Holl's Moon 4: 4 Person Infrared Sauna
One decision, natural or black, and everything else shown is already in the price.
£5,724.00
Delivery from £250
Exact cost confirmed for your postcode before dispatch.
Typically 8 to 10 weeks, depending on availability and the season. Email us for a current date, or we confirm yours when you order.
- 4,620W full spectrum: 4 quartz and 12 carbon emitters
- Ø180 × H196cm round cabin, four seats
- FSC certified hemlock exterior, abachi interior
- WiFi touchscreen control with Bluetooth audio
- Cabin
- A round cabin 1,800mm across and 1,960mm tall, hemlock outside, abachi inside
- Inside
- One curved bench for four, with holders for a phone, a drink, a towel and a magazine
- Heat
- Four quartz full spectrum emitters and twelve carbon panels, 4,620W in total
- Controls
- A touchscreen with WiFi, so it can be started from your phone
- Sound and light
- A Bluetooth speaker in the ceiling, ambient ceiling light and a colour strip under the bench
- Glass
- A curved 8mm toughened glass door with a full length handle
- Electrics
- 220 to 240V, about 20A at full output, hard wired to its own circuit by an electrician
Infrared is not a smaller sauna, it is a different thing: no stones, no steam and no long warm up, and a session that costs pennies. The Moon is the round one, which is not decoration: the curved wall puts the panels behind and beside you rather than in flat corners.
Delivery & installation
Delivery is available across the UK and the charge is confirmed for your postcode in writing before anything is dispatched. Offshore and some remote postcodes cost more, and we tell you the figure before you commit rather than after.
The cabin arrives in sections for assembly indoors. The number of packages and their weights are being confirmed with the distributor and are not published here until they are, because on an indoor cabin the question that matters is whether the largest section turns your stairs, and a guess is no use to anybody.
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
Holl's covers the wood structure for 10 years and the electrical components (emitters, control panel, lighting and audio) for 2 years from delivery, per the Holl's Moon specification sheet dated 02/2026. Claims are handled through Tarnfell with the UK distributor.
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.
About this product
The Moon 4 is a cylinder 1,800mm across and 1,960mm tall, hemlock outside and abachi inside, closed by a curved 8mm toughened glass door. A curved bench follows the wall and seats four. Four quartz full spectrum emitters and twelve carbon panels, 4,620W in total, are placed around the bench, behind it and beneath it, so the warmth reaches everyone from three sides rather than one.
The control panel is a touchscreen with WiFi, which means a session can be set going from a phone before you walk out to it, and there is a Bluetooth speaker in the ceiling beside the lighting. At 4,620W it draws about 20 amps at 230V, so it is wired to a dedicated circuit by an electrician; Holl's supply it without a cable for that reason. It lives indoors.
Natural hemlock or black: same cabin, same heaters, same price. The only decision is which finish suits the room it is going in.
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.
4,620 watts is about 20 amps at 230 volts, which is beyond any plug and socket. Holl's supply the Moon 4 without a cable because it is wired to a dedicated circuit by an electrician, the same way an electric shower is. In England a new circuit is notifiable work under Part P, so the electrician certifies it. If that is already in hand, or easy to add, this is the one cabin in the range that four adults can sit in together.
Worth confirmingyou want a Finnish sauna. This makes no steam, there are no stones and you cannot throw water. It warms you rather than the air, and people who wanted the other thing are always disappointed.
There is no long warm up and a session costs about £1.11, so it gets used on a Tuesday evening rather than saved for the weekend. The touchscreen has WiFi, so the cabin can be switched on from your phone and be warm when you walk in. That is the honest case for infrared: not that it is better, but that it is used more.
Worth confirminga sauna is an occasion for you. If the ritual of stones, water and real heat is the point, a traditional cabin is the point with it, and the 3.5kW Zen 2 is the smallest one in the range that delivers it.
