Sauna Running Cost Calculator
What does it actually cost to use your sauna? Adjust dimensions, heater type and electricity price — and get heat-up time, kWh per session, and monthly cost instantly.
Sauna & usage
How the cost is calculated
For electric heaters we compute the energy to heat the air (volume × ΔT × ρ × c) plus a thermal-mass factor (~3×) for walls, benches, and stones. We divide by the heater's efficiency and add the maintenance load during the session. For wood-fired we use an empirical model based on ~15 kg of birch per session.
How long does it take to heat a sauna?
35–60 minutes for a correctly sized electric heater to reach 80 °C. An undersized heater never reaches temperature, an oversized one wastes energy. Wood-fired saunas take 30–60 min depending on size and chimney draw.
Is wood-fired or electric cheaper to run?
At average European 2024 electricity prices (0.30 €/kWh) both come out around €4–6 per session for a typical 8 m² sauna. At high prices (0.50+ €/kWh) wood becomes clearly cheaper; at very low rates electric wins on cost and convenience. Wood also requires fuel handling and (in Sweden) a chimney/fire-place declaration.
How much does good insulation save?
An uninsulated outdoor log-cabin uses about 30 % more energy than an insulated build. Glass doors and windows further increase losses — each m² of glass adds roughly 1.5 m³ of effective volume.