HUUM CORE BK/ST CORE Series Sauna Heater, Customizable Exterior, Up to 10.5kW
The HUUM CORE BK/ST is a customizable-exterior electric sauna heater, available in 6.5kW, 9kW, and 10.5kW output configurations. It is the only CORE variant that arrives without exterior side cladding panels - the heater unit ships with a black or stainless top inlay cap and a bare stainless steel structural frame, leaving the side surfaces open for the owner to apply their own custom material: ceramic tile, natural stone, glass, or wood panels cut to fit. BK/ST stands for Black (top inlay) / Stainless (structural frame). Control unit and sauna stones (2 boxes) are sold separately. This listing is for buyers who want to build a fully bespoke sauna heater exterior - a heater that is an extension of the sauna room's specific material design rather than a choice between predetermined HUUM finish options.
The customizable CORE - bare frame, owner-applied exterior
Every other CORE variant - Black, Alder, Thermo-Aspen, Aspen - ships with HUUM-supplied exterior panels already applied to the stainless frame. The BK/ST ships without these side panels, exposing the structural stainless frame and the stone basket. The frame is engineered to accept tile, stone, glass, or wood panels applied by the owner or a contractor to cover the exposed side surfaces. This is not a visible-frame heater to be used as-is - it is a substrate for custom cladding. The black top inlay cap covers the top face of the heater; the sides are the owner's design canvas. For sauna rooms with continuous tile work, matching stone walls, custom millwork, or any specific material that no HUUM-supplied wood or black finish can match, the CORE BK/ST is the starting point. The open stone basket and the CORE heater performance remain identical to the other CORE variants - only the exterior treatment is left to the owner.
Three output levels - select at checkout
The CORE BK/ST is available in three output configurations, selectable at checkout. 6.5kW covers rooms from 177 to 318 cubic feet. 9kW covers rooms from 283 to 460 cubic feet. 10.5kW covers rooms from 354 to 566 cubic feet. The output selected determines the room coverage, electrical specification, and whether a UKU Extension Box is required for the control connection. Confirm the correct output for the specific sauna room using the Size Your Sauna document below before selecting at checkout. A compatible UKU control unit (Local Black or WiFi) is required for all output levels and sold separately at BathingBrands.
Small footprint, bench-embeddable, minimal safety distances
The CORE heater body is compact relative to its stone capacity - the open basket design keeps the footprint small while maintaining a substantial stone load. Minimal required safety distances from surrounding surfaces make the CORE BK/ST one of the most flexibly positioned sauna heaters available: it can be installed against walls, in corners, or embedded within the sauna bench structure. Bench embedding is a particularly natural application for the BK/ST - when the heater is set into the bench and clad with the same tile or stone as the surrounding bench surface, the result is a heater that is visually integrated into the bench rather than a separate object on the sauna floor.
Customizable-exterior sauna heater - arrives without side cladding panels for owner-applied tile, stone, glass, or wood exterior. Black top inlay / Stainless frame (BK/ST). Available in 6.5kW (177-318 cu ft), 9kW (283-460 cu ft), or 10.5kW (354-566 cu ft) - select at checkout. Open stainless stone basket. Small footprint - minimal safety distances - bench-embeddable. Required: UKU control (sold separately); 2 boxes sauna stones (sold separately). 3-year warranty (private use). SGS Listed. Made in Estonia by HUUM.
Customizable exterior - no side panels supplied Apply your own tile, stone, glass, or wood Black top inlay / Stainless frame 6.5kW, 9kW, or 10.5kW - select at checkout 177 to 566 cu ft depending on output Open stainless stone basket Small footprint - minimal safety distances Bench-embeddable UKU control sold separately 2 boxes stones sold separately 3-year warranty (private use) SGS Listed - made in Estonia
Specifications
Output options - select at checkout
| 6.5 kW |
177 to 318 cu ft |
| 9 kW |
283 to 460 cu ft |
| 10.5 kW |
354 to 566 cu ft |
| Voltage |
240V / 1-phase or 3-phase |
| Certification |
SGS Listed |
Stones and control
| Stones included |
No - 2 boxes sold separately |
| Stone specification |
See Stone Requirements document below |
| Control included |
No - UKU Local Black or WiFi sold separately |
| Room coverage |
Determined by output selected at checkout |
Design and installation
| Top inlay finish |
Black (standard) or other options - select at checkout |
| Structural frame |
Stainless steel |
| Side panels |
Not supplied - owner applies tile, stone, glass, or wood |
| Stone basket |
Open stainless steel |
| Safety distances |
Minimal - confirm in IOM for output selected |
| Bench-embedding |
Yes - bench installation supported |
| Origin |
Made in Estonia by HUUM |
CORE variant comparison
| CORE Black |
Painted black side panels - supplied by HUUM |
| CORE Alder |
Natural alder wood side panels - supplied by HUUM |
| CORE Thermo-Aspen |
Thermo-aspen wood side panels - supplied by HUUM |
| CORE Aspen |
Natural aspen wood side panels - supplied by HUUM |
| CORE BK/ST (this) |
No side panels - owner applies custom material |
Warranty
| Warranty period |
3 years (private use) |
| SKU |
H1013012 |
What's included
HUUM CORE BK/ST sauna heater - stainless frame, black top inlay, no side panels
Installation and operation manual
Required (not included): UKU control unit (Local Black or WiFi, sold separately); 2 boxes sauna stones (sold separately - see Stone Requirements); custom side panel material (tile, stone, glass, or wood - sourced and applied by owner). A licensed electrician is required. Do not connect to a GFI/GFCI breaker.
