The HUUM HIVE 15STUX Package is a complete sauna heater package for large sauna rooms from 530 to 813 cubic feet, including the HIVE 15kW floor-standing heater, UKU sauna control with wood case (Local or WiFi - selected at checkout), UKU Extension Box, and 528 lbs of rounded olivine diabase sauna stones (16 boxes). The HIVE 15kW steps up from the 12kW with 25% more output for the same physical body and the same 528-lb stone capacity, covering the larger room range that the 12kW cannot serve. The key electrical difference from the HIVE 12: the 15kW requires dual 50A breakers and dual 8 AWG wire runs rather than the 12kW's dual 30A / 10 AWG - a heavier electrical specification that must be planned and confirmed before ordering.
HIVE 15 vs HIVE 12 - more output, heavier electrical, same body
All three HIVE models - 12kW, 15kW, and 18kW - share identical external body dimensions: 22" (560mm) diameter, 29.5" (750mm) height. The physical footprint in the sauna room, the 528-lb stone capacity, the air tunnel, and the floor-standing installation method are the same across all three. What differs is the output level and the corresponding electrical requirement. The HIVE 12 runs on dual 30A breakers with 10 AWG wire. The HIVE 15 requires dual 50A breakers with 8 AWG wire. The HIVE 18 also uses dual 50A / 8 AWG. For rooms from 530 to 813 cubic feet where the HIVE 12's 424-636 cu ft range is insufficient, the HIVE 15 is the correct step up - provided the electrical panel can supply two 50A circuit breaker slots and the electrician can run two 8 AWG wire circuits to the UKU Extension Box location.
530-813 cu ft - large residential and commercial sauna rooms
The 15kW range of 530-813 cu ft covers large residential sauna rooms, sauna cabins with multiple benches, and mid-size commercial installations in health clubs, day spas, and gyms. At 530 cubic feet, a sauna room is typically a dedicated structure rather than a converted interior room - a purpose-built sauna cabin, a detached sauna building, or a large home sauna room with two or more bench levels. At 813 cubic feet, the HIVE 15 is at the upper end of what a single 15kW heater can serve; rooms approaching this volume, or rooms with significant cold surfaces such as glass walls or tile floors, may require confirming the adjusted cubic footage before selecting between the 15kW and the 18kW. Use the HUUM heater calculator in the Size Your Sauna document below for guidance.
528 lbs of stone, air tunnel pre-installed - same as HIVE 12
The HIVE 15 carries the same 528-lb stone capacity as the HIVE 12 in the same beehive-inspired open cage. The air tunnel is pre-installed on the heater in this package, directing airflow more efficiently through the stone mass to speed up heating by approximately 25% and extend heating element life. The 16 boxes of rounded olivine diabase stones (2"-4", 5-10 cm) included in this package are the correct type and quantity for the HIVE 15. As with the HIVE 12, this package ships on a wooden pallet by freight and requires a scheduled delivery appointment.
Complete 15kW floor-standing sauna heater package for large rooms from 530 to 813 cubic feet. Includes HIVE 15kW heater, UKU control with wood case (Local or WiFi - select at checkout), UKU Extension Box (required for 15kW - included), and 528 lbs of rounded olivine diabase stones (16 boxes). Same beehive-inspired open cage body as HIVE 12 and 18 - 22" diameter x 29.5"H. Air tunnel pre-installed - 25% faster heating, extended element life. Dual 50A breakers + dual 8 AWG wire required (heavier than HIVE 12). 240V / 1-phase. Max 230°F. SGS Listed. Ships on wooden pallet - scheduled delivery. 5-year warranty (elements excluded). Made in Estonia by HUUM.
