The best sauna heaters

The Vega BC60 is a 6kW wall heater, and SaunaShop sells it for £366 with about 20kg of stones in the box. Harvia rates it for rooms of 5 to 8m³, which covers a typical 2 to 4 person cabin with insulated walls. The timer and thermostat dials are on the heater itself and can go on either side, so there is no control panel to buy or wire.

Its limit is the stone load. 20kg heats quickly but gives a sharper, shorter burst of steam than a pillar heater carrying 80kg, and the built-in thermostat reads the heater's own temperature rather than the air at bench height. It needs its own circuit: Harvia lists a 35A fuse on a single-phase supply, or 3 × 10A on three-phase.

Among the 6kW heaters we priced, none comes complete with stones for less. Size the room first if it has a glass front or bare log walls, because those surfaces can push a 6m³ cabin past what the Vega is rated for.

The Cilindro PC70 stacks 80kg of stones in a stainless steel pillar 32cm across and 93cm tall, and SaunaShop sells it with the stones for £513. That is 4 times the Vega's stone load for £147 more. It is rated at 6.8kW for rooms of 6 to 10m³, with the timer and thermostat built into the base.

A big stone mass changes the steam. Water on top of the pillar gives a sharp hit, water on the sides comes back softer, and the stones keep giving heat after the thermostat clicks off. Harvia's own advice is to step up 1kW when you swap a wall heater for a pillar, because the extra stone takes longer to heat.

It needs 32cm of floor plus 10cm clear on every side, which is a lot to give up in a small indoor cabin. If your sized volume lands near 10m³, Harvia points you to the 9kW PC90 instead, which SaunaShop sells for £567 and which wants a 40A fuse on single-phase.

The HIVE Mini holds 150kg of stones on a 6kW heater, nearly double the Cilindro's load, in an open steel cage 46cm across and 75cm tall. HUUM rates the 6kW version for rooms of 5 to 9m³. More stone means a slower start and a longer, gentler steam, closer to a wood stove than a wall heater.

The price on the box is only part of it. Finnmark Sauna sells the 6kW heater for £729.99, but it has no controls of its own and runs from a HUUM UKU controller, £394 for the Local version and £579 with Wi-Fi. Add 150kg of stones, about £320 in 20kg boxes of olivine diabase, and the real cost is nearer £1,450.

For that you get the best steam on this page from an electric heater. The UKU's sensors read the room rather than the heater, so the temperature holds closer to what you set, and the supply is a 32A fuse on single-phase, a little less than the Harvias need.

If there is no realistic way to get a 32A circuit to the sauna, a wood stove is the answer, and the HIVE Wood 13 is the one we'd buy. It carries 90kg of stones, 3 times the Harvia M3's 30kg, for rooms of 6 to 13m³. Finnmark Sauna sells it for £1,010, down from £1,242.

The stove is only the start of the bill. Stones are extra, about £200 for 90kg, and so is the flue: HUUM's through-the-wall chimney set is £727 at the same shop and the through-the-ceiling set £918.99. The outlet is 115mm, logs can be up to 30cm long, and HUUM wants a non-combustible base at least 60mm thick under it.

Running costs drop to the price of dry logs, and no electrician is involved. The trade is time and effort: every session starts with lighting a fire, and HUUM says the chimney and flue need cleaning at least once a year.

The M3 is the plain black Harvia stove that several garden cabin makers offer as their wood option, and SaunaShop sells it for £464 with stones. Harvia rates it at 16.5kW for rooms of 6 to 13m³, with a glass door and a 115mm flue outlet at the top or back. A pipe water heater can be fitted on its flue.

The low price buys a small stone load. 30kg heats fast and gives a lively steam, but it cools quickly when the fire dies down, so you feed the stove through the session rather than letting the stones carry you. Harvia lists 250mm to combustible walls at the sides and 1.2m to the ceiling.

Budget for the flue and, in a tight cabin, a heat shield on top of the £464. SaunaShop's shield kit for the M3 starts at £209 and lets the stove sit closer to the walls and benches.

The DROP is a rounded steel cage that hangs on the wall and still holds 55kg of stones, nearly 3 times a Vega's load, so a small cabin gets softer steam without giving up floor. HUUM rates the 6kW model for rooms of 5 to 9m³, and Finnmark Sauna sells it for £488, down from £639.

Like the HIVE Mini, it has no controls of its own. The UKU Local controller adds £394 and 55kg of stones about £120, which takes a £488 heater past £1,000 before the electrician arrives. It runs on a 32A fuse on single-phase, and a larger DROP for rooms of 8 to 13m³ costs £569.

Pay that when the heater is on show through a glass door and the look matters. On heat and steam per pound, the Cilindro does more for about half the money.