What sauna installation actually costs
For a commercial installation in Ireland, the cabin is rarely the biggest surprise on the invoice. A four-to-six person electric cabin typically lands between €6,000 and €14,000 supplied, with outdoor barrel and cube units at the upper end once cladding, roofing and a weatherproof base are included. Wood-fired units cost less to run but more to site, because the flue, hearth clearance and fire safety sign-off all add work.
The line items operators consistently underestimate are the electrical supply, the base or plinth, and ventilation. A dedicated circuit for a 6–9kW heater is normal; anything above 9kW usually needs three-phase, and if the board is already loaded you are paying for an upgrade before you pay for a sauna.
- Cabin supply: €6,000–€14,000 for a commercial 4–6 person unit.
- Heater and controller: €900–€2,500 depending on kW and whether the control is external.
- Electrical works: €600–€2,500, higher if a three-phase supply or board upgrade is needed.
- Base, plinth or decking for outdoor units: €800–€3,000.
- Ventilation, benching adjustments and finishing: €400–€1,500.
Sizing the heater to the cabin
The working rule is roughly 1kW of heater per cubic metre of cabin volume, then add capacity for anything that steals heat: glass panels, uninsulated stone or concrete walls, and exterior-facing surfaces on outdoor units. Undersizing is the most common installation mistake and it never resolves itself — the cabin simply takes 70 minutes to do a 40 minute job, every day, forever.
Our sauna calculator does this sizing for you and estimates heat-up time and daily running cost from your dimensions and electricity rate.
Ventilation, the part everyone skips
A commercial cabin needs a low inlet near the heater and a high outlet on the opposite side, sized for roughly six air changes per hour. Without it, CO2 and VOC levels climb through a busy session, the top bench gets stale, and guests report headaches they will blame on the heat rather than the air.
If you are monitoring the cabin, ventilation is where the data pays for itself: CO2 climbing session over session is the earliest signal that airflow is inadequate or an outlet has been blocked.
Installation timeline
For an indoor retrofit into an existing room, plan two to four days: one for electrical first fix, one to two for the cabin build, and a half day for commissioning and the first controlled heat cycle. Outdoor installs add base preparation and delivery access, which typically pushes the whole job to one to two weeks including curing time on a concrete plinth.
Commissioning checks before you open
Do not let a first heat double as a first booking. Run a full cycle from cold with nobody in the cabin and record what happens.
- Time to reach 80°C from cold — establish the baseline you will measure drift against later.
- Bench-height temperature, not stove or ceiling temperature.
- Humidity response to a löyly pour, and how quickly it settles.
- Air quality through a simulated busy hour, with the doors used as they would be in service.
- Recovery time between back-to-back sessions.
- Emergency stop, door swing, lighting and signage.