Feature Review
HUUM heater review: how the Drop 6, Cliff 9 and Hive 12 compare
These three Estonian heaters carry more stone than anything else at their wattage. We match each one to a room and list the wiring and controller it needs.
By Adam Bognar, Editor
HUUM's Drop 6 suits a small room, the Cliff 9 a tight one and the Hive 12 a big one. We compared the stone load and price of the three sizes you'll meet as a home buyer, and we've added the wiring and controller costs the product photos leave out. HUUM is an Estonian company that treats a sauna heater as an object worth looking at, and two of its designs have won Red Dot awards. Under the looks, every HUUM carries far more rock than a conventional heater of the same wattage, which takes the Harvia Cilindro's principle further.
Stone capacity decides the steam a heater can make
The steam you get when you throw water on a sauna heater depends on how much stone is hot. A heater's wattage sets how fast it warms the room and doesn't tell you that. The hot stone stores heat and gives it back in one wave when the ladle hits. A conventional 6 kW wall heater holds roughly 40 pounds of it in a tray on top of the elements.
HUUM's Drop 6 packs about 121 pounds of stone into a body the size of a large lantern. The Cliff 9 takes up to 165, and you fill the Hive 12's open basket by the sackful. With that much hot stone, each ladle throws a bigger, wetter wave that lasts longer, and the room rides through a long session without the elements cycling.
The Drop 6 gives a small room a big stone load
The Drop 6 is HUUM's droplet-shaped 6 kW wall heater, and its design won a Red Dot award. It suits small to mid-size home saunas for roughly two to four people. You'd buy it for the stone load, since it packs around 121 pounds into a compact wall-mounted body, and that much stone gives a small room steam it usually can't get.
We priced it at Sauna Kit Co, which sells it as a $3,150 package with HUUM's UKU Wi-Fi controller and the stones, so the price covers everything except the electrician. The UKU is a separate wall control that lets you start the heater from your phone. It comes in the Drop package and costs extra with the other two sizes, so ask about it before you compare prices. A heater listed without its controller isn't cheaper once you've added one.
Where to buy
HUUM DROP 6 6.0kW Sauna Heater Package. HUUM photography.
See the specifications and priceThe Cliff 9 fits rooms with no clearance to spare
The Cliff 9 is a slim floor-standing 9 kW heater, and it's also a Red Dot winner. HUUM built it for saunas where the wall and bench layout leaves almost no clearance to give up, and its safety distances are unusually small for the wattage. An internal air tunnel speeds heat-up by about a quarter, according to HUUM. The Cliff holds up to 165 pounds of stone.
At $2,638, it's the heater we'd price for a four-to-six person room that a box heater would crowd. The UKU controller costs extra here, so add it to the total.
Where to buy
The Hive 12 needs a big room and a heavy circuit
The Hive 12 is a 12 kW floor-standing heater with a huge open stone basket. HUUM makes it for large residential and commercial rooms that want serious thermal mass and heavy steam. At $2,848 it costs less than the Drop package, because the controller and stones are extra and a basket takes less engineering than a lantern.
The Hive needs a high-amperage 240V circuit and a room big enough to justify it. Put a 12 kW heater in a four-person sauna and you'll get a hot room with poor steam, since the elements cycle off before the stones are through. Our heater sizing guide walks through the math. At a rough kilowatt per 45 cubic feet, we put the Hive at something over 500 cubic feet.
Where to buy
HUUM HIVE 12 12kW Electric Sauna Heater. HUUM photography.
See the specifications and priceEvery HUUM needs a 240V circuit and a controller
The heater price leaves out the wiring on every model. Each HUUM needs a dedicated 240V circuit, hardwired to code by a licensed electrician, and the Hive needs heavier-gauge wiring than the other two.
The UKU controller comes with the Drop package and costs extra on the Cliff and the Hive, and without it the heater has no on switch. The Drop package includes the stones too. You'll buy them separately for the other two, and at 165 pounds for a full Cliff, that's no small line on the invoice.
The running cost stays ordinary, because the extra stone doesn't add to it. A 9 kW HUUM drawing power through the working part of a session costs about what our running-cost calculator shows for any 9 kW heater.
Which HUUM should you buy?
Our pick for a two-to-four person room is the Drop 6, which gives you the best steam a small heater can make at a complete package price. The Cliff 9 fits a four-to-six person room or any room where clearance is the constraint. Save the Hive 12 for a big room and nothing smaller.
At the same wattage, a Harvia Cilindro costs less than a HUUM, and it's a first-rate heater. The extra money for a HUUM buys more stone and a heater that looks like furniture. Either one needs the same electrician, so match the heater to the room's volume before you choose on looks.
Where to buy
Common questions
- What size sauna does the HUUM Drop 6 heat?
- The HUUM Drop 6 heats a small to mid-size home sauna for roughly two to four people. Size it by room volume at about a kilowatt per 45 cubic feet, and lean toward a bigger heater if the room is outdoors or has a lot of glass. Its advantage is 121 pounds of stone at 6 kW, which gives a small room steam it usually can't get.
- Does a HUUM heater come with a controller?
- Only the Drop 6 package does. Sauna Kit Co sells the HUUM Drop 6 with the UKU Wi-Fi controller and the stones. The Cliff 9 and the Hive 12 come as the heater alone, and no HUUM runs without a controller, so price one in for those two.
- HUUM Cliff 9 or Harvia Cilindro: which is better?
- Pick the Harvia Cilindro on price, since it costs less at similar wattage. The HUUM Cliff 9 wins on clearance and stone mass. It carries up to 165 pounds of stone and needs smaller safety clearances, and HUUM says its internal air tunnel speeds heat-up by about a quarter. Both wrap far more stone around the elements than a box heater, so both store more heat per ladle.
- What electrical does a HUUM heater need?
- Every HUUM heater needs a dedicated, hardwired 240V circuit installed to code by a licensed electrician. The 12 kW Hive needs a higher-amperage circuit than the Drop or the Cliff, and no HUUM model is a plug-in appliance.
- Where can you buy HUUM heaters in North America?
- You'll find HUUM heaters at dealers, since HUUM doesn't sell direct. Sauna Kit Co carries the Drop, the Cliff and the Hive, and Select Saunas and Sun Valley Saunas stock HUUM alongside Harvia. Our product pages link to the current price at the dealer we track.
Sources
- 1.NFPA 70: National Electrical Code (NEC). National Fire Protection Association, 2023.
- 2.Electric Power Monthly: Average Price of Electricity to Ultimate Customers. U.S. Energy Information Administration, 2025.
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