HUUM CORE BK/ST Pkg CORE Series Sauna Heater Package, Customizable Exterior, Up to 10.5kW
The HUUM CORE BK/ST Package is the customizable version of the CORE - the same stainless steel frame, identical performance specifications, and identical room coverage and electrical requirements as the CORE Black, but without the outer matte black metal casing. The BK/ST arrives with the stainless steel structure exposed and with an inlay finish (Black in this listing) as a starting point. The exposed frame accepts ceramic tiles, natural stone, glass panels, or wood cladding applied by the installer - making the CORE BK/ST the only heater in this catalog where the finished exterior appearance is entirely determined by the buyer and their sauna builder. The package includes the CORE BK/ST heater, UKU Local Black control, and sauna stones. All three output levels - 6.5kW, 9kW, and 10.5kW - are available at checkout and are physically identical in the unfinished state.
Customizable exterior - tile, stone, glass, or wood
The CORE BK/ST is designed to be clad. The stainless steel frame with its inlay finish is the foundation; what surrounds it is the builder's choice. Ceramic tile is the most common application - the 2-inch safety clearance means the tile can be applied directly to the stainless frame surface and sit within the required safety envelope. Natural stone cladding, whether granite, soapstone, or slate, produces a heater that reads as a natural stone pillar in the sauna room. Glass panels create a modern, translucent finish. Wood side panels in alder, aspen, or thermo-aspen are available from HUUM as ready-made accessories that snap into the frame, providing a natural wood finish without custom fabrication. Any material that can be safely used in a sauna environment at sustained temperatures can be used on the BK/ST frame - the only constraint is the safety distance maintained on all sides.
BK/ST vs Black - the only difference is the exterior
The CORE Black has a factory-applied matte black metal casing that ships as a finished product. The CORE BK/ST ships without that outer casing, with the stainless steel frame and inlay finish exposed. In every technical specification - output levels, dimensions, weight, stone capacity, safety distances, electrical requirements, UKU control compatibility, maximum temperature, and warranty - the BK/ST and Black are identical. The choice between them is a design decision: the Black is for buyers who want a finished product that installs without any cladding work; the BK/ST is for buyers who want the heater to match a specific material palette in the sauna room that a factory finish cannot achieve.
Same CORE performance - 2" clearance, bench embedding, 230°F max
All the performance characteristics that define the CORE carry through to the BK/ST. Only 2 inches of safety clearance from combustible materials on all sides - the most compact safety envelope of any floor-standing heater in this catalog - giving installation flexibility that larger heaters cannot match. Full bench embedding is permitted: the BK/ST can be embedded lengthwise into the sauna bench with the stone surface at bench level, making the heater part of the bench structure. The UKU control supports temperatures from 104°F to 230°F - a higher ceiling than the Harvia KIP (60-minute timer max ~175°F) or most other heaters. At 66 lbs stone capacity across all three output levels, the CORE produces the direct rock-to-element steam that the stone mass and the open top design enable.
Complete floor-standing sauna heater package with customizable exterior in three output levels: 6.5kW (177-318 cu ft), 9kW (283-460 cu ft), 10.5kW (354-566 cu ft) - select at checkout. Includes CORE BK/ST heater (unfinished exterior, inlay finish selected at checkout), UKU Local Black control, and sauna stones. Exterior accepts tile, stone, glass, or wood cladding by installer. HUUM wood side panels (alder, aspen, thermo-aspen) available separately. All three variants physically identical: 32.7"H x 15.2"W x 15.2"D, 42 lbs, 66 lb stone capacity. 2" safety clearance all sides. Full bench integration permitted. Max temperature 230°F. IPX4 rated. 240V / 1-phase. 6.5kW: 30A / 10 AWG. 9kW or 10.5kW: 50A / 8 AWG. Made in Estonia by HUUM. 3-year private / 1-year commercial warranty.
Complete package - control + stones included 6.5kW / 9kW / 10.5kW - select at checkout Customizable exterior - tile, stone, glass, or wood Inlay finish selected at checkout Wood side panels available separately 2" safety clearance all sides Full bench integration permitted 66 lb stone capacity Max temperature 230°F UKU Local Black control included Compact 15.2" x 15.2" square footprint IPX4 wet area rated Made in Estonia 3-year private warranty
Specifications
Output selection - choose at checkout
| 6.5kW |
177 to 318 cu ft | 30A breaker | 10 AWG |
| 9kW |
283 to 460 cu ft | 50A breaker | 8 AWG |
| 10.5kW |
354 to 566 cu ft | 50A breaker | 8 AWG |
| Voltage (all) |
240V / 1-phase / 60 Hz |
| Certification |
SGS Listed |
Dimensions and weight (all variants identical)
| Height |
32.7" (830 mm) |
| Width |
15.2" (385 mm) |
| Depth |
15.2" (385 mm) |
| Weight |
42 lbs (19 kg) |
| Mounting |
Floor-standing - sidewall, corner, or bench embedded |
Stones and exterior
| Stone capacity |
66 lbs (30 kg) - all variants |
| Stone size |
5-10 cm (2-4") |
| Stones included |
Yes - 2 boxes included in package |
| Exterior finish |
Unfinished frame + inlay finish (selected at checkout) |
| Cladding options |
Tile, stone, glass, wood - applied by installer |
| HUUM wood panels |
Alder, aspen, thermo-aspen - sold separately |
Safety distances (all variants identical)
| All sides - combustible materials |
2" (50 mm) |
| Ceiling clearance |
32.7" (830 mm) |
| Bench integration |
Permitted - full-length embedding in bench |
Control and performance
| Control included |
UKU Local Black |
| WiFi capability |
No - upgrade to UKU WiFi sold separately |
| Temperature range |
104°F to 230°F (40°C to 110°C) |
| IP rating |
IPX4 - wet area approved |
| HUUM app |
Compatible with UKU WiFi upgrade |
Construction and warranty
| Frame material |
Stainless steel with inlay finish |
| Outer casing |
None - customizable by installer |
| Private use warranty |
3 years (elements excluded) |
| Commercial warranty |
1 year (elements excluded) |
| Origin |
Designed and made in Estonia by HUUM |
What's included
HUUM CORE BK/ST heater - unfinished frame with inlay finish (output and inlay selected at checkout)
UKU Local Black control panel
Sauna stones - 2 boxes (66 lbs total)
Adjustable leveling legs (4)
Installation and operation manual
Cladding not included - applied by installer: Tile, stone, glass, or wood. HUUM wood side panels available separately: Alder, aspen, thermo-aspen. Optional upgrades: UKU WiFi control, UKU Glass panel.
