Choosing a garden sauna

Most people start with the look of a sauna. It’s better to start with the garden: where it will go, how it will get there, and how it will be powered. Get those right and the choice of model narrows quickly.

1. Who will use it, and how?

Think about how many people will realistically use it at once. Seat counts are the manufacturer’s maximum, so look at the bench layout if you’d like room to lie down or stretch out. If you like traditional high heat and steam, look at barrel and cabin saunas with a stove-type heater. If you prefer a gentler warmth, or want something indoors, infrared may suit you better. Our comparison guide goes into the differences.

2. Measure the space, then measure the route

• Measure the footprint including any roof overhang, and leave room to walk round it for maintenance and treatment of the timber.
• Check the height: it matters for planning (see below) and for overhanging trees.
• Measure the route from the road to the spot: gates, side passages, steps and tight corners. Saunas usually arrive as several large boxes or panels, plus the heater.

3. Do you need planning permission?

In England, garden buildings such as sauna cabins usually count as outbuildings and are often allowed under householder “permitted development” rights, without a planning application. The Planning Portal lists the main limits, including:

• No outbuilding on land forward of the principal elevation (usually the front of the house).
• Single storey, with a maximum eaves height of 2.5 metres and a maximum overall height of 4 metres with a dual-pitched roof, or 3 metres for any other roof.
• A maximum height of 2.5 metres if it’s within 2 metres of a boundary.
• No more than half the land around the original house covered by additions or other buildings.
• Different rules for listed buildings, and for designated land such as conservation areas, National Parks and Areas of Outstanding Natural Beauty.

Permitted development rights don’t apply to flats and maisonettes, and can be removed in some areas. If in doubt, ask your local planning authority before you buy.

4. Power: plug-in or hard-wired?

This is often the deciding factor. Traditional sauna heaters are commonly hard-wired on their own circuit. For example, Harvia’s published data for its 4.5 kW Vega heater specifies a 20 A fuse on a single-phase 230 V supply, and one UK retailer of a cabin using it states a dedicated 20 A hard-wired supply. Larger heaters draw more: by simple arithmetic, 6 kW at 230 V is about 26 A, so ask for the exact supply rating of the model you choose. Some infrared cabins are rated low enough to run from a standard 13 A supply. In England, installing a new circuit is notifiable building work under Part P of the Building Regulations, so you’ll need an electrician who can certify the work. Our site preparation guide explains this in more detail.

5. Timber and weather

Outdoor saunas are built from timbers such as spruce or thermo-treated spruce, which has been heat-treated to reduce moisture uptake. Whatever the timber, a sauna needs a level base that doesn’t sit in standing water, and some routine care. Check the manufacturer’s care guide before you buy.

6. Your budget, all in

Add up the whole job, not just the sauna:

7. Health and safety

Saunas and cold plunges aren’t suitable for everyone. If you’re pregnant or have a medical condition, ask your GP before using one, and always follow the manufacturer’s safety instructions.