HUUM HIVE Flow Mini Wood-Burning Sauna Stove, 8.5kW
The HUUM HIVE Flow Mini is an 8.5kW wood-burning sauna stove for rooms from 212 to 494 cubic feet, designed around a patent-pending furnace construction that retains 75% of the heat from firewood inside the sauna - significantly more than conventional sauna stoves where much of the heat escapes through the chimney. The result is a stove that uses less firewood per session, produces dramatically lower emissions, and delivers steam that lasts up to 30 minutes after the fire is out. CO emissions are just 346 mg/m3 - compared to over 1,000 mg/m3 in comparable stoves - and particulate matter output is only 25 mg/m3, the lowest in its output category. Safety distances from combustible materials are just 150mm (5.9") all sides, achieved through the Flow's unique furnace design rather than requiring a protective sheath. The stainless steel body (5mm thick top panels, 3mm sides) holds 231 lbs (105 kg) of sauna stones (7 boxes, sold separately), and the large glass door provides a view of the flames from inside the sauna room. Top or back chimney connection. Max firewood length 11.8" (300mm). BImSchV certified and CPR certified. 5-year limited warranty. Designed, engineered, and made in Estonia by HUUM.
Patent-pending Flow furnace - 75% heat retention, 4 sessions from 3 loads of wood
The defining feature of the HIVE Flow Mini is its patent-pending furnace construction. Air flows inside the heater in a unique pattern that allows 75% of the heat generated from burning wood to directly heat the sauna rather than escaping through the chimney. HUUM's own description of the practical effect is precise: you can enjoy four sessions with the same amount of wood that would typically provide three sauna sessions. This is not a marginal efficiency gain - it is a 33% increase in sessions per unit of firewood. The Flow design also dramatically reduces emissions as a byproduct of the more complete combustion: CO output is 346 mg/m3 against over 1,000 mg/m3 in comparable stoves, and particulate matter output of 25 mg/m3 is the lowest in its category. The BImSchV certification - the rigorous German clean combustion standard - confirms that the HIVE Flow Mini's emissions performance is independently verified, not just claimed.
5.9" safety distances - ultra-compact clearances from combustible materials
The HIVE Flow Mini's patent-pending furnace construction also produces an exceptional safety clearance profile. The required distance from combustible materials is just 150mm (5.9") on all sides - compared to the 200-500mm required by conventional sauna stoves of the same output class. HUUM attributes this directly to the unique construction: thanks to its unique patent-pending construction, the HIVE Flow stove has safety distances from combustible materials of just 150mm, compared to the usual 200-500mm. For a sauna room in the 212-494 cu ft range where every inch of space around the stove impacts bench layout flexibility, the HIVE Flow Mini's tight clearances directly increase the usable area of the sauna room without requiring any additional protective sheath or shield.
231 lbs of stones - steam lasts up to 30 minutes after the fire is out
The HIVE Flow Mini holds 231 lbs (105 kg) of sauna stones in an open stone cage above the furnace. The large exposed stone surface and the efficient heat transfer of the Flow furnace charge the stone mass thoroughly during the fire. HUUM's own description of the steam quality is direct: prolonged heat retention and steam that lasts up to 30 minutes after the fire is out. For a small to medium home sauna where the session continues after the fire burns down naturally, the stone thermal mass combined with the 75% heat retention of the Flow furnace means the sauna holds its temperature and steam quality well beyond what the fire itself produces. Rounded sauna stones 5-10 cm in diameter are recommended for milder steam. The large glass door allows the fire to be visible throughout the session. Top or back chimney connection accommodates different installation configurations.