Complete package - control + ext box + 528 lbs stones 15 kW 530 to 813 cu ft Floor-standing - same body as HIVE 12 and 18 Beehive-inspired open cage design 528 lb stone capacity - 16 boxes included Air tunnel pre-installed - 25% faster heat-up UKU Extension Box included (X in model name) UKU Local w/Wood Case or UKU WiFi - select at checkout HUUM app - iOS and Android (WiFi variant) Dual 50A breakers - dual 8 AWG - 240V 1-phase Ships on wooden pallet - scheduled delivery SGS Listed - made in Estonia 5-year warranty (elements excluded)
Specifications
Electrical
| Power output |
15 kW |
| Voltage |
240V / 1-phase / 60 Hz |
| Total amperage draw |
62.5 A (31.25A per circuit) |
| Circuit breakers required |
Two separate 50A breakers (no GFI/GFCI) |
| Wire gauge |
Two runs of 8 AWG |
| UKU Extension Box |
Required - included in this package |
| Certification |
SGS Listed |
Room sizing and stones
| Room volume |
530 to 813 cu ft |
| Stone capacity |
528 lbs (16 boxes) |
| Stones included |
Yes - 16 boxes rounded olivine diabase |
| Stone size |
2" to 4" (5-10 cm) rounded |
| Max temperature |
230°F (110°C) |
Physical
| Diameter |
22" (560 mm) |
| Height |
29.5" (750 mm) |
| Construction |
Stainless steel open cage |
| Mounting |
Floor-standing (or bench-embedded) |
| Air tunnel |
Pre-installed - 25% faster heat-up, extended element life |
| Origin |
Made in Estonia by HUUM |
Control options - select at checkout
| UKU Local w/Wood Case |
Digital control with thermo-ash wood enclosure - on-site |
| UKU WiFi |
Adds HUUM app remote preheat and scheduling |
| App |
HUUM app - iOS and Android (WiFi variant) |
| UKU Extension Box |
Required and included |
HIVE series electrical comparison
| HIVE 12kW |
424-636 cu ft | Dual 30A | Dual 10 AWG |
| HIVE 15kW (this listing) |
530-813 cu ft | Dual 50A | Dual 8 AWG |
| HIVE 18kW |
636-955 cu ft | Dual 50A | Dual 8 AWG |
| Body dimensions |
Identical across all three HIVE models |
| Stone capacity |
528 lbs - identical across all three |
Delivery and warranty
| Delivery method |
Freight on wooden pallet - scheduled appointment |
| Warranty |
5 years (elements excluded) |
| Design inspiration |
Wild beehive - open cage form |
What's included
HUUM HIVE 15kW floor-standing sauna heater - stainless steel open cage
UKU sauna control with wood case (Local or WiFi - selected at checkout)
UKU Extension Box (required for 15kW - included)
Rounded olivine diabase sauna stones - 16 boxes (528 lbs)
Air tunnel (pre-installed on heater)
Installation and operation manual
Optional accessories (sold separately): HUUM HIVE safety railing (recommended), reflector panels (allow closer wall installation), HIVE embedding flange (for bench mounting). A licensed electrician is required for all electrical connections.
Why the HUUM HIVE 15STUX Package stands out
15kW for 530-813 cu ft - beyond the HIVE 12 range
The HIVE 15kW covers rooms that the HIVE 12 cannot - from 530 to 813 cubic feet. For large dedicated sauna buildings, multi-bench sauna rooms, and commercial installations where the 12kW's 636 cu ft ceiling is insufficient, the 15kW is the appropriate next step. The 25% output increase over the 12kW translates directly to faster heat-up times and effective coverage of larger room volumes.
Same body as HIVE 12 and 18 - no size difference
The HIVE 15 is physically identical to the HIVE 12 and 18: same 22" diameter, same 29.5" height, same open beehive cage, same 528-lb stone capacity, same floor-standing footprint. The output level changes with the number of heating elements inside the cage. The installation footprint and stone loading procedure are the same regardless of which HIVE model is selected.
528 lbs of stone - massive sustained thermal mass
The same 528-lb stone load as the HIVE 12 - now driven by 15kW of output. More output heating the same stone mass means faster heat-up to bathing temperature and greater capacity to sustain that temperature through extended sessions and back-to-back use with multiple bathers. The open cage airflow ensures all 528 lbs are heated evenly, producing soft, consistent steam from the full stone volume when water is ladled.
Air tunnel pre-installed - 25% faster, longer element life
The HIVE air tunnel is pre-installed in every HIVE package. It directs airflow more efficiently through the stone mass during the warm-up cycle, reducing heat-up time by approximately 25% and reducing thermal stress on the heating elements. For a 15kW heater covering rooms up to 813 cu ft, faster heat-up is a meaningful operational benefit - particularly for commercial installations where sauna turnaround time matters.
