Saunas FAQ (indoor/outdoor, heaters, placement)

Saunas FAQ

Saunas raise more pre-purchase questions than any other product we sell — partly because UK buyers come from radically different reference points (gym sauna, Finnish authenticity, infrared health claims, garden room conversion), partly because the install details (electrics, base, planning, placement) are genuinely consequential. This FAQ answers the questions UK buyers ask most often, with practical numbers rather than catalogue marketing. We're a UK retailer working with accredited UK distributors (Hekla, Fonteyn, Harvia and others); every answer here reflects what the actual hardware does in a real UK garden or home.

Can I use a sauna every day?

Yes — daily sauna use is safe for most healthy adults and is associated with measurable health benefits. The most-cited research is the Finnish KIHD cohort (Laukkanen et al., 2015 onwards), which followed 2,300+ middle-aged men for ~20 years and found that men using a sauna 4–7 times per week had ~50% lower cardiovascular mortality than once-weekly users, with similar protective effects on dementia risk and respiratory illness. The typical session length in those studies was 15–30 minutes at 80–100°C — well within what a domestic Finnish-style cabin like the Hekla Cube range or Fonteyn Uwais delivers. Hydration matters — 500–750 ml of water per session — and people with cardiovascular conditions, pregnancy, or uncontrolled blood pressure should consult their GP before establishing a daily routine. For infrared cabins running at 50–60°C, daily sessions of 30–45 minutes are well-tolerated and easier to sustain as a habit. See our Sauna Health Benefits guide for the full research summary.

Do outdoor saunas need electricity?

For nearly all outdoor saunas sold in the UK: yes. The exceptions are wood-fired saunas, which use a log-burning stove with no electrical heater — but even those typically need a small electrical supply for lighting, control panel, and any ventilation fan. Electric Finnish-style saunas (the most common type — Hekla, Fonteyn, most Harvia-heated cabins) need a dedicated single-phase or three-phase supply depending on heater wattage: a 6.8 kW heater typically runs on a 32A single-phase circuit, an 8 kW heater on a 32A single-phase or low-load three-phase, and larger 10+ kW commercial-spec heaters typically need three-phase. Infrared cabins (Hekla IR100/130/160) are far simpler — they plug into a standard UK 13A 3-pin socket with no electrician needed for the supply itself. For all outdoor electric saunas, the supply should be installed by a qualified electrician to BS 7671 (current 18th Edition) with an outdoor-rated isolator, RCD protection, and appropriate cable sizing for the run. Browse our full sauna range for electrical requirements per model.

Indoor or outdoor sauna — which is better?

Both work; the choice usually comes down to space and routine. Indoor saunas (a spare bedroom, garage conversion, or dedicated home-gym space) get used more often because the journey is short — slippers, ten paces, in. They suit infrared cabins particularly well because the simpler power requirement removes the install overhead. Outdoor saunas (a garden barrel, cube, or cabin) deliver a more ritual experience — walking out into a properly-built cabin under cold air is part of what makes contrast therapy work — but the install is a bigger project. For most UK households, the right answer is whichever location matches the routine you'll actually maintain.

Infrared or traditional — which indoor sauna?

Different physiology, different routines. Infrared cabins (50-60°C, dry radiant heat from carbon panels) heat your body directly rather than the air around you. They reach a usable temperature in 10-15 minutes, plug into a standard 13A socket, and run at ~£0.60-£0.90 per session — built for daily 30-45 minute recovery sessions. Browse Indoor Infrared Saunas from £1,195.

Traditional Finnish saunas (80-100°C, hot stones with water-on-stones löyly) deliver the proper Finnish ritual. They take 30-45 minutes to warm up, need a dedicated 16A or 32A circuit (qualified electrician), and run at ~£1.75-£2.25 per 90-minute session — built for shorter, more intense sessions in the classic style. Browse Indoor Traditional Saunas from £4,499.

If you want the full Finnish ritual (high heat, löyly, cold contrast), buy traditional from the start — infrared is a different stimulus, not a stepping stone.

Barrel vs cabin/cube — what's the difference?

Barrel saunas heat faster and use less wood/electricity because the curved interior reduces the air volume to heat; they have a distinctive aesthetic and tend to be cheaper per square metre. Cabin/cube saunas are more space-efficient for seating and easier to fit against a fence or wall; the flat-pack assembly is more straightforward than barrel staving. Our Hekla 250 Barrel and Hekla Cube 250 are direct comparables — same 6-person capacity, similar pricing, different geometry.

What size sauna do I need?

Match the cabin to the people who'll actually use it most weeks — not the maximum theoretical group. Oversizing wastes electricity (a 6-person cabin heating for one user costs the same as for six) and takes longer to reach temperature.

  • Solo or recovery use: 1-person infrared (browse) — fits a corner, fastest warm-up
  • Couples / solo with stretch room: 2-person infrared (browse) or 2-3 person traditional (browse)
  • Small family / friends: 3-person infrared (browse) or 3-4 person traditional (browse)
  • Family + occasional guests: 4-5 person traditional (browse)
  • Hosting / social use: 6+ person traditional (browse) or large outdoor barrel/cube

For outdoor, the same principle applies plus garden footprint constraints — a 4-person barrel needs roughly a 2.5m × 2.5m base; a 6-person cube cabin needs ~3.0m × 3.0m. See our Site Prep Checklist for full dimensions per cabin type.

Do I need planning permission?

For most domestic outdoor saunas in the UK: no, planning permission is not required under "permitted development" rights, provided the structure is single-storey, under 2.5 m tall, sited at least 2 m from any boundary if the eaves exceed 2.5 m, and within the rear-garden curtilage. Exceptions: properties in conservation areas, listed buildings, AONBs, and properties without permitted development rights (some new-build estates). Building Regulations also typically don't apply to a sauna under 15 m² floor area if it's a "garden building" rather than a habitable room. Always check with your local planning authority before commissioning a large outdoor build — a quick phone call saves expensive rework.

What base do I need for a sauna?

A solid, level, load-bearing base is essential — uneven decking, soft gravel, or a sloping lawn will warp the cabin and stress the heater. Standard options: a 100 mm reinforced concrete pad sized to the cabin footprint plus 200 mm overhang on each side; paving slabs on a compacted MOT Type 1 base; or a properly engineered timber deck rated for the loaded weight (a 4-person cabin with users, water, and snow load can exceed 1,500 kg). Avoid uneven natural decking unless engineered for the load; avoid grass or bare soil without a base.

How long does a sauna take to heat up?

Heat-up times depend on heater wattage, cabin volume, and outdoor temperature. As a rough guide: an 8 kW Finnish heater in a 4-person cabin typically reaches 80–90°C in 30–40 minutes from a UK summer ambient (~20°C), and 40–60 minutes from a winter ambient (~5°C). A 6.8 kW heater in a 2-person cabin: 20–30 minutes. Infrared cabins (Hekla IR100/130/160) deliver a usable session profile within 10–15 minutes of switching on — materially faster than convective Finnish heat. For comparison, a sauna stove typically takes 60–90 minutes to reach session temperature.

What's next

If you're narrowing down a specific model, jump straight to the right collection:

For the full pre-purchase walkthrough, read our UK Sauna Buying Guide — written by founder Sarb Gill (BSc Biology) covering wood-fired vs electric vs infrared, real running costs, install requirements, and what to avoid. For the infrared vs traditional decision in depth, see our Infrared vs Traditional Sauna comparison.

Need help matching a sauna to your space and electrics? Email help@steamandoak.co.uk with your postcode and a photo of the intended location.