8.5kW wood-burning sauna stove for rooms from 212 to 494 cubic feet. HIVE Flow Mini - patent-pending furnace design retains 75% of heat in sauna (vs typical 50%). Four sessions from the wood that typically gives three. CO emissions: 346 mg/m3 (vs 1,000+ in comparable stoves). Particulate matter: 25 mg/m3 - lowest in its category. Safety distances: 150mm (5.9") from combustible materials all sides - no protective sheath required. Steam lasts up to 30 minutes after fire is out. 231 lbs stones required (7 boxes, sold separately). 5mm top panels - 3mm sides. Large glass door. Top or back flue connection (115mm). Max firewood 11.8" (300mm). 6" adapter required for North America (sold separately). Dimensions: 17.7"W x 21.1"D x 34.8"H. BImSchV certified - CPR certified. Pallet delivery - scheduled freight required. 5-year limited warranty. Designed and made in Estonia by HUUM.
8.5 kW 212 to 494 cu ft HIVE Flow Mini - patent-pending furnace design 75% heat retention - 4 sessions from 3 wood loads CO: 346 mg/m3 (vs 1,000+ in comparable stoves) Particulate matter: 25 mg/m3 - lowest in category Safety: 150mm (5.9") all sides combustible - no sheath required 231 lbs stones required (7 boxes) Steam lasts up to 30 min after fire is out 5mm top panels - 3mm sides stainless steel Large glass door - fire view inside sauna Top or back flue - 115mm - 6" adapter required Max firewood 11.8" (300mm) 17.7"W x 21.1"D x 34.8"H BImSchV certified - CPR certified Pallet delivery required 5-year limited warranty Designed and made in Estonia by HUUM
Specifications
Performance
| Power output |
8.5 kW |
| Fuel type |
Wood - no electricity required |
| Room volume |
212 to 494 cu ft (6-14 m3) |
| Stone capacity |
231 lbs / 105 kg (7 boxes) - sold separately |
| Max firewood length |
11.8 in (300 mm) |
| Steam after fire out |
Up to 30 minutes |
Flow furnace efficiency and emissions
| Heat retention in sauna |
75% of firewood heat stays in sauna |
| Sessions per wood load |
4 sessions vs 3 for conventional stoves |
| CO emissions |
346 mg/m3 (vs 1,000+ mg/m3 in comparable stoves) |
| Particulate matter |
25 mg/m3 - lowest in its category |
| Furnace design |
Patent-pending - unique airflow pattern |
| Certifications |
BImSchV (German clean combustion) | CPR certified |
Safety distances (combustible materials)
| All sides |
5.9 in (150 mm) - achieved via Flow furnace design |
| Vs conventional stoves |
Conventional: 200-500 mm | HIVE Flow: 150 mm |
| Protective sheath required |
No - clearances achieved by furnace design alone |
Physical dimensions
| Width |
17.7 in (450 mm) |
| Depth |
21.1 in (537 mm) |
| Height |
34.8 in (884 mm) |
Construction
| Top panels |
5 mm thick stainless steel |
| Sides |
3 mm thick stainless steel |
| Glass door |
Large - fire view from inside sauna |
| Stone contact |
Direct contact between stones and heating surface |
| Ash management |
Ash drawer included |
| Cleaning access |
2 cleaning hatches included |
| Installation |
Floor-mounted, vertical orientation |
Flue and certifications
| Flue connection diameter |
115mm (4.5") |
| Flue connection position |
Top or back - selected during installation |
| North American adapter |
6" (155mm) adapter required - sold separately |
| Certifications |
BImSchV (German) | CPR certified |
| Origin |
Designed, engineered, and made in Estonia by HUUM |
| Warranty |
5-year limited warranty |
| Delivery |
Scheduled pallet freight - appointment required |
Optional accessories (sold separately)
| Protective cage |
HUUM Cage HSTV |
| Chimney - thru-ceiling |
HUUM Thru-Ceiling Chimney Kit |
| Chimney - thru-wall |
HUUM Thru-Wall Chimney Kit |
| Chimney - barrel |
HUUM Barrel Chimney Kit |
| Floor protection |
HUUM Protective Plate | HUUM Protective Bed |
| North American adapter |
6" (155mm) adapter - sold separately |
What's included
HUUM HIVE Flow Mini 8.5kW wood-burning sauna stove
Metal grate
Heat resistant glove
Splints
Metal fixing plates (x2)
Ash grate
Cleaning hatches (x2)
Ash drawer
Installation and operation manual
5-year limited warranty
Required (not included): 231 lbs sauna stones (7 boxes, rounded 5-10 cm diameter recommended); 6" North American flue adapter; chimney connection. Optional accessories (sold separately): HUUM Cage HSTV; HUUM Thru-Ceiling, Thru-Wall, or Barrel Chimney Kit; HUUM Protective Plate or Protective Bed. A licensed chimney professional is recommended for all flue installations.
