How much does a sauna cost to run?
Enter your room, heater and electricity price. The same heat model as the heater calculator works out the warm-up, the time you spend inside, and what that adds to your bill.
A bigger heater doesn't cost more to run
The room loses heat the whole time it is warming up. A stronger heater gets there sooner, so less heat leaks away on the way. Same room, same time inside:
| Heater | Warm-up | Energy | Per session |
|---|
What a bigger heater does cost is a larger circuit. Breaker sizes by heater →
Monthly cost by sessions a week
What raises the cost most
An outdoor sauna in winter starts far below room temperature, so the warm-up takes longer. Try the winter option above.
A glass wall, a barrel or log walls lose heat faster, both while warming and while you sit inside.
Every extra hour inside adds the holding energy again.
Holding the heat costs energy every hour. Unless the next session is soon, switch it off and heat it again next time.
Questions
The heater draws a lot of power while it runs, but only for an hour or two at a time. Per session it uses a few kilowatt-hours to around ten, depending on the room.
Only if the next session is within an hour or so. For sessions days apart, heating it up each time costs less.
It is an estimate from a simple heat model of an insulated room with 6 air changes an hour. Real rooms vary with insulation, ventilation and how often the door opens. For a detailed room, use the full calculator.
It depends on what your firewood costs and how much a heating takes. Wood-burning stove sizes →
Size the heater for this room
Compare three sizing rules and see heaters rated for your room.