Holl's Utopia 4: 4 Person Indoor Sauna
One configuration. The stove heater, its stones and the sauna kit are all in the price.
£5,995.00
- 6kW stove, stones and the sauna kit included
- Touchscreen with Bluetooth and MP3 audio
- Full 8mm tempered glass front
- Cabin
- 2,000mm wide, 1,450mm deep and 1,960mm tall, FSC certified hemlock
- Front
- Panoramic 8mm tempered glass, wooden handle inside and stainless steel outside
- Inside
- Abachi benches with headrests, seating four
- Heater
- stove 6kW with volcanic stones
- Controls
- Touchscreen panel inside the cabin, with Bluetooth and MP3 audio
- Lighting
- Seven colour LED chromotherapy and a starry sky ceiling
- Kit
- Wooden bucket and ladle, thermometer and hygrometer, sand timer
- Electrics
- 220 to 240V single phase or 380 to 400V three phase, wired and certified by an electrician
A four seat indoor sauna with a full width glass front, a touchscreen panel and a 6kW heater in the price. Two metres wide and 1.45 deep, so it fits against a wall rather than needing a room to itself.
Delivery & installation
Delivery is included in the price, kerbside to mainland Britain: England, Wales and mainland Scotland. The Scottish Highlands, islands and any address a lorry cannot reach are quoted in writing before dispatch, and if the figure does not suit you, cancel for a full refund. Northern Ireland: write to us before ordering. Nothing is added at checkout.
The cabin arrives flat, as wall panels, roof and the glass front, with the benches, heater and kit boxed separately. On an indoor cabin the question that matters is whether the largest panel turns your stairs, and we confirm that with the distributor for your address before anything is dispatched.
Installation can be arranged where you would rather not build it yourself. Once you place your order we confirm the delivery and installation options for your address, and nothing is dispatched until you are happy with both.
Warranty
Ten years on the wood structure and two years on the electrical components, which are the terms Holl's publish for the Utopia in its 2026 specification sheet.
The UK distributor administers the warranty and raises claims with the maker where needed. The cabin is sold for home use: commercial or very frequent use can affect cover.
Claims come to us. One email, and we deal with the distributor and the maker on your behalf rather than handing you a phone number.
Returns
Until the order is placed with the supplier you can cancel and be refunded in full, with no reason needed.
After that the cabin is on its way from the distributor, and our returns policy sets out exactly where that leaves you. Check the packages against the parts list on the day they arrive and tell us about anything damaged or missing within 48 hours; anything that arrives damaged or faulty is ours to put right either way.
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About this product
The Utopia 4 is a four seat indoor sauna 2,000mm wide, 1,450mm deep and 1,960mm tall, in FSC certified hemlock with abachi benches and headrests. The whole front is panoramic 8mm tempered glass, with a wooden handle inside and stainless steel outside, so the cabin stands against a wall and reads as part of the room.
The heater is a 6kW stove with its stones, and it is in the price with the wooden bucket, ladle, thermometer, hygrometer and sand timer. A touchscreen inside the cabin runs the temperature, the lighting and Bluetooth and MP3 audio, and the ceiling carries a starry sky effect above seven colour LED chromotherapy.
At 6kW it draws about 26 amps at 230V, so it needs a dedicated circuit fitted and certified by an electrician, single or three phase. Holl’s give ten years on the wood and two on the electrical components.
- Secure paymentProcessed by Shopify Payments over an encrypted connection.
- Your details stay privateCard details are never stored on a Tarnfell system.
- Payment on confirmationWe take payment only once your order is confirmed.
- 14 day cancellation rightsCancel within 14 days of delivery, under the Consumer Contracts Regulations 2013.
Who this is actually for.
Every product here is described with the honest opposite beside it: who it suits, and who should be looking at something else. If none of the descriptions below fits you, the right answer is elsewhere in the range, or elsewhere entirely, and we would rather say so.
The whole front is 8mm tempered glass, so the Utopia 4 reads as part of the room rather than a box in the corner of it. At 1.45 metres deep it stands against a wall in a large bathroom, a gym or a garden room, and four people sit on the abachi benches with headrests.
