HUUM CORE Thermo-Aspen Pkg CORE Series Sauna Heater Package, Thermo-Aspen Wood Exterior, Up to 10.5kW
The HUUM CORE Thermo-Aspen Package is the premium wood version of the CORE - the same stainless steel frame and full CORE performance as the Black, BK/ST, and Alder, with pre-fitted thermo-aspen wood side panels that ship as part of the heater. Thermo-aspen is aspen wood that has been heat-treated at high temperature in an oxygen-reduced environment. This thermal modification process alters the wood at a cellular level: it darkens the tone from aspen's natural pale cream to a warm rich brown, substantially increases dimensional stability under humidity cycling, reduces moisture absorption, and extends the wood's durability in high-heat, high-humidity environments such as a sauna. The result is a wood that looks more like aged hardwood or teak than fresh aspen, ages more gracefully in sauna conditions, and is more resistant to the warping and checking that untreated wood can develop over years of repeated heating and cooling cycles. The package includes the CORE Thermo-Aspen heater, UKU Local Black control, and sauna stones, in all three output levels selected at checkout.
Thermo-aspen vs standard alder - what thermal modification changes
Comparing the CORE Alder and CORE Thermo-Aspen is a comparison between two different wood species and processing methods. Alder is a pale-brown softwood used in Nordic sauna construction for generations - it is light, naturally stable enough for sauna use, and has a warm soft-grain appearance. Thermo-aspen starts as aspen (a lighter, finer-grained wood than alder) and is then heat-treated to change its properties. The thermal modification reduces the wood's equilibrium moisture content, which means it takes on and releases moisture more slowly during the heat cycles of sauna use - reducing dimensional movement and the surface checking that moisture cycling produces. The colour shifts to a richer warm brown that reads as more premium than either natural alder or natural aspen. Thermo-aspen is the more durable and visually refined of the two wood options on the CORE. Both are appropriate for sauna environments; thermo-aspen is the choice for buyers who want the longest-lasting wood finish with the deepest tone.
Pre-fitted panels - installs as a finished product
Like the CORE Alder, the Thermo-Aspen model arrives with the wood side panels already installed on the stainless steel frame by HUUM's factory. No fabrication work, no panel installation, no adhesive. The thermo-aspen panels cover the visible side faces of the heater while the stainless top rim with its selected inlay finish remains exposed. The combination of the rich dark-brown thermo-aspen wood and the stainless metal inlay produces a premium appearance that pairs well with thermally modified wood benches and walls, dark cedar, and any sauna interior where a refined, aged-wood aesthetic is the design goal. In lighter natural wood saunas, the darker thermo-aspen creates a deliberate material contrast rather than blending into the background.
Same CORE performance in every dimension
The CORE Thermo-Aspen is technically identical to the CORE Black, BK/ST, and Alder in every specification. Same three output levels (6.5kW, 9kW, 10.5kW), same 32.7"H x 15.2"W x 15.2"D dimensions, same 42-lb heater weight, same 66-lb stone capacity, same 2-inch safety clearance from combustible materials on all sides, same full bench embedding option, same 230°F maximum temperature, and same 3-year private warranty. The thermo-aspen panels are a surface treatment on the stainless frame - no technical specification changes between this and any other CORE package variant.
Complete floor-standing sauna heater package with pre-fitted thermo-aspen wood side panels 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 Thermo-Aspen heater (thermo-aspen panels factory fitted, inlay finish selected at checkout), UKU Local Black control, and sauna stones. Thermo-aspen: heat-treated aspen - richer dark-brown tone, enhanced moisture stability, longer-lasting than natural wood in sauna conditions. All three variants: 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 Pre-fitted thermo-aspen wood side panels Heat-treated - richer tone, enhanced durability Inlay finish selected at checkout No fabrication work required 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 |
Exterior and stones
| Side panels |
Thermo-aspen wood - pre-fitted at factory |
| Thermo-aspen treatment |
Heat-treated - darker tone, enhanced moisture stability |
| Inlay finish |
Selected at checkout (Black default) |
| Top rim |
Stainless steel with inlay finish |
| Stone capacity |
66 lbs (30 kg) - all variants |
| Stone size |
5-10 cm (2-4") |
| Stones included |
Yes - 2 boxes included in package |
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 |
| Side panels |
Thermo-aspen wood - factory fitted |
| 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 Thermo-Aspen heater with pre-fitted thermo-aspen panels (output and inlay finish selected at checkout)
UKU Local Black control panel
Sauna stones - 2 boxes (66 lbs total)
Adjustable leveling legs (4)
Installation and operation manual
Optional upgrades: UKU WiFi control panel, UKU Glass panel. HUUM also offers CORE panels in alder and aspen as alternative wood finishes.