Why the HUUM CORE BK/ST Package stands out
Fully customizable exterior
The BK/ST ships without an outer casing. Ceramic tile, natural stone, glass, or wood can be applied to the exposed stainless frame by the installer. HUUM wood side panels in alder, aspen, or thermo-aspen are available as ready-made accessories. The result is a heater whose exterior exactly matches the sauna room's material palette - something no factory-finished heater can offer.
Same CORE performance as the Black
Identical specs to the CORE Black in every technical dimension: same output levels, same dimensions (32.7"H x 15.2"W x 15.2"D), same 66-lb stone capacity, same 2-inch safety clearance, same 230°F maximum temperature, same bench embedding option, same UKU control compatibility. The exterior is the only thing that differs.
2" clearance - tile cladding within safety envelope
With only 2 inches of required safety clearance from combustible materials, tile cladding can be applied directly to the frame and sit within the safety envelope. A tiled CORE BK/ST reads as a tiled pillar in the sauna room - indistinguishable from a custom-built stone element unless the viewer knows it is a heater inside.
Bench integration with custom cladding
The BK/ST can be embedded lengthwise within the sauna bench, just like the CORE Black. With custom tile or stone cladding on a bench-embedded BK/ST, the heater becomes a seamless part of the bench structure - a stone or tile mass that produces heat and steam from within the bench, with no visible heater element in the room.
Three outputs - same unfinished frame
6.5kW, 9kW, and 10.5kW are all the same physical frame. Choose the largest output the electrical supply supports. A larger heater heats faster, runs at lower duty cycle, and places less thermal stress on elements. The unfinished exterior looks identical regardless of output level.
UKU ecosystem - upgradeable
The included UKU Local Black has no WiFi. The same wiring supports UKU WiFi (remote preheat and HUUM app), UKU Glass, and UKU Wood panels as future upgrades without rewiring. The full HUUM control ecosystem is accessible from the same connection architecture.
About HUUM
Made in Estonia - award-winning design
HUUM CORE BK/ST. The CORE for builders who want to finish the heater themselves.
HUUM is an Estonian sauna heater manufacturer. The CORE BK/ST is the blank canvas version of the CORE - the same stainless steel structure, performance, and UKU control compatibility as the CORE Black, shipped without the outer casing so the installer can apply any cladding that suits the sauna room. Tile, stone, glass, or wood - the BK/ST accepts all of them. For sauna builders and designers who want a heater that disappears into the room's material composition rather than standing apart from it, the BK/ST is the right choice. For buyers who want a finished product without any additional fabrication work, the CORE Black is the alternative.
-
Customizable exterior - tile, stone, glass, or wood applied by installer
-
Identical specs to CORE Black - same output, dimensions, performance, warranty
- 2" safety clearance, bench embedding, 230°F max
-
Complete package - UKU Local Black and 2 boxes stones included
-
SGS Listed, made in Estonia - 3-year private / 1-year commercial warranty
CORE Black vs CORE BK/ST
CORE Black vs CORE BK/ST - the only difference is the outer finish
Both packages include the same UKU Local Black control and sauna stones. Both are available in 6.5kW, 9kW, and 10.5kW. Both share identical dimensions, weight, stone capacity, safety distances, electrical requirements, and warranty. The CORE Black ships with a factory-applied matte black metal casing - it installs as a finished product. The CORE BK/ST ships without that casing, with the stainless frame and inlay finish exposed, ready for custom tile, stone, glass, or wood cladding by the installer. If the sauna room will be tiled, stone-clad, or built around a specific custom material, the BK/ST is the correct choice. If a clean factory-finished black heater is preferred, the CORE Black is the alternative.
A standard 2-pole breaker (30A for 6.5kW, 50A for 9kW and 10.5kW) and appropriate AWG wire are required. Do not connect to a GFI/GFCI breaker. A licensed electrician is required for all connections.
Manuals and Documents
Warranty
3-year private warranty / 1-year commercial warranty (elements excluded)
The HUUM CORE BK/ST is covered by a 3-year limited warranty for private (residential) use and a 1-year limited warranty for commercial use from the date of purchase. Heating elements are excluded from warranty coverage. The warranty covers defects in manufacturing and materials under normal use conditions. The warranty is void if: the heater is connected to a GFI/GFCI breaker, the buyer fails to follow the installation and operation manual, incorrect or insufficient stones are used, or the product is damaged by failure to follow instructions. Custom cladding applied by the installer must not obstruct the required safety clearances or the air movement required beneath the heater when bench-embedded. Proof of purchase from an authorized HUUM dealer is required for warranty claims. We are an authorized HUUM dealer.