Worth confirmingyou want privacy. A glass front means you are seen from the room, and the room is seen from the bench. The Eccolo 6 has a glass door in a timber front.
A touchscreen inside the cabin runs the temperature, the lights and the audio, with Bluetooth and MP3 playback. The 6kW stove, its stones and the traditional kit are all in the £5,999, so the figure on this page is the figure for a working sauna, before delivery and the electrician.
Worth confirmingyou want the lowest running cost. A 6kW heater and a glass front use more electricity per session than the insulated Eccolo on 4.5kW.
The product that gets used is the one worth recommending, and it is not always the largest one.
The measurements that decide it.
Read this before anything else. An indoor cabin is almost never sent back because it was the wrong product; it is sent back because it would not go up the stairs or stand up in the room.
The floor and the supply are the two to check. A two metre glass front will not sit square on an uneven floor, so it has to be level across its whole width. And 6kW draws about 26 amps at 230V on a dedicated circuit, which an electrician should confirm your board can give before you order. Holl's list the heater for single or three phase supply.
From order to first use.
Here is each stage, and who does what. Delivery is estimated at 10 to 14 working days from order. If you would rather have stock, the date or anything else settled first, email hello@tarnfell.com before you order and we will confirm it in writing.
- Week 0
Order and room check
Ceiling height, floor, access and your consumer unit are agreed before the order is placed with the distributor. There is nothing to configure on the cabin itself.
- Before it arrives
The circuit
An electrician runs a dedicated circuit to where the heater will stand, single or three phase as the heater allows, and leaves it ready to terminate. A room containing a sauna heater is notifiable work.
- Delivery day
To the door, in panels
The cabin arrives flat as hemlock panels, roof and the glass front, with the benches, heater and kit boxed. Check everything against the parts list the day it lands.
- Build day
Two people, working from the manual
Panels up, glass front in, roof on, benches, heater guard and control panel fitted. The distributor's estimate is one to two days for two or three people. If you would rather hand it over, installation is arranged for your address once you have ordered.
- Before first use
The electrician returns
The heater is hung, connected and the circuit tested and certified. You should be handed a certificate. Then the stones go in, loosely, and the first heat cycle burns off the factory smell with the door open.
What owning one actually involves.
The handful of things that decide whether this is still in use in year three.
Temperature, lighting and audio are set on the panel inside the cabin.
An 8mm tempered glass front shows every splash from the bucket. A squeegee after a session keeps it clear.
Hemlock carries far less resin than spruce, so the weeping pitch pockets spruce cabins are known for are not a problem here. Keep it bare: oils and varnishes bake.
An unheated timber room in a house that breathes is where mould starts, and one cycle a month prevents it.
Nothing else inside. Detergents leave a film that bakes on the benches.
The running costs, with the working shown.
The purchase price is public; the running cost rarely is. Ours are published with the assumptions stated, so you can check the arithmetic and change it for your own tariff.
about £1.80
Heat up: 6kW for 45 minutes is 4.5 kWh. Holding: 1 hour at roughly 40% duty is 2.4 kWh. Total 6.9 kWh at 26.11p is about £1.80.
about £187
104 sessions at £1.80.
a few pounds, every few years
Volcanic stones crack with use, are restacked yearly and replaced when they crumble. They are the only consumable part.
Assumptions: electricity at the Ofgem price cap unit rate of 26.11p per kWh, 1 July to 30 September 2026, including VAT. Figures are calculated from the heater's rated output of 6kW, not measured on an installed cabin. 45 minutes to heat up and a 40% holding duty are our working figures for a cabin of about 5.7 cubic metres indoors.
What you have to do, and what the rules require.
Everything you have to do, and how often.
| Job | How often | Who |
|---|---|---|
| Install and certify the circuit 6kW draws about 26A at 230V single phase. Holl's list this heater for 220 to 240V single phase or 380 to 400V three phase. Protective device and cable size are for your electrician to specify from the heater's own instructions. A room containing a sauna heater is notifiable electrical work in England and Wales. | Once, before first use | A qualified electrician |
| Restack and inspect the stones Lift them out, discard any that are cracked or crumbling, and restack loosely so air moves between them. | Yearly | You |
| First heat with the door ajar The distributor advises a first cycle at 60°C for 90 minutes with the door open to cure the timber. | Once | You |
| Heat it even when you are not using it One heating cycle a month if the cabin is out of use. | Monthly when idle | You |
| Air it after use and wipe the glass Door open until the room is dry, and a squeegee on the glass front. | Every session | You |
Where this comes from.
