HUUM heaters compared

The short version: HUUM makes six electric families. Drop is the wall heater. Cliff, Steel and Core are slim floor columns that can be embedded into a bench. Hive and Hive Mini are the rock towers, with Hive holding 250 kg of stone. Every one of them requires a separate UKU control system, sold separately, in Local, Wi-Fi or GSM form. HUUM publishes room volumes in cubic meters and never in cubic feet — the Amazon listings translate, its own site does not — and it publishes no warranty length or heat-up time on any HTML page.

The lineup by output and volume

Two practical notes on that table. The 10.5 kW versions of Cliff, Steel and Hive Mini are not available single phase, so a US home without three-phase service tops out at 9 kW in those families. And Core holds only 40 kg of stone — the lowest in the range — because it is designed to disappear into a bench rather than to be a rock tower. If stone mass is what you are buying, Steel and Hive are the ones. Our sauna heater sizing guide converts your room to the metric figures HUUM uses.

Current, fuses and what your electrician will ask

• Drop: 20 A at 4.5 kW, 32 A at 6 kW and 40 A at 7.5 and 8.5 kW on single-phase 230 V; 10 to 16 A on three-phase 400 V. US pages list 240 V with fuses from 30 to 50 A.
• Cliff and Steel: 32 A at 6 kW and 40 A at 9 kW single phase; the 10.5 kW is three-phase only.
• Core: 32 A, 50 A and 63 A at 6, 9 and 10.5 kW single phase — the heaviest single-phase draw in the range.
• Hive: three-phase only on HUUM's European pages; US listings show 240 V with twin 30 A or twin 50 A fuses.
• Every model needs a heat-resistant supply cable and a UKU control unit, both sold separately.

HUUM also publishes safety distances per model and per output — A, B, C and H figures on every product page — and a line that matters more than it looks: the manufacturer's warranty is invalid if the heater and the sauna room have been dimensioned incorrectly. In other words, undersizing or oversizing is not just a comfort problem with this brand. Our outdoor sauna electrical guide covers the circuit side.

Bench embedding, which is the HUUM signature

Cliff, Steel and Core are all designed to sit partly inside a bench: Cliff and Steel need at least 550 mm protruding above the bench surface, Hive Mini needs 350 mm, and Core can be embedded along its full length. That is how HUUM gets a 9 kW heater into a room without a column in the middle of the floor, and it is a genuinely different installation to plan for than a wall unit — the bench has to be built around the heater, not before it. Our Finnish sauna guide covers why the foot bench must still sit above the stones whatever you embed.

The UKU control is not optional

Every HUUM electric heater is sold without controls. UKU Local is the panel alone; UKU Wi-Fi adds the app; UKU GSM covers saunas outside Wi-Fi range, which is a real answer for a garden sauna at the end of a plot. Panels come in glass, classic and wood finishes, and the system can also switch sauna lighting, ventilation and a steamer. Budget for it: on Amazon the HUUM listings that include a UKU are bundles, and the price difference against a bare heater is the controller. See best sauna controllers for the wider field.

Converting HUUM's metric ratings

HUUM rates rooms in cubic meters, and a cubic meter is 35.3 cubic feet. So the common bands come out as roughly 106 to 177 cubic feet for a 3–5 m³ Mini, 177 to 318 for the 5–9 m³ 6 kW models, 282 to 459 for the 8–13 m³ 9 kW models, and 353 to 565 for the 10–16 m³ 10.5 kW versions. A 5 × 7 room with a 7-foot ceiling is 245 cubic feet, or 6.9 m³ — comfortably a 6 kW Drop, Cliff, Steel or Core, and a Hive Mini if you want the stone mass. Doing that conversion yourself is unavoidable with this brand unless you are shopping from the Amazon listings, which quote cubic feet that HUUM's own site does not.

Which HUUM for which room

What HUUM does not publish

• A warranty length on any HTML page — the terms are a PDF we could not read.
• Any heat-up time, for any model.
• Cubic-feet room ratings — metric only, while its Amazon listings quote cubic feet.
• Mounting type for the full-size Hive on its product page.
• Specifications for the new Core Wall family, which is listed but not detailed.

HUUM or Harvia

Harvia publishes cubic feet, sells more control variants with built-in dials, and is easier to buy in the US through several retailers. HUUM publishes fuse sizes and safety distances in more detail, builds the better-looking object, and requires a separate controller on every model. On stone mass they meet in the middle — a Harvia Cilindro at 176 pounds against a HUUM Steel at 330. Our Harvia vs HUUM page runs that comparison directly, and Harvia heaters compared covers the other lineup.

Every pick on this page comes from published specifications, not from hardware we own. Read how we pick — including what spec-led ranking cannot tell you.