HUUM builds its sauna heaters in Estonia around one idea: put the stone in the open, in contact with the elements, instead of hiding it behind a steel skin. That is what gives these rooms their soft, wet heat, and it is why the DROP won a Red Dot design award. Five electric families from 4 to 18 kW, one UKU control that runs all of them from the wall or your phone, and olivine stone by the box.
Which heater fits your sauna?
A few questions about your room and the kind of heater you want. We'll show the ones rated for your room size and ceiling.
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The HUUM story
HUUM Sauna Heaters: Estonian Design, Built Around the Stone
HUUM is an Estonian manufacturer founded by Siim Nellis, a third generation sauna stove producer who set out to combine a sauna heater with modern design and modern control. The company works out of Tartu, an hour from Vorumaa, where the smoke sauna tradition was inscribed on the UNESCO Representative List of the Intangible Cultural Heritage of Humanity in 2014.
The DROP is the heater that made the name. It was developed in 2011 with the Estonian Academy of Arts, reached production in 2012, and won the Red Dot product design award in 2015. Its shape is not styling for its own sake: rounding the cage and cutting the metal surface lets the heater hold more stone for its size, which is where a sauna gets its soft heat and its steam.
Every HUUM electric heater follows the same idea. The stone sits in the open, in direct contact with the elements, rather than hidden behind a steel skin. You see the stone, you throw water onto the stone, and the room settles instead of swinging. The other half of the brand is the UKU control, which runs the heater from outside the room or from your phone.
The range
The HUUM Lineup: Five Electric Families and a Wood Stove Range
Every HUUM electric heater takes a separate control and its own quantity of stone. What separates the families is where the heater sits, how much stone it carries, and how it looks doing it.
DROP
The Red Dot winner, and the only HUUM heater light enough to ship by parcel. It hangs on the wall as an open cradle, in four sizes from 4.5 to 9 kW, all carrying the same 121.3 lb of stone. For rooms from 106 to 460 cubic feet.
CLIFF and CLIFF Mini
The slimmest heater HUUM makes: a 10.6 inch square column with removable ribs, so the stone packs tightly against the elements. CLIFF 6, 9 and 11 stand on the floor and hold 165 lb of stone. CLIFF Mini 4 is 6.3 inches deep and hangs on a wall bracket, for a room too small for anything else.
STEEL and STEEL Mini
A 12.6 inch square body, a little wider than the CLIFF, carrying twice the stone: 330 lb on STEEL 6, 9 and 11. STEEL Mini 4 hangs on a wall bracket like the CLIFF Mini. For rooms from 106 to 566 cubic feet.
HIVE and HIVE Mini
The round basket, and the heaviest stone load HUUM makes: 330 lb on the Mini and 528 lb on the full size. HIVE 12, 15 and 18 are the models for a large or commercial room, and they run through the UKU extension box.
CORE
A square heater designed to be finished in the same timber as your room, or left black. Alder, aspen and thermo-aspen panels, with a black or stainless trim ring, in 6.5, 9 and 10.5 kW.
Wood stoves
HIVE Wood and HIVE Flow, for a sauna with no electrical supply or an owner who wants the fire. They hold European certification and no North American listing, so the local building department decides. Ask us before you plan one.
Sizing
What Size HUUM Sauna Heater Do I Need?
Sauna heaters are sized on room volume, not floor area, and HUUM publishes a range for every model. Get this right and the room reaches temperature in about an hour and holds it. Get it wrong in either direction and you either wait, or the heater satisfies its thermostat before the stone is charged and the steam comes thin.
Measure in cubic feet
Length times width times height, in feet. A 7 by 6 room with a 7 foot ceiling is 294 cubic feet, which is a 6 kW job.
Count the cold surfaces
HUUM's manuals say to add 3.3 cubic feet for every square foot of uninsulated brick, tile or glass wall. We count a full glass door the same way, and it is often enough to move you up a model. The result is your adjusted cubic feet.
Check your voltage
Every figure below is for 240 volts. On a 208 volt supply the same heater makes less power and covers a smaller room, so size from the 208 volt row instead.
Mind the ceiling
HUUM sets a minimum room height per family: 75 inches for the DROP, 77 for the HIVE, 80 for the CORE and 86.6 for the CLIFF and STEEL. It also asks for 44 to 51 inches between the top bench and the ceiling.
