Calculator

Sauna electricity cost calculator

A transparent estimate built on assumptions you control.

Populate from a sauna (seller-listed electric heater kW)

Heater power

Electricity rate

$/kWh

From your utility bill.

Session length

min

Preheat time

min

Sessions per week

Average sessions per week; fractions represent an average over time.

Utilization factor

0–1. Share of time the heater draws full power (thermostat cycling).

Custom heater power and editable assumptions.

Methodology

kWh per session = heater kW × ((session minutes + preheat minutes) ÷ 60) × utilization factor. Cost = kWh × rate. Monthly = weekly cost × 52 ÷ 12.

Real usage depends on thermostat cycling, outdoor temperature and wind, insulation, door seals, heat-up time and the heater's actual draw. The utilization factor applies to the combined preheat and session period; actual preheat and session draw can differ. Default values are illustrative assumptions, not measurements.

Assumption-based estimate

Editable illustrative values — not measured use.

Energy per session4.20 kWh

Cost per session$0.71

Monthly$9.28

Annual$111.38

Electrical safety checklist

Get the heater's installation manual before you buy — breaker size and wire gauge come only from it.
220–240V sauna heaters are hardwired to a dedicated circuit. A standard 120V outlet is never a substitute.
Hire a licensed electrician to check panel capacity and pull any required permit.
Outdoor runs need weather-rated wiring and a code-compliant disconnect — your electrician decides the method.
Keep heater clearances exactly as the manual states; never place anything on the guard rail.
Test the installation with your electrician before the first full-heat session.

General guidance only — not wiring instructions. Your local code and the manufacturer's manual take precedence.

How do you calculate sauna electricity cost?

Multiply heater kW by total preheat and session hours, the estimated utilization fraction and your electricity rate in dollars per kWh. This is an assumption-based estimate, not measured consumption.

Illustrative example—not a national average

For a 6 kW heater, 40-minute preheat, 30-minute session, 60% utilization and $0.17/kWh rate: 6 × (70 ÷ 60) × 0.60 = 4.2 kWh, or $0.714 per session (about $0.71). At three sessions weekly, the tool estimates $9.28 monthly and $111.38 annually.

Choose assumptions for your routine

Utilization is the share of combined preheat and session time modeled at full heater power; the same factor applies to both. Actual cycling and weather may differ. Use your utility tariff, including applicable variable delivery charges. Fractional weekly sessions represent an average routine.

Monthly and annual estimates

Annual cost equals session cost × sessions per week × 52; monthly cost is annual cost ÷ 12. Wood-fired running costs are not estimated here. Seller-listed heater kW is not a measured energy-use figure.

Context source: Electric Power Monthly: Table 5.6.A, average electricity prices by state and sector — U.S. Energy Information Administration, accessed 2026-10-13. State averages are not your tariff or the calculator’s default rate.