Guide

Garden sauna electrics: 13 A plug, dedicated circuit or three-phase?

Which saunas run from a normal socket, which need a new circuit, and why a 9 kW heater can mean a 50 A supply.

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Most traditional garden saunas need a new circuit from your , fitted by an electrician. Only small infrared cabins under about 3 run from a normal 13 A plug. Check this first. It can add £450 to over £1,000 to the price.

What a normal socket can supply

A normal socket can safely supply about 3 (kilowatts, a measure of power). That is 13 amps × 230 volts = 2,990 watts, our calculation. Garden sauna heaters are usually 4.5 to 9 kW, so they can't run from a plug. They need their own cable from your , called a . Small infrared cabins for one to three people use about 1.6 to 1.9 kW, so many of them can plug in.

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The three levels of electrics

What the sauna needs	Typical heaters	What we add to the price
Normal 13 A plug	Infrared cabins up to about 3	£0
	4.5 to 8 kW electric heaters, larger infrared cabins	£450
50 A single-phase or	9 kW and larger heaters	£1,150

Where our figures come from: Summerhouse24 says £300 to £600 for a dedicated circuit, and Steam & Oak budgets £800 to £1,500 where a 9 kW heater needs a bigger supply. We use the middle of each range. A long cable run down the garden costs more. For example, the heater maker Harvia says its 9 kW Cilindro heater needs either a three-phase supply or a 50 amp single supply, both much bigger than most homes have spare. Your electrician's quote is the real figure: type it into the calculator on any sauna page.

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Who can do the work

In England a new circuit must be signed off under the Building Regulations (the part called ). So use an electrician who belongs to a registered scheme, such as NICEIC or NAPIT, and can give you a certificate. The wiring rules also treat a sauna as a special case, so tell the electrician what the circuit is for. We don't give electrical advice. Before you order, ask the electrician to check that your and main fuse can take the extra load.

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What to check on a listing

The heater's power in (kilowatts), and whether the heater is included in the price.
What supply the seller says it needs. Many listings don't say; we show "not published" and count a to be safe.
The distance from your to where the sauna will stand. Longer cable runs cost more.
Whether you want a wood-burning stove instead: no electrics, but see the smoke rules.

The sauna finder filters by the power you have.

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Common worries

"The electrics sound like a nightmare."

It is one visit from a registered electrician. Every sauna page says what power it needs, and we add a typical cost to the price (£450 for a new circuit). 8 saunas we list plug into a normal socket, and 46 garden saunas take a wood stove with no electrics at all. Sauna electrics, explained →

"With energy prices what they are?"

About £1.97 a session for a 6 heater at 26.32p per , or about £0.53 for an infrared cabin. Twice a week, that is about £205 a year. A wood-fired stove uses £80 to £180 of logs a year instead. Your own running cost →

All ten sauna worries

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