Swipe the table sideways on a phone.
| Adjusted room volume | Output | Circuit at 240 V | HUUM models |
|---|---|---|---|
| 106 to 177 cu. ft. | 4 kW | 20 A | CLIFF Mini 4, STEEL Mini 4 |
| 106 to 248 cu. ft. | 4.5 kW | 30 A | DROP 4 |
| 177 to 318 cu. ft. | 6 to 6.5 kW | 30 A | DROP 6, CLIFF 6, STEEL 6, HIVE Mini 6, CORE 6 |
| 248 to 389 cu. ft. | 7.5 kW | 40 A | DROP 7 |
| 283 to 460 cu. ft. | 9 kW | 50 A | DROP 9, CLIFF 9, STEEL 9, HIVE Mini 9, CORE 9 |
| 354 to 566 cu. ft. | 10.5 to 11 kW | 50 A | CLIFF 11, STEEL 11, HIVE Mini 11, CORE 11 |
| 424 to 989 cu. ft. | 12 to 18 kW | Two circuits | HIVE 12, HIVE 15, HIVE 18 |
Figures are HUUM's own, from its current US manuals. The circuit column is the manufacturer's minimum: sauna heating is a continuous load, so your electrician may size the breaker and conductors larger to meet the code your area has adopted.
Before you order
Every HUUM Heater Needs Two More Things
A HUUM heater is three purchases, and the two that catch people out are not optional extras. The heater will not run without them.
A UKU control
The UKU's control unit goes outside the hot room, and its manual sets out which panel finishes can be mounted inside. UKU Local runs the heater from the wall; UKU Wi-Fi adds the phone app, so the room is hot when you get home. Local and Wi-Fi come in black or thermo-ash wood, and the glass, mirror and gold panels are Wi-Fi only.
One exception worth knowing: the UKU main module handles up to 11 kW on its own, so the HIVE 12, 15 and 18 need the UKU extension box as well. Nothing else in the range does, whatever a dealer listing tells you.
Sauna stone, by the box
HUUM supplies olivine stone in 33 pound boxes, in two grades: 1 to 2 inches for the CLIFF and STEEL families, 2 to 4 inches for the DROP, HIVE and CORE. The heater sets the quantity, not the room.
A CORE takes 3 boxes. A DROP, a CLIFF Mini and a STEEL Mini take 4. A CLIFF takes 5, a STEEL or a HIVE Mini 10, and a HIVE 12, 15 or 18 takes 16. The heater may not be switched on until it is properly filled, and a sparsely filled stone bed is a fire hazard rather than a shortcut.
The difference
What Sets HUUM Apart From Other Sauna Heater Brands
Stone in the open
Most heaters hide their elements behind a steel skin. HUUM runs them through the stone, so water thrown on the stone meets hot rock across the whole face of the heater. It is why these rooms give a softer, wetter heat than the kilowatts suggest.
A heater you are happy to look at
The DROP holds a Red Dot award and the range has taken European Product Design awards since. In a small room the heater is furniture, and HUUM is one of the few brands that treats it that way.
One control across the range
The same UKU runs every HUUM heater, with the app included on the Wi-Fi version. Learn it once and it works whether you buy a DROP for a closet conversion or a HIVE 18 for a commercial room.
Listed for North America
SGS lists HUUM's electric heaters and the UKU Local and Wi-Fi controls for the United States and Canada. The certificate number is on each product page, and we will send your inspector the listing record for your model.
Stone mass rather than kilowatts
A STEEL 6 carries 330 lb of stone against 121.3 lb in a DROP 6 at the same output, and the big HIVE models carry 528 lb. More mass means the room rides out the door opening and holds its temperature through a session with several people.
Sizes that actually cover the range
From a 106 cubic foot closet conversion to a 989 cubic foot commercial room, on the same design language and the same control.
Where to start
Which HUUM Heater Suits Which Room
DROP 6, 6kW
Best for the common two to four person home sauna, 177 to 318 cubic feet. Hangs on the wall, so it takes no floor, and runs on the same 30 amp circuit as the 4.5 kW.
See electric heatersSTEEL 9, 9kW
Best when you want stone mass on a small footprint: 330 lb of it in a 12.6 inch square body, for rooms to 460 cubic feet.
Compare sauna heatersCORE 9, 9kW
Best when the heater has to disappear into the room. Finished in alder, aspen or thermo-aspen to match your benches, or left black.
Use the heater finderHIVE 12, 12kW
Best for a large or commercial room, 424 to 636 cubic feet, with 528 lb of stone to ride out group after group. Needs two circuits and the UKU extension box.
Read the buyers guideElectrical and installation
What a HUUM Heater Asks of Your Electrician
Every HUUM electric heater is hardwired by a licensed electrician on its own dedicated circuit, or on two of them for the HIVE 12, 15 and 18, and the control is wired in with it. The DROP, CLIFF, STEEL and HIVE manuals call for cable meeting UL 62 in the United States or CSA 49 in Canada, crimped cable ends, no cable with non heat resistant PVC insulation, and any junction box inside the sauna waterproof and low on the wall. The CORE is wired to the National Electrical Code, which is the condition SGS records against its listing.