Why the HUUM HIVE Flow Mini stands out
Patent-pending Flow furnace - 75% heat retention
The HIVE Flow Mini's patent-pending furnace creates a unique airflow pattern that keeps 75% of the heat generated from burning wood inside the sauna rather than letting it escape through the chimney. HUUM describes the practical result directly: you can enjoy four sessions with the same amount of wood that would typically provide three. This is a 33% improvement in sessions per unit of firewood - not a marginal gain. The Flow furnace design is the reason the HIVE Flow Mini produces dramatically lower emissions, achieves tighter safety clearances, and delivers steam that lasts longer after the fire goes out than a conventional stove of the same output class.
CO at 346 mg/m3 - 3x cleaner than comparable stoves
The HIVE Flow Mini's CO emissions of 346 mg/m3 compare to over 1,000 mg/m3 in comparable wood-burning sauna stoves. Particulate matter output of 25 mg/m3 is the lowest in its output category. These are not relative claims - they are measured values certified by BImSchV, the German clean combustion standard that is among the most rigorous emission standards applied to wood-burning appliances. The CPR certification confirms the stove's performance characteristics are formally declared. For buyers who want a wood-fired sauna experience but are conscious of wood combustion emissions - both for air quality inside the sauna building and environmental impact - the HIVE Flow Mini is the purpose-built specification.
5.9" safety distances - no protective sheath needed
Most wood-burning sauna stoves in the 8-9kW range require 200-500mm from combustible materials. The HIVE Flow Mini requires just 150mm (5.9") on all sides, achieved through the Flow furnace design rather than through a separate protective sheath. This distinction matters: a sheath is an additional purchase, an additional component to install, and adds visual bulk around the stove. The HIVE Flow Mini achieves tighter clearances without any of these additions. For a small sauna room in the 212-494 cu ft range where the stove is close to bench structures and wall panels, 5.9" all-round clearances give significantly more layout flexibility than even the most shielded conventional stoves.
231 lbs of stones - steam for up to 30 min after the fire
The HIVE Flow Mini's 231-lb stone load holds substantial thermal energy from the fire. HUUM describes the heat output as gentle and long-lasting - the high stone capacity relative to the stove's 8.5kW output ensures that the stones are the primary heat source during the session, not the fire itself. After the fire goes out, the charged stone mass continues delivering heat and steam for up to 30 minutes. For a home sauna where the session continues naturally past the fire's peak, the stone thermal mass sustains the experience without requiring another load of wood. Rounded sauna stones 5-10 cm in diameter are recommended by HUUM for milder, more pleasant steam quality.
Top or back flue - glass door - complete installation flexibility
The HIVE Flow Mini offers both top and back flue connection options, selected during installation to match the chimney routing - top connection for through-roof installations, back connection for through-wall configurations. This dual-connection flexibility accommodates the widest range of sauna room layouts without adapter plates or modifications. The large glass door on the front face provides a fire view from inside the sauna room throughout the session. Two cleaning hatches allow the interior combustion chambers to be accessed for maintenance without disassembling the stove. The ash drawer catches and holds ash between sessions, making ash removal clean and contained.