Why the HUUM CORE Thermo-Aspen Package stands out
Thermo-aspen - the premium wood option
Heat-treated aspen with a richer dark-brown tone than natural alder or aspen. Thermal modification reduces moisture absorption and dimensional movement in sauna conditions, making thermo-aspen more stable and longer-lasting than untreated wood over years of repeated heating and cooling cycles. The panels arrive pre-fitted - no fabrication work needed.
Darker tone for refined interiors
Thermo-aspen's warm rich brown reads as a premium material alongside thermally modified wood benches, dark cedar, and contemporary design palettes where natural light wood would look too soft. It is the wood choice for sauna rooms that call for a darker, more aged-wood aesthetic rather than the pale freshness of alder.
Enhanced moisture stability
The thermal modification process reduces the wood's equilibrium moisture content - it takes on and releases moisture more slowly during sauna heat cycles. This reduces the surface checking, warping, and cracking that untreated wood can develop over years of use in a high-humidity, high-temperature environment.
Same CORE performance as all other variants
Technically identical to the CORE Black, BK/ST, and Alder - same 32.7"H x 15.2"W x 15.2"D, same 66-lb stone capacity, same 2-inch safety clearance, same bench embedding option, same 230°F maximum temperature. The thermo-aspen panels are a surface finish on the stainless frame, not a structural change.
2" clearance and bench integration
The thermo-aspen wood panels do not increase the safety clearance requirement. Only 2 inches required from combustible materials on all sides. Full bench embedding permitted with the panels in place - the thermo-aspen surface at bench level creates a seamless wood material connection between the heater and bench structure.
Complete package - ready to install
Heater with thermo-aspen panels, UKU Local Black control, and 2 boxes of stones. The only remaining steps are selecting output and inlay finish at checkout, and the electrical connection by a licensed electrician. No wood sourcing, no panel installation, no custom fabrication.
About HUUM
Made in Estonia - award-winning design
HUUM CORE Thermo-Aspen. The CORE with the premium wood finish for refined sauna interiors.
HUUM is an Estonian sauna heater manufacturer. The CORE Thermo-Aspen is the premium wood version of the CORE series - the same stainless steel structure, CORE performance, and UKU control compatibility as every other CORE package, with thermo-aspen wood side panels that arrive pre-fitted and require no installation work. Thermo-aspen is the most durable and visually refined wood option in the CORE range - darker, more stable in sauna conditions, and more distinctive than natural alder or standard aspen. For sauna builders who want a natural wood heater finish at the premium end of the wood spectrum, the Thermo-Aspen is the correct choice.
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Pre-fitted thermo-aspen panels - heat-treated, darker tone, enhanced moisture stability
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Identical specs to CORE Black - same output, dimensions, performance, warranty
- 2" safety clearance, bench embedding, 230°F max
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Complete package - UKU Local Black and 2 boxes stones included
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SGS Listed, made in Estonia - 3-year private / 1-year commercial warranty
Alder vs Thermo-Aspen - choosing the wood finish
CORE Alder vs CORE Thermo-Aspen - tone, durability, and design intent
Both the Alder and Thermo-Aspen packages arrive with factory-fitted wood panels, identical technical specifications, and the same complete package contents. The difference is the wood species and its treatment. Alder is a pale warm-brown, natural, and light-grained - it integrates softly into traditional Nordic sauna rooms with aspen or spruce walls and light bench surfaces. Thermo-aspen is a richer dark warm-brown, heat-treated for enhanced stability, and more visually distinctive - it pairs with thermally modified wood benches, dark cedar, and refined contemporary sauna interiors where a deeper wood tone is part of the design intent. Both are appropriate for sauna use; thermo-aspen is the more durable finish with the more premium appearance.
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 Thermo-Aspen 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 - including the thermo-aspen wood panels - 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. Proof of purchase from an authorized HUUM dealer is required for warranty claims. We are an authorized HUUM dealer.