Regulation and guidance, linked so you can read it yourself. None of it is our opinion.
- A room containing a sauna heater is notifiable electrical workApproved Document P, 2013 edition
- A sauna heater must not be protected by a residual current device, while other circuits in the room must beBS 7671 regulation 703.412.5
- Utopia 4 (HL-UTA04B-PK) is 200 × 145 × 196cm, seats four, hemlock with abachi benches, an 8mm tempered glass door, a 6kW stove with stones on 220 to 240V or 380 to 400V, touchscreen with audio, seven colour LED, 10 years on the wood and 2 on the electrical componentsHoll's Utopia 2026 specification sheet, via the UK distributor
- Electricity unit rate of 26.11p per kWh, 1 July to 30 September 2026Ofgem energy price cap
Every figure the makers publish.
- Warranty
- 10 year wood, 2 year electrical warranty
- Lead time
- Estimated 10 to 14 working days from order. We confirm stock and your delivery date in writing when we process your order.
Cabin and heater figures are from Holl's own 2026 specification sheet for the Utopia range, supplied by the UK distributor. Where a figure is ours rather than theirs, it says so.
What arrives, and what does not.
- The cabin as hemlock panels and roof, with the panoramic glass front
- The abachi benches and headrests
- The stove 6kW heater with its volcanic stones
- The touchscreen panel with Bluetooth and MP3 audio, the seven colour LED and the starry sky ceiling
- The sauna kit: wooden bucket and ladle, thermometer and hygrometer, sand timer
- Ten years of the maker's warranty on the wood and two on the electrical components
- The electrical work. A dedicated circuit, run, terminated and certified by an electrician
- Assembly, unless you ask us to arrange it
- Any building work to the room itself, including flooring and ventilation
- Delivery to offshore and remote postcodes, which is quoted before you order
Reasons to buy something else.
A full glass front means the cabin and the room see each other. The Eccolo 6 has a timber front with a glass door.
The heater will not run from a socket. If a dedicated circuit is not possible, an infrared cabin on a lighter supply is the honest alternative.
The Utopia is run from the touchscreen on the cabin, so it is switched on where you use it.
A two metre glass front will not close true on a floor that drops. Level the floor first, or choose a cabin with a timber front.
If any of these apply, say so and we will point you at what does suit you, including when that is a cheaper product or one we do not sell.
What we know, and how we know it.
Where every figure on this page comes from, with the source beside it.
- Dimensions, construction and contents
-
Verified
Size, timber, glass, seating, controls, lighting, kit and warranty are taken from Holl's own 2026 specification sheet for the Utopia range and match the UK distributor's listing.
- Heater output and supply
-
Verified
The 6kW output and the single or three phase supply are Holl's published figures. The 26A current and the 5.7 cubic metre volume are our own arithmetic. The fuse and cable size are the installer's calculation on site.
- Warranty administration
Ten years on the wood and two on the electrical components are the maker's published terms. Claims run through the UK distributor, and you deal only with us. The cabin is sold for home use.
The three closest to it.
Harvia Panorama: 4 to 5 Person Indoor Sauna
From £5,760.00- 4 to 5 people
- 4.5 to 9.2m³
- heater and lighting included
Harvia Family Hybrid Small: Infrared and Traditional Indoor Sauna
£6,396.00- 1.66m × 1.59m
- 3.6kW
- 350W infrared
Harvia Variant View: Glass Front Indoor Sauna
From £4,895.00- Six sizes
- 2.02m external height
- spruce walls, aspen benches
- heater and accessory kit included
Weighing this against another sauna? Let us do the homework.
Choosing between two saunas takes evenings of research, so let us carry it. Name the other one you are considering and we will send a straight comparison, including where the other one wins.