HUUM recommends connecting its heaters without a GFCI breaker. An outdoor sauna at a home falls inside the current requirement for ground fault protection on outdoor circuits at these ratings, so expect it there, while an indoor hardwired heater usually is not caught. Where the manual and the adopted code disagree, the code and your inspector decide.
Professional installation is a warranty condition. HUUM can ask for proof that a licensed electrician installed and connected the heater, so keep the invoice with your receipt. The room itself also has to be built for a sauna, with an insulated shell, a vapor barrier and supply and exhaust vents.
A guard is a code item rather than an upsell: the residential code asks for sauna heaters to be protected from accidental contact by a guard of a material with low thermal conductivity, such as wood, without blocking the heat. HUUM sells a rail for the DROP, CLIFF, STEEL, HIVE and HIVE Mini; around a CORE the guard is built rather than bought. Either way the heater's clearances have to be kept to the railing itself.
Buying from us
Delivery, Warranty and Returns on HUUM
How it arrives
The DROP ships as a parcel and needs nobody home. The floor standing heaters and the wood stoves come palletized by freight, by appointment, to the curb. Stone travels in its own boxes. Full details on our HUUM shipping policy.
Warranty
Three years in a private sauna, one year in a commercial one, with elements, sensors and stone excluded. We file the claim for you rather than sending you to Estonia. The full manufacturer text is on our HUUM warranty policy.
Returns
Thirty days from purchase on a new, uninstalled heater, with no percentage restocking fee. See the HUUM return policy for the conditions and who pays the freight.
Questions answered
HUUM Sauna Heaters: Questions Answered
Where are HUUM sauna heaters made?
HUUM is an Estonian company, founded by Siim Nellis, a third generation sauna stove producer, and its heaters are designed and built in Estonia. The DROP was developed in 2011 with the Estonian Academy of Arts and won the Red Dot product design award in 2015.
Are HUUM heaters listed for use in the United States?
Yes. SGS, which is on OSHA's list of nationally recognized testing laboratories, lists HUUM's electric heaters and the UKU Local and UKU Wi-Fi controls for the United States and Canada. The certificate number for each model is on its product page and we will send your inspector the listing record. HUUM's wood stoves hold European certification only, with no North American listing, so a local building department decides on those.
Do I need a control with a HUUM heater?
Yes, and it is a separate purchase. Every HUUM electric heater is run from a certified control mounted outside the hot room, and HUUM's matched control is the UKU, in Local or Wi-Fi form. A heater in a public sauna also has to have a timer.
Does a HUUM heater come with stones?
No. Stone is ordered by the box, and the heater sets the quantity: 3 boxes for a CORE, 4 for a DROP, 5 for a CLIFF, 10 for a STEEL or HIVE Mini, and 16 for a HIVE 12, 15 or 18. HUUM supplies olivine stone in 33 pound boxes in two grades, and the heater may not be switched on before it is properly filled.
What size HUUM heater do I need?
Measure the room in cubic feet, then add 3.3 cubic feet for every square foot of uninsulated brick, tile or glass wall, which is HUUM's rule, and count a full glass door the same way. Match that adjusted figure to the model's published range: 4 kW covers 106 to 177 cubic feet and 18 kW covers 636 to 989. If your supply is 208 volts rather than 240, size from the 208 volt figures instead, because the same heater makes less power.
What is the UKU extension box, and do I need one?
It is an extra module for heaters above 11 kW, which in this range means the HIVE 12, HIVE 15 and HIVE 18. Every other HUUM heater runs from the UKU's main module on its own. Dealer listings quote several different thresholds for it, which is where the confusion comes from.
Can I install a HUUM heater myself?
You can hang or place the heater and lay the stone. The electrical connection has to be made by a licensed electrician, and HUUM's warranty requires proof of professional installation, so keep the invoice.
What warranty comes with a HUUM heater?
Three years in a private sauna and one year in a commercial one, from the date of purchase, with spare parts covered for one year. Heating elements, all sensors, stones, accessories and a wood stove's glass and ash grate are excluded. HUUM counts it as commercial use if a registered business uses the product commercially, if a private owner uses it commercially, or if a private owner runs it for more than 1,500 hours in any 12 months.
How long does a HUUM sauna heater take to heat a room?
HUUM's manuals put it at about an hour in a properly insulated room with a correctly sized heater, with the stone reaching throwing temperature at about the same time as the air.
What does a HUUM heater cost to run?
Multiply the output by your electricity rate for the ceiling: a 6 kW heater at the US average residential price of 18.3 cents a kilowatt hour is about 1.10 dollars an hour at full draw. Once the room is at temperature the heater cycles rather than drawing full power, so a real session lands under that.
Not Sure Which HUUM Heater Fits Your Room?
Tell us the room dimensions and how the walls are built and we will walk you through HUUM's own figures for output, circuit and stone before you order.