Steam & Oak Holvi 170 Thermowood Barrel Sauna (Gas, Electric or Wood-Fired)

Steam & Oak Holvi 170 Thermowood Barrel Sauna

The Holvi 170 is the smallest barrel in the Holvi range: 1.7 metres long and 1.97 metres across, with a hot room of 3.9m³ and two benches facing each other. It is built from the same 46mm thermowood staves and stainless steel bands as the larger models, and it fits where a full size barrel will not, on a patio, a roof terrace or the corner of a small garden. Holvi is Finnish for vault, and a barrel sauna is exactly that: the curved staves lock against each other and the bands hold them in compression, so the shell carries its own load round the curve without a frame.

Why the bands are stainless

A barrel only stays round and tight because the bands keep the staves pressed together. Timber shrinks each time the sauna is heated and dries out, then swells again through a wet British winter, so the bands work constantly and need checking and re-tightening over the life of the sauna. Ordinary steel bands eventually rust, and rust runs down the timber and stains it. Stainless steel does not, and on the Holvi it is standard.

What thermowood actually does

Thermowood is timber that has been heat treated at around 200°C rather than chemically preserved. The process breaks down the sugars and resins that fungus feeds on and permanently reduces how much moisture the wood can reabsorb. The practical result outdoors is timber that moves less through wet British winters and resists rot without chemical treatment, in a structure that depends on staying tight.

Choose your heater at checkout

• Shell only. The complete sauna, you source your own heater.
• Harvia Cilindro PC70 6.8kW. The Cilindro pillar heater with its tall column of stones and controls built into the heater. Harvia rate it for rooms of 6 to 10m³.
• Harvia Cilindro PC70XW 6.8kW WiFi. The same heater with MyHarvia app control, so you can start it from the house. Supplied with the Harvia door sensor, which the electrical sauna standard requires before any heater can be started remotely.
• Harvia M3 wood fired. The classic Finnish log burning stove, rated by Harvia for rooms of 6 to 13m³. No electrics at all, no standing charge, and the ritual of building the fire. Supplied with a stainless steel chimney, and we confirm the chimney route with you before you order.
• Harvia M3 SL wood fired, through wall feed. The same stove, loaded through the wall from outside the hot room, so you feed the fire without letting the heat out or carrying logs past bathers.

Sizing the heater. Harvia size heaters on the room volume, then add 50% for solid log walls and about 1.2m³ for every square metre of glass, because both soak up heat that an insulated panel would not. The Holvi 170 hot room is about 3.9m³, which behaves more like 6m³. That is right in the range of the 6.8kW Cilindro, so that is what we offer.

We would rather sell you the right heater than the cheapest one. Tell us where the barrel is going and how you plan to use it, and we will confirm the choice with you before you order.

Also available with gas

Pick a gas option at checkout and the sauna ships gas ready: ventilation built for gas, plus a FinSteam gas heater package that runs on a standard UK propane bottle. No electrician, no chimney and no fire to tend. It heats in around 15 minutes from a dial.

• Botnia 81. Our standard 8.1kW gas heater. Everything you need to run the sauna.
• Aurora 81. The premium version of the same 8.1kW heater, with a better finish and detailing, oxygen depletion auto shut off and flame monitoring.
• With the safety pack. Adds the Njord heat shield and the Halo guard rail. The heat shield lets the heater sit closer to the timber wall, and the rail stops anyone brushing the hot stones. If you have children, guests, or you rent the sauna out, choose this one.
• Without the safety pack. Heater and stone cage only. Talk to us first, because in a curved barrel the wall leans in above the heater and we will usually recommend the heat shield.

FinSteam rate the 8.1kW heaters for barrels and other uninsulated rooms of up to about 8m³ of air, which is why gas is offered only where the hot room fits that range.

Every gas option includes the heater, the Orbis stone cage, 40kg of pre washed sauna stones, a UK propane regulator and CE marked gas hose, and our fitting and commissioning. The gas variants are built with wooden louvre vents at the sizes FinSteam specify: a low intake beside the heater drawing air from outside, and a high exhaust in the opposite corner. You source a standard 13kg propane bottle locally, and a fixed gas connection needs a Gas Safe registered engineer. See the full gas heater range.

Before you order: your electricity supply

The electric heaters are not plug in appliances. The 6.8kW heater has its own supply requirement and we confirm that with you directly rather than printing a figure here. Budget for a qualified electrician and a Part P sign off. The wood fired options and the FinSteam gas variants need no electrical supply for the heater.

Tell us your supply type and main fuse rating when you enquire and we will tell you honestly what will and will not work before you commit.

Build and finish

• Walls: 46mm thermowood staves
• Bands: Stainless steel tension bands
• Benches: Two benches in aspen or black alder
• Door: Multi layer glued timber door with a tempered double glazed window, wooden handle and lock
• Floor: 18mm timber floor boards
• Roof: Finnish bitumen shingles

What's included

• Barrel in 46mm thermowood
• Stainless steel tension bands
• Two benches in the hot room
• Glazed timber front door with handle and lock
• Timber floor
• Bitumen shingle roof
• Heat resistant heater protection plates
• Your chosen heater, on all variants except shell only, with the chimney on the wood fired options
• Harvia door sensor, on the WiFi versions
• Gas ventilation set, Orbis stone cage, 40kg stones, propane regulator and gas hose, on the gas variants

Options available

The Holvi 170 can be configured to suit your garden:

• Panoramic glass: tinted, toughened glass across half of the back wall, or the entire back wall with a heater safety fence
• Door: a tinted glass door, or a wood framed glass door with lock, in place of the timber door
• Benches: premium benches with back rests
• Roof: bitumen shingles in black, grey, red or green, or natural wooden shingles
• Lighting: LED strips under the benches and behind the back rests, in white or colour, and a sauna lamp with cover
• Comfort: head rests and back rests
• Safety: a timber heater safety fence
• Finish: factory painting in a choice of colours
• Accessories: bucket and ladle, thermometer and hygrometer, sauna hourglass, water tank for the wood stove

Ask us for a configured quote.

Specifications

• Length: 170cm
• External diameter: 197cm
• Height: 208cm
• Hot room: 3.9m³
• Seats: 2 to 4
• Wall thickness: 46mm thermowood
• Floor: 18mm
• Door: 69 x 160cm
• Weight: about 600kg
• Use: Outdoor only

Delivery and site preparation

• Delivery: Flat packed on one pallet, 200 x 120 x 120cm, around 600kg. You will need a way to move it from the kerb. Factory assembled delivery is also available, quoted separately, and needs a crane on the day.
• Lead time: confirmed at order
• Base: a stable, level base must be ready before delivery. Send us photos of your site and we will tell you what it needs.
• Electrical: for the electric heaters, see the supply note above. Qualified electrician required.
• Gas: standard UK 13kg propane bottle, sourced locally. Gas Safe registered engineer required for a fixed connection.
• Chimney: the wood fired options need a flue, with clearance from buildings and overhanging trees.
• Assembly: self assembly from the kit, typically two people over one to two days

Want a terrace to sit out on? The Holvi 240 adds a covered 60cm terrace. Not sure which configuration suits your garden? Read our complete UK Sauna Buying Guide, or message us and we will confirm the specification with you before you order.