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 height is the one to check. At 1.96 metres the Moon clears a standard 2.4 metre ceiling comfortably, but the curved sections still have to be tipped upright to assemble it, so a room with a sloping ceiling or a low beam needs measuring where the cabin will actually stand, not at the door. At 1.8 metres across, plus the door swing, this wants a room of its own or a large one shared.
From order to first use.
Here is each stage, and who does what. Before you order, email hello@tarnfell.com and we will confirm the current lead time and the delivery cost for your postcode in writing.
- Week 0
Finish and room check
Natural or black, and where it stands. A 1.8 metre circle with a door that swings outward needs more clear floor than its footprint suggests, so we agree the position with you before the order is placed, along with where the electrician will bring the circuit in.
- Before it arrives
A dedicated circuit, run by an electrician
A circuit of its own from the consumer unit to where the cabin will stand, sized for about 20 amps and terminated ready for the cabin's connection. Holl's supply the Moon 4 without a cable, so the electrician provides the final connection. In England this is notifiable work under Part P and comes with a certificate.
- Delivery day
To the door, in sections
Check the packages against the parts list on the day they arrive and tell us about anything damaged or missing straight away. Two people to carry the curved panels through the house; the Moon 4's are the largest in the range.
- Build day
Two people, working from the manual
The curved wall sections, the door and the roof go together with fixings rather than trades, then the bench, the panels and the control are connected, and the electrician makes the final connection to the circuit. If you would rather hand it over, installation is arranged for your address once you have ordered.
- First use
Connect the app and set a time
Join the cabin to your WiFi from the touchscreen, set the temperature and the session length, and give it about fifteen minutes. There are no stones to stack and no water to add.
What owning one actually involves.
The handful of things that decide whether this is still in use in year three.
Four quartz emitters give the full infrared range, the A, B and C bands, and twelve carbon panels around and under the bench fill in the sides. The air never gets as hot as a Finnish room does. Some people love that and some people miss the steam.
Holl's publish the supply as 220 to 240V and state that the cable is not included, which is the maker's way of saying an electrician connects it. At 4,620W it draws about 20 amps, so it gets a dedicated circuit from the consumer unit, certified under Part P in England. Budget for the electrician's visit alongside the cabin.
No stones, no water, no filter, no chemistry. Wipe the bench and the glass down, leave the door open after use so the abachi dries, and that is the whole list.
A spare room, a bathroom with the space, a home gym or a garage that stays dry. It needs no plumbing, no drainage and no ventilation work. It is not built for outdoors.
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 £1.11
4,620W for 55 minutes is 4.2 kWh at 26.11p. That assumes every emitter runs flat out the whole time, which overstates the real figure once they start cycling.
about £173
156 sessions at £1.11. For comparison, the two seat Moon 2 comes to roughly £86 at the same frequency and an 8kW outdoor barrel roughly £570.
none on a schedule
No stones, no filter, no pump and no chemistry. The emitters and carbon panels are the only consumable parts and they are not on a service interval.
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 rated total output of 4,620W published by Holl's, and assume the emitters run continuously, which overstates the real figure once they cycle at temperature. Holl's do not publish a warm up time for the Moon; fifteen minutes is our working figure for an indoor infrared cabin and it says so here rather than being presented as theirs.
What you have to do, and what the rules require.
Everything you have to do, and how often.
| Job | How often | Who |
|---|---|---|
| Have the circuit installed before the cabin arrives Total load is 4,620W, about 20A at 230V, and Holl's supply no cable. An electrician runs a dedicated circuit from the consumer unit and makes the final connection once the cabin is built. Notifiable under Part P in England. | Once, before first use | An electrician |
| Wipe the bench and the glass A damp cloth and warm water. Nothing film forming on the abachi. | Monthly, or after heavy use | You |
| Leave the door open after use There is no steam, but there is perspiration. Airing it keeps the timber clean and dry. | Every session | You |
| Set a session length on the touchscreen The control has a timer built in. Use it rather than relying on remembering, especially if the cabin is started from a phone. | Once, then as you like | You |
Where this comes from.