HIVE Flow Series - Mini and Mini LS configurations
The H1017012 is the standard interior-firebox configuration of the HIVE Flow Mini platform. The same 8.5kW Flow furnace is also available as the HIVE Flow Mini LS, which adds a firebox extension approximately 4.7 inches longer than the standard configuration, allowing wood to be loaded from an adjacent room or outdoors while the glass door faces the adjacent space for a fireplace view. Both configurations share the same patent-pending furnace, emissions performance, stone capacity, safety distances, and 5-year warranty. HUUM also offers the HIVE Flow (larger, for bigger rooms), the HIVE Wood Series (different stone-primary philosophy for standard combustion), and the HIVE Electric Series for electric sauna heating. Designed and made in Estonia. We are an authorized HUUM dealer.
About HUUM
Designed in Estonia - BImSchV Certified - HIVE Flow Series - Patent-Pending Furnace
HUUM HIVE Flow Mini. 8.5kW. 212-494 cu ft. 75% heat retention. CO 346 mg/m3. 5.9" clearances.
HUUM is an Estonian sauna heater company. The HIVE Flow Mini is 8.5kW with a patent-pending furnace that retains 75% of firewood heat inside the sauna, produces CO emissions of 346 mg/m3 (vs 1,000+ in comparable stoves), achieves 5.9" safety distances from combustible materials without a protective sheath, and delivers steam for up to 30 minutes after the fire is out. BImSchV certified. 231 lbs stones (7 boxes) and chimney connection required and sold separately. Pallet delivery. We are an authorized HUUM dealer.
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8.5kW wood-burning - 212-494 cu ft - patent-pending Flow furnace
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75% heat retention - 4 sessions per 3 wood loads - CO 346 mg/m3
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231 lbs stones required (7 boxes) - steam lasts up to 30 min after fire
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5.9" safety distances all sides - no protective sheath required
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BImSchV certified - top or back flue - 5-year warranty - made in Estonia
HIVE Flow Mini vs HIVE Wood LS 17 vs HUUM HIVE 12 - stove selection guide
HIVE Flow Mini vs HIVE Wood LS 17 vs HIVE 12 Electric - choosing the right HUUM sauna heater
Three HUUM heaters serve different room sizes, fuel types, and efficiency priorities. HUUM HIVE Flow Mini H1017012 (this listing): 8.5kW wood-burning, 212-494 cu ft, patent-pending Flow furnace (75% heat retention, CO 346 mg/m3, 5.9" clearances), 231 lbs stones (7 boxes), interior firebox, standard configuration. The most efficient and lowest-emission wood-burning option in the HUUM lineup. Right for small to medium home saunas where wood-firing efficiency, low emissions, and tight safety clearances are the priority. HUUM HIVE Wood LS 17 H1010012: 17kW wood-burning, 283-565 cu ft, LS firebox extension (exterior loading, glass door faces adjacent room), 287 lbs stones (9 boxes), stone-primary heat philosophy. Right for medium to large rooms where exterior wood loading and the HUUM stone-primary experience are the priority. HUUM HIVE 12 Electric: 12kW electric, 424-636 cu ft, UKU controller + extension box required, 550 lbs stones (approx. 17 boxes), beehive-inspired open cylindrical design, floor-standing. Right for large home and commercial saunas where electric heating with a sculptural stone column is the specification. Choose the HIVE Flow Mini for the 212-494 cu ft range where 8.5kW wood-firing efficiency, very low emissions, and the Flow furnace's 75% heat retention are the right combination.
Manuals and Documents
Warranty
5-year limited warranty
The HUUM HIVE Flow Mini carries HUUM's 5-year limited warranty from the date of purchase. The warranty covers defects in manufacturing and materials under normal use and maintenance conditions. The warranty does not cover damage caused by improper installation, failure to follow the installation and operating guidelines, use of incorrect or uncertified sauna stones (decorative stones in particular must not be used as they can break under heat), operating without the required stone load, or chimney-related damage from inadequate maintenance. A licensed chimney professional is recommended for all flue installation and regular chimney sweep maintenance. Proof of purchase from an authorized HUUM dealer is required for warranty claims. We are an authorized HUUM dealer.