Why the HUUM CORE BK/ST stands out
Fully customizable exterior - your material, your design
Every other CORE variant ships with HUUM-determined exterior panels. The BK/ST ships with the structural frame and open basket exposed, ready for the owner to apply any flat panel material: the same tile as the sauna floor, the same stone as the wall cladding, a custom glass panel, or any wood species and cut the owner specifies. The result is a heater that is materially continuous with the surrounding room rather than a separate designed object within it.
Bench-embeddable - the most integrated install option
The CORE BK/ST is designed with bench embedding explicitly supported. When the heater is set into the bench structure and clad with the same tile or stone as the surrounding bench surface, it becomes part of the bench - invisible as a separate element from a distance. This is the most architecturally integrated possible heater installation, achievable with the CORE BK/ST's bare frame and minimal safety distances.
Minimal safety distances - flexible placement
The CORE heater body has minimal required safety distances from surrounding surfaces across all output levels - one of the tightest clearance specifications of any HUUM heater. Combined with the small footprint, this gives designers and installers maximum flexibility in placement: wall positions, corner placements, bench integrations, and alcove installations that other heaters' larger clearance requirements would rule out.
Three output levels - room-matched at checkout
6.5kW (177-318 cu ft), 9kW (283-460 cu ft), and 10.5kW (354-566 cu ft) are all available in the same BK/ST frame. The heater body is the same across all three - only the internal element configuration changes. Select the output at checkout based on the room volume calculated using the Size Your Sauna document below.
Open stone basket - same CORE performance
The CORE BK/ST uses the same open stainless steel stone basket as all other CORE variants - the stones are visible through the basket structure on all sides, direct stone-to-element contact throughout the load for even heat distribution, and water ladled onto the stones produces the same soft, consistent steam as any other CORE model. The customizable exterior does not change the heater's performance characteristics.
UKU WiFi compatible - remote preheat
Like all CORE heaters, the BK/ST is compatible with UKU Local Black (on-site digital control) and UKU WiFi (HUUM app remote preheat and scheduling on iOS and Android). Both are sold separately at BathingBrands. For a custom-built sauna room where design attention has gone into every material detail, the UKU WiFi adds the convenience of starting the carefully designed sauna environment from anywhere before arriving.
About HUUM
Made in Estonia - SGS Listed
HUUM CORE BK/ST. Customizable exterior. Up to 10.5kW. Bare frame - owner applies tile, stone, glass, or wood.
HUUM is an Estonian sauna heater company. The CORE BK/ST is the only CORE variant that arrives without exterior side panels - the stainless structural frame and open stone basket are left exposed for the owner to clad with any flat material: tile, stone, glass, or wood. Available in 6.5kW, 9kW, and 10.5kW (select at checkout). UKU control (Local Black or WiFi) and 2 boxes of sauna stones are required and sold separately. Bench-embeddable. Minimal safety distances. 3-year warranty (private use). We are an authorized HUUM dealer.
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No side panels supplied - owner applies tile, stone, glass, or wood
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6.5kW, 9kW, or 10.5kW - select at checkout (177-566 cu ft range)
- Bench-embeddable, minimal safety distances
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UKU Local Black or WiFi compatible - both sold separately
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3-year warranty (private use) - SGS Listed - made in Estonia
Manuals and Documents
Warranty
3-year limited warranty (private use)
The HUUM CORE BK/ST is covered by HUUM's 3-year limited warranty from the date of purchase for private use. The warranty covers defects in manufacturing and materials in the supplied heater components under normal use conditions. The warranty does not cover the owner-applied exterior cladding material, damage caused by improper installation or cladding application, use of incorrect or non-approved stones, operating 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 a GFI/GFCI breaker. Proof of purchase from an authorized HUUM dealer is required for warranty claims. We are an authorized HUUM dealer.