Regulation and guidance, linked so you can read it yourself. None of it is our opinion.
- Moon 4 is Ø180 × 196cm, seats four, 4,620W from four quartz and twelve carbon emitters, abachi interior, 8mm toughened glass door, 220 to 240V supply with the cable not included, ten year wood and two year electrical warrantyHoll's Moon specification sheet, edition 02/2026
- Exterior in FSC certified hemlock; touchscreen control with WiFi; Bluetooth audio; ceiling ambient light and LED strip under the benchHoll's Moon specification sheet, edition 02/2026
- Electricity unit rate of 26.11p per kWh, 1 July to 30 September 2026Ofgem energy price cap
- Installing a new circuit is notifiable electrical work in a dwelling in EnglandApproved Document P, Building Regulations 2010
Every figure the makers publish.
- Warranty
- 10 year wood, 2 year electrical warranty
Figures are from Holl's own specification sheet for the Moon range, edition 02/2026, and the UK distributor's listing. Where a figure is ours rather than theirs, it says so.
What arrives, and what does not.
- The round cabin in hemlock, natural or black, with the abachi interior and the curved bench for four
- The curved 8mm toughened glass door with its full length handle
- Four quartz full spectrum emitters and twelve carbon panels, 4,620W in total
- The touchscreen control with WiFi, the Bluetooth speaker, the ceiling light and the colour strip under the bench
- The phone, drink, towel and magazine holders
- Ten years of Holl's warranty on the wood and two on the electrical components
- Assembly, unless you ask us to arrange it
- Delivery. It is quoted for your postcode and confirmed in writing before dispatch
- The dedicated circuit and the electrician's connection. Holl's supply no cable
Reasons to buy something else.
This is not that and it never will be. If throwing water on hot stones is the point, buy a traditional cabin and be happier for it. The Zen range does exactly that from £1,802.
Four seats around a 1.8 metre circle is a lot of cabin, and a lot of room, for one person on a Tuesday evening. The Moon 2 seats two, costs about £1,300 less to buy and roughly half as much to run per session, and at about 10 amps it sits within what a plug and socket can carry.
The Moon is an indoor cabin. Hemlock and electronics in a British garden is not a plan, and nothing in the warranty would cover what happened next.
Infrared warms the body directly and the air around you stays far cooler than a Finnish room at 80 degrees. Holl's publish no air temperature for the Moon and we will not invent one. If walking into a wall of heat is what you are after, that is a traditional cabin's job.
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.
Not a rating. A record of where every figure on this page comes from: what we have checked against a published document, what a maker states and we have not yet checked, and what is still open.
- Dimensions, construction and output
-
Verified
Diameter, height, seat count, timber species, glass thickness, emitter count and the 4,620W total are taken from Holl's own specification sheet for the Moon range, edition 02/2026, and match the UK distributor's listing.
- Current drawn
-
Information not yet published
About 20A is our own arithmetic from the rated output at 230V. Holl's do not publish a current figure.
- Dedicated circuit
-
Information not yet published
Holl's state 220 to 240V and that the cable is not included. The 20A figure and the dedicated circuit that follows from it are our arithmetic at 230V, not a Holl's instruction, and the cable size and protection are for your electrician to specify.
- Weight, packages, assembly and lead time
-
Information not yet published
None of these appear on Holl's specification sheet. All four are being confirmed with the distributor.
- Warranty administration
-
Information not yet published
Ten years on the wood and two on the electrical components are Holl's published terms. How a claim is handled in the United Kingdom is being confirmed with the distributor before this sauna becomes buyable.
These states move as the evidence does. When a figure is measured on an installed cabin, by us or by an owner who will let us, it moves from stated to verified and this section says so.
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.