Dual 50A / 8 AWG - plan the electrical carefully
The HIVE 15 requires two separate 50A breakers and two 8 AWG wire runs - heavier than the HIVE 12's dual 30A / 10 AWG. Confirm panel capacity for two 50A slots before ordering. The UKU Extension Box (included) manages the dual-circuit connection to the single UKU control. All wiring must be completed by a licensed electrician. No GFI/GFCI breakers.
UKU WiFi - remote preheat for a large sauna
A 530-813 cu ft sauna room requires significant warm-up time at 15kW. Upgrading to UKU WiFi at checkout enables remote preheat via the HUUM app - start the sauna from anywhere and arrive to a room already at temperature. For commercial use where sessions are scheduled in advance, the WiFi variant with app scheduling is the operationally practical choice.
About HUUM
Made in Estonia - SGS Listed
HUUM HIVE 15STUX. 15kW. 530-813 cu ft. 528 lbs of stone. The complete mid-range HIVE package.
HUUM is an Estonian sauna heater company. The HIVE 15STUX Package steps up from the HIVE 12 with 25% more output in the same body for rooms from 530 to 813 cubic feet. The package includes every required component: the HIVE 15kW heater with pre-installed air tunnel, UKU control with wood case (Local or WiFi at checkout), UKU Extension Box, and 528 lbs of rounded olivine diabase stones in 16 boxes. Delivered on a wooden pallet via scheduled freight. A licensed electrician is required for the dual-circuit 50A / 8 AWG installation. We are an authorized HUUM dealer.
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Complete package - HIVE 15kW, UKU control w/wood case, UKU Ext Box, 528 lbs stones
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15kW, 530-813 cu ft - dual 50A breakers, dual 8 AWG, 240V/1PH
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Same 528 lb stone capacity as HIVE 12 and 18
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Air tunnel pre-installed - 25% faster heat-up, extended element life
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Pallet delivery, scheduled appointment - 5-year warranty (elements excluded)
HIVE 12 vs 15 vs 18 - choosing the right output
Which HIVE output level is correct - 12kW, 15kW, or 18kW?
All three HIVE models share identical body dimensions (22" diameter, 29.5"H), stone capacity (528 lbs), and installation method. The selection is based on room size and adjusted cubic footage. HIVE 12kW: 424-636 cu ft, dual 30A / 10 AWG. HIVE 15kW: 530-813 cu ft, dual 50A / 8 AWG. HIVE 18kW: 636-955 cu ft, dual 50A / 8 AWG. The 15 and 18 share the same electrical specification; the difference between them is output and room range. The 15kW overlaps with the 12kW from 530 to 636 cu ft: in this overlap zone, a well-insulated standard room may be adequately served by the 12kW at lower electrical cost, while a room with cold surfaces or high-frequency commercial use would benefit from the 15kW's additional output headroom. For rooms from 637 cu ft and above, the 15kW or 18kW is required. Use the HUUM heater calculator in the Size Your Sauna document below to verify the adjusted cubic footage of the specific sauna room before selecting the output level.
Licensed electrician required. No GFI/GFCI. HIVE safety railing recommended. Reflector panels and embedding flange sold separately. All three HIVE models deliver on wooden pallet with scheduled freight appointment.
Manuals and Documents
Warranty
5-year limited warranty (elements excluded)
The HUUM HIVE 15STUX Package is covered by HUUM's 5-year limited warranty from the date of purchase. The warranty covers defects in manufacturing and materials under normal use conditions. Heating elements are excluded from the 5-year coverage and carry their own separate warranty period. The warranty does not cover damage caused by improper installation, incorrect dual-circuit wiring, use of incorrect or non-approved stones, operating the heater without the required stone load, or failure to follow HUUM's installation and operating guidelines. A licensed electrician is required for all electrical connections. Do not connect to GFI/GFCI breakers. Proof of purchase from an authorized HUUM dealer is required. We are an authorized HUUM dealer.
