hours is engineered differently from one that reaches temperature once and then struggles. Electric or wood-burning changes the figure sharply: a wood stove brings a flue, clearances, a structural penetration and a hearth detail, and it brings a ritual that many owners will not trade. Controls run from a discreet keypad to full integration into the home system, with scheduling and remote pre-heating. The controller is a design object as much as an electrical one, and it is seen every single day.
The least visible line and the one most often cut. A Finnish sauna needs air changes, supplied low near the heater and extracted diagonally opposite, sized for the volume and for the way the room will actually be used. It also needs a drying cycle after use, or the humidity simply migrates into the adjacent joinery. Mechanical and electrical work covers the dedicated circuit, protective devices, earthing, the position of the board and the isolator, and duct routes reserved through ceilings that are frequently already spoken for. Omitting this line does not save money. It defers it, and the deferred version is more expensive.
Everything that has to happen before the sauna arrives: forming and squaring the cavity, levelling the floor and setting falls, tanking where a wet room adjoins, a gully if the design includes a bucket or a shower, structural provision for a stone wall or a stove, thresholds, and making good afterwards. On a renovation this is the most volatile line of all, because it depends on what appears once the finishes come off. Anyone who prices it precisely before opening the wall is guessing.
Glass changes the room and the budget in the same gesture. A full-height panel facing a garden or the sea turns a cabin into a piece of architecture. It also imposes toughened low-emissivity specification, hardware rated for thousands of heat cycles, a heavier structural frame and a heat-load calculation that frequently pushes the heater up a size. Frameless glazing costs several times what a solid wall costs. It is usually worth it. It should be a decision, not a discovery.
Warm, dimmable, circadian and entirely concealed. Fittings must be rated for the temperature and humidity they will live in, drivers must sit outside the hot zone, and scenes must be programmed rather than left at full output. Lighting is modest in absolute terms and decisive in effect: it is the difference between a room that reads as equipment and a room that reads as architecture. It is also the first thing a guest notices and the last thing most quotations mention.
The final five per cent that disappears from cheap proposals. The heat-up curve is measured and adjusted, ventilation is balanced, controls are programmed to the household, the timber is conditioned through its first cycles, safety checks are documented, and the owner and house staff are trained. A signed technical handover goes into the property file. Our programme runs 8 to 14 weeks from signature, and commissioning is not the moment the van leaves. It is the moment the room behaves.
Published starting points, before the drivers above are applied. Every commission is priced after a technical visit.
A room built into the fabric of the house: cavity, joinery, heater, controls, ventilation, lighting and commissioning, coordinated with the works.
Garden, terrace and rooftop projects. The envelope, base, weather detailing and buried supply are additional to the room itself.
Authorial commissions: structural glazing, stone, wood-burning stoves, integrated controls and a geometry drawn for one house only.
Most of the projects we are asked about sit in Marbella, Mallorca and Ibiza, and each adds its own line to the budget. Coastal air is aggressive on fixings, hinges and anything ferrous, which pushes hardware specification upward and makes the cheap version fail visibly within a couple of seasons. Island logistics add freight and, more consequentially, add risk to the programme: a missed sailing is not a missed morning. Access matters more than owners expect, because a bench blank that cannot reach a basement stair has to be built in pieces, and pieces cost more than blanks.
There is also the question of occupancy. Many of these houses are used in bursts. That changes ventilation strategy, argues for remote control and monitoring, and makes the case for materials that tolerate long periods of closure without complaint. None of it is exotic. All of it is cheaper to specify at the beginning.
The wider works matter too. A sauna specified while the building is open costs materially less than the same sauna retrofitted afterwards, for reasons we set out in our piece on integrating wellness into an architectural project. If a cold plunge is part of the ambition, it should be decided at the same time rather than added later: our architectural ice baths run from 12,000 to 24,000 euro and share drainage, power and structure with the sauna, which is precisely why the two are best drawn together.
The failure is rarely dramatic. An undersized heater runs flat out and never quite holds the room. Ventilation was left to a bathroom extract, so the air feels heavy and the humidity finds the wardrobe next door. Softwood benches begin to bleed resin. Door hardware that was never rated for heat cycles starts to bind. A shared electrical circuit trips whenever the oven is on. Nothing breaks. The family simply stops going in, and by the second winter the most expensive square metres in the house have become storage.
Set against that, the arithmetic of doing it properly is unremarkable. A well-built sauna is a fixed part of the house, on the same footing as the kitchen or the pool, and it is used on the ordinary Tuesday evenings that no brochure photographs: the ones where sleep improves, the shoulders release, and the day is genuinely put down. That is the return, and it is not measured in resale percentages. It is measured in how often the door opens.
Ask for the seven headings separately. Ask what is excluded, in writing. Ask who owns the interfaces with the builder, the electrician and the ventilation contractor, because the gap between trades is where budgets are quietly destroyed. Ask what commissioning includes and what the handover document contains. Ask what happens in year three. A supplier who can answer those five questions calmly is usually the one whose figure will hold.
Owners commissioning for their own house will find the process described in more detail on our page for private clients. The dossier goes further: it sets the drivers above against real project configurations, so that a number stops being an abstraction and becomes something you can plan around.
We take a limited number of projects per year. Request the technical dossier and we will contact you within 24 business hours to arrange a first conversation, without commitment.
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