15kW+ Sauna Heaters

15kW+ sauna heater outputs: the 15, 16 and 18 kW models here

Harvia rates its Club K15G at 15 kW and its Virta Pro HL160E at 16 kW, and HUUM rates the HIVE 15 at 15 kW and the HIVE 18 at 18 kW.

The Harvia Club listing also sells 10 and 12.5 kW models, and the HUUM HIVE heater listing a 12 kW model. If you buy either one for its larger outputs, choose the Club K15G, or the HIVE 15 or HIVE 18, from the options on its product page.

Saunum's Air L package is filed here too; its output and room-size figures are on its product page.

15kW+ sauna heater families compared

Harvia, HUUM and Saunum make the 15kW+ sauna heaters here, and their families differ in stone load, control, mounting and what ships with the heater.

Harvia Club K15G (15 kW)

Harvia's Club K15G, from the Harvia Club sauna heaters, runs from a separate Harvia Xenio control, which Harvia makes in Wi-Fi (-XW) versions that connect to the MyHarvia app, and Harvia's manual has the Club secured to the floor with at least two screws or bolts.

Harvia Virta Pro HL160E (16 kW)

Harvia's Virta Pro HL160E stands on the floor, levelled on its adjustable legs. It runs from a separate Harvia control: its manual pairs it with the Xenio CX45, alone or with the LTY45 power extension, on two circuits, or with a CX30 or CX45 plus the LTY45 on four circuits, and Harvia's Wi-Fi control versions (Xenio -XW, Fenix) connect to the MyHarvia app.

HUUM HIVE 15 and HIVE 18

HUUM's electric HIVE, one of the HUUM HIVE sauna heaters, stands on four adjustable legs and needs a separate control, which HUUM pairs with its UKU. The UKU runs heaters up to 11 kW on its own, so the HIVE 15 and HIVE 18 also need HUUM's UKU Extension Box, with which HUUM rates the UKU for heaters up to 18 kW. The UKU can be set up to 230°F (110°C), or 194°F (90°C) with its bench sensor fitted; a UKU Wi-Fi runs the heater from the HUUM mobile app, while the UKU Local is run from its wall panel only, with no app.

Saunum Air L package

Topture's Saunum Air L package combines an Air L heater with its climate-equalizing module (Air L 10, 13 or 15, the option chosen), the Saunum Air IQ Wi-Fi control with its power unit, door and temperature sensors, and sauna stones. Saunum's US manual says the Air L is designed to operate only with that separate Air IQ control, whose manual adds remote control through the Saunum mobile app.

Pick between the 15kW+ sauna heater families by what the room needs most:

• Stone mass: choose a HUUM HIVE for the heavier load, since its stone capacity is 551 lb (250 kg), against a maximum stone load of 200 lb for Harvia's Virta Pro 16 kW and a stone amount of 132 lb for the Club K15G.
• A heater set into the bench or floor: choose a HUUM HIVE, which HUUM allows to be partially set into the sauna bench or floor with its embedding flange; rule out the Club, since Harvia's manual says its KG heaters are not approved for installation in a recess in the wall or floor.

15kW+ sauna heater supply: 240 V, 208 V three-phase and the makers' amps

Every 15kW+ sauna heater listing here comes in a 240 V version. Harvia's Club manual lists 240 V single-phase and 208 V three-phase versions, and the Club listing sells both, which makes the Club the one listing here with a three-phase option.

HUUM's US manual gives the HIVE 15 at 62.5 amps and the HIVE 18 at 75 amps on 240 V. Harvia's manuals give the Virta Pro 16 kW at 66.7 amps in total on 240 V single-phase, wired as 2 or 4 separate circuits (up to 33.3 A per circuit on two, up to 22.3 A per circuit on four), and the Club K15G at 61.7 amps on 240 V single-phase or 40 amps on 208 V three-phase. Saunum's figures for the Air L are on its product page.

Choose the Club in its 208 V three-phase version if your building's supply is three-phase; on a 240 V supply, compare the makers' amps with what your electrician says the service can carry. Your licensed electrician sizes the breaker and wire from the manual that ships with the heater and your local code.

15kW+ sauna heater room sizes by maker's range

Harvia, HUUM and Saunum each size a sauna heater to the room's volume, with an allowance for uninsulated walls. Harvia's manuals add about 3.9 cu ft per square foot of uninsulated wall such as glass, brick, concrete or tile, glass doors included, and multiply a solid-log room's volume by 1.5. HUUM's manuals add 3.3 cu ft per square foot of uninsulated brick, tile or glass wall. Saunum's manuals multiply the volume by 1.5 for log, plank or stave walls without internal insulation, add 3.0 cu ft per square foot of glass, tile, brick, concrete or stone, and say to choose the larger heater when the result falls between two sizes.

With the allowance added, choose the 15, 16 or 18 kW model whose maker's range covers the room:

• Under 530 cu ft: choose Harvia's Virta Pro 16 kW, sized for 354–918 cu ft; below 354 cu ft, rule out every 15, 16 and 18 kW model here.
• 530 to 813 cu ft: choose HUUM's HIVE 15, sized for 530–813 cu ft, or the Virta Pro 16 kW; from 630 and 636 cu ft respectively, Harvia's Club K15G and the HIVE 18 cover the room too, so the supply and the stone mass decide between them.
• Over 813 cu ft: choose the Virta Pro 16 kW up to 918 cu ft, HUUM's HIVE 18 (636–989 cu ft) up to 989, or Harvia's Club K15G (630–1,000 cu ft) up to 1,000; above 1,000 cu ft, none of these models is sized for the room.

15kW+ sauna heater packages, controls and stones

Topture's HUUM HIVE 15kW and 18kW packages each combine the heater with a HUUM UKU control (UKU Local Black, or UKU Wi-Fi with a Black, Glass or Mirror panel), HUUM's UKU Extension Box and HUUM Stones 24.

Three listings here sell the heater alone, HUUM's HIVE and two Harvia listings, and each ships without stones. Their product pages offer the stones and a control as add-ons.

• No control or stones yet: choose one of the three packages here, the two HIVE packages or Saunum's Air L package, each sold as one item with its control and stones.
• A compatible control already on the wall: choose the heater alone and add the stones from its product page, with whatever the maker's pairing above still calls for: HUUM's UKU Extension Box for a HIVE 15 or 18, or Harvia's LTY45 power extension for a Virta Pro 16 kW on four circuits.

Freight on each of the six 15kW+ sauna heater listings here is included within the contiguous United States. Topture is an authorized Harvia retailer and an authorized HUUM and Saunum retailer, and HUUM's official dealer directory lists it as an "E-shop"; shipping, warranties, expert support and paying over time are covered on the sauna heaters page.

Next steps from a 15kW+ sauna heater: 12kW, big-room collections or sizing help

Where to go from a 15kW+ sauna heater depends on the room and the supply:

• A room below the ranges here, or a supply that cannot carry these heaters' amps: compare the next output down on 12kW sauna heaters.
• Still comparing big-room heaters across outputs: browse large sauna heaters or commercial sauna heaters.
• Room volume, glass area or wall construction still open: send the room's dimensions, glass area and wall construction to Topture's Lifetime Expert Support for help sizing the heater; call (833) 419-1774, use live chat or write to contact@topture.com.

Reviewed October 2026