& Holvi 300 Thermowood Barrel Sauna Gas — Aurora 81 safety pack

Steam & Oak Holvi 300 Thermowood Barrel Sauna Holvi is Finnish for vault, and a barrel sauna is exactly that: a barrel vault turned into a room. The curved staves lock against each other and the steel bands hold them in compression, so the shell carries its own load round the curve without a frame. The Holvi 300 is the three metre model in the range: 46mm thermowood staves, stainless steel bands as standard, two double glazed windows, and the choice of a covered porch at the door end or a longer hot room without one. With or without the porch The same 3 metre barrel can be built two ways, and the choice changes how you use it. With the porch. The first 60cm of the barrel becomes an open porch under the same roof, with a bench either side. That is where you cool down between rounds and keep towels and footwear dry, and it means the sauna door opens onto a sheltered space rather than straight into the weather. The hot room behind it is about 2.2 metres long inside, 8.24m³ of air. Without the porch. The door sits in the end wall and the hot room runs almost the full length of the barrel, about 2.7 metres inside and roughly 10m³. More bench length, more room to lie down, and a larger space to heat. 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. On most barrels stainless banding is an upgrade you pay extra for. 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, resists rot without chemical treatment, and holds its shape in a structure that depends on staying perfectly round. A note on wall thickness: 46mm solid staves give the barrel plenty of thermal mass, but how warm a sauna stays is governed far more by the glass, the ventilation and the heater than by a few millimetres of timber. We would rather you chose the Holvi for the layout, the bands and the build than for a thickness figure. Also available with gas — no electrician, no chimney, no fire to tend Pick a gas option at checkout and your barrel ships gas-ready: engineered ventilation built for gas, plus a bundled FinSteam gas heater package — ready to light on a UK propane bottle the day it lands. Steam & Oak is the only UK retailer offering this on a thermowood barrel. Hot in 15 minutes, turn a dial. The Aurora 81 is the only CE-marked electricity-free sauna gas heater on the European market (FinSteam's stated claim), and the heater that powers the FinSteam NOIR Signature packages. Why gas changes the equation Gas Wood Electric Heat-up time ~15 min, dial 30-45 min, tend a fire 30-60 min Electrician / wiring None None 50A circuit (£800-£1,500) Chimney / flue None Required None Smoke, ash, soot None Every session None Off-grid / power-cut Yes Yes No Humidity Naturally humid (combustion vapour) Dry until löyly Dry until löyly Running cost / session ~£2.00-2.50 £2-4 logs £2.00-3.25 Safety EU-cert, auto O₂ shut-off Open flame Electrical The real cost to your first löyly An electric sauna's shelf price is not the price to your first session. The 9kW Harvia needs its own dedicated circuit on 10mm² cable, wired by a qualified electrician and signed off under Part P — typically £800–£1,500, more again over a buried run to the end of a garden, plus the wait to get one booked. The gas heater connects to a propane bottle outside: no dedicated circuit, no trench across the lawn, and it is hot on the day it arrives. Against the wood fired M3, gas gives you the same freedom from the grid without the flue, the chimney route we would otherwise have to agree, or anyone building and tending a fire before every session. What gas-ready means The gas variants ship with wooden louvre vents at the FinSteam-specified sizes built into the barrel: intake ≥350 cm² low next to the heater drawing fresh air directly from outside, exhaust ≥250 cm² high in the opposite corner discharged directly to outside. FinSteam explicitly exclude plastic disc and twist valves. The vent configuration and the heater are certified together under EU Gas Appliance Regulation 2016/426. Pick a wood fired or electric variant and the barrel ships with the appropriate vent set for that heat type. Which gas option? Botnia 81 Our standard 8.1 kW gas heater. Everything you need to run the sauna. Aurora 81 The premium version of the same 8.1 kW heater — better finish and detailing. AENOR-tested under Reg 2016/426, ODS