Sauna Solar Calculator

Country / solar region

Uses average annual PV output as a simple solar yield estimate.

Electric sauna heater size

The heater size is the main electrical load.

Session length

Hours, including heat-up time.

Sessions per week

How often the sauna is used.

Heater duty factor

Allows for heater cycling once the sauna is hot.

When will it mostly be used?

Evening use needs more battery storage.

Battery reserve days

More reserve means a larger battery.

Solar panel size

Used to estimate panel count.

System loss allowance

Covers inverter, angle, weather, cable and conversion losses.

Recommended solar setup

0 kW Suggested solar array size

Average solar yield 0 kWh/kWp/day

Energy per sauna session 0 kWh

Average daily sauna energy 0 kWh/day

Battery storage suggested 0 kWh

Inverter output suggested 0 kW

Estimated panel count 0 panels

Setup type -

Enter your sauna details to estimate the system.

This is an estimate only. Real performance depends on roof angle, shading, season, battery limits, inverter output, heater wiring, local regulations and installer design.

Get help sizing your setup

Frequently Asked Questions

Can I run a sauna heater on solar panels alone?

Only with a serious battery. A heater pulls hard for a short burst, usually in the evening, exactly when the panels have stopped producing. It will tell you when that gets silly.

What size solar array and battery does a sauna need?

Enter heater size, sessions a week and your country and it returns array kW, battery kWh, inverter kW and a panel count, using that country's own average yield figure.

Why does evening sauna use need so much more solar?

Because none of it comes straight off the panels. It all has to be stored first, so the battery grows and the array grows with it. Daytime sessions need far less of both.

Does a sauna need more solar panels in Scotland than Spain?

Roughly double. Around 90 countries are listed with their own average yield, from 2.7 in the UK to 5.0 in Spain, and the array is sized against that figure.

Can the solar calculator work from panels I already have?

No, it runs the other way round. You describe the sauna and it sizes a new system. Electric heaters only, since a wood stove needs no supply at all. See the wood-fired guide.