Harvia Legend 300DUO Legend Series Sauna Wood-Burning Stove/Fireplace Combo
The Harvia Legend 300DUO is a 23.5kW wood-burning sauna stove and fireplace combination for rooms from 529 to 1,059 cubic feet. The DUO configuration means the fire chamber extends through the sauna wall - wood is loaded from an adjacent room or from outdoors, never from inside the sauna. The cast-iron glass door faces outward into the adjacent room, creating a live fireplace view for the person outside while bathers inside the sauna receive the full 23.5kW heat output and the steam from 573 lbs of AC3020 stones. The door opening direction is reversible, set during installation to suit the room layout. The massive black steel frame holds the stones that define the Legend platform - enough thermal mass to keep the sauna bath going long after the fire has burned down. The split-air grate structure directs part of the combustion air to the upper fire chamber for cleaner, more efficient burning. Adjustable legs simplify levelling during installation. Flue connection: 115mm (4.5") European standard - a 6" North American adapter is required and sold separately. 573 lbs AC3020 stones (13 boxes, 10-15 cm) required and sold separately. Pallet delivery - scheduled freight appointment required. CE and EAC certified. Made in Finland by Harvia.
DUO configuration - sauna heat inside, fireplace view outside, one fire
The Legend 300DUO's defining feature is precisely described by Harvia: it is the right choice for people who want to conveniently heat their sauna from another room or outside the building. The fire chamber passes through the sauna wall so that the firebox opening and the cast-iron glass door face the adjacent room - a lounge, relaxation area, or exterior space. Wood is loaded, the fire is managed, and the flame is visible from outside the sauna at all times. Inside the sauna, bathers experience the full output of the 23.5kW stove: the warmth radiated by 573 lbs of heated stones, the dense steam from water thrown on that stone mass, and the undisturbed atmosphere of a sauna session that never requires the door to open for wood loading. The DUO creates two simultaneous experiences from a single fire - the traditional sauna inside, the living fireplace outside.
573 lbs of stones - heat stored deep in the stone mass
Like all Legend Series stoves, the 300DUO is built around stone mass as the primary heat source. At 573 lbs minimum, the stone load accumulates thermal energy throughout the fire and holds it long after the flames die down. The sauna temperature stays consistent, the steam quality remains dense, and the session continues without reloading. For a long group bathing session or an installation where tending the fire from outside is the preferred mode, the Legend 300DUO's stone mass means the heat is self-sustaining once the fire has run its course. The black steel frame that defines the visual character of the Legend Series exists primarily to hold and present this stone mass - it is the structural and thermal core of the stove.
Reversible door and split-air grate - installation flexibility and efficient combustion
The cast-iron glass door opening direction is reversible - set during installation to suit the access direction from the adjacent room. This means the door swing can be optimised for whichever side the firebox faces without requiring a specific handed configuration at the time of purchase. The split-air grate structure routes a portion of the combustion air to the upper fire chamber, supporting more complete combustion and reducing smoke and creosote output. Harvia specifically credits this grate design with extending the stove's service life - relevant for a stove of this mass and investment that is expected to deliver decades of service. Top or rear flue connection options accommodate chimney routing on either axis. A licensed chimney professional is recommended for all flue installations.
23.5kW wood-burning sauna stove and fireplace combo for rooms from 529 to 1,059 cubic feet. DUO exterior feed - fire chamber extends through sauna wall, wood loaded from adjacent room or outdoors. Cast-iron glass door faces outward - fireplace view from adjacent room while sauna bathers enjoy heat inside. Reversible door direction. No electricity required. Black steel frame - 573 lbs AC3020 stones required (13 boxes, 10-15 cm, sold separately). Split-air grate for cleaner, efficient combustion. Safety distances: front 27.56", sides 7.87", back 9.84" (combustible). Top or rear flue connection. 115mm flue - 6" adapter required for North America (sold separately). Optional: WL200 protective sheath, WL300 smoke pipe guard, WP250LD pipe-mounted water heater. Pallet delivery - scheduled freight required. 2-year warranty (consumer). CE and EAC certified. Made in Finland by Harvia.
23.5 kW 529 to 1,059 cu ft DUO - exterior feed through sauna wall Wood loaded from adjacent room or outdoors Cast-iron glass door faces outward - fireplace view Reversible door direction Wood-burning - no electricity required Black steel frame - 573 lb stone mass 573 lbs AC3020 stones required (13 boxes, 10-15 cm) Split-air grate - cleaner, efficient combustion Safety: front 27.56", sides 7.87", back 9.84" Top or rear flue connection 115mm flue - 6" adapter required for North America Adjustable legs WL200 protective sheath compatible Pallet delivery required 2-year warranty (consumer) CE and EAC certified - made in Finland
⚠️ 573 lbs AC3020 stones (13 boxes, 10-15 cm) required - not included. 6" North American flue adapter required - not included. Pallet delivery. Stones and the 6" adapter must be purchased separately before the stove can be operated. An additional box of stones is recommended to allow selection of best-fitting stones. This stove ships by scheduled pallet freight - a delivery appointment is required. At 223 lbs gross packaged weight, plan for on-site assistance to move from the delivery point to the installation position. A licensed chimney professional is recommended for all flue installations. The wall penetration for the DUO fire chamber requires correct preparation per the installation manual before delivery.
ℹ️ Legend 300DUO WKLE36DUOM vs Legend 300 WKLE36M - DUO exterior feed vs standard interior feed, same platform. Legend 300 WKLE36M: interior feed - firebox door faces into the sauna room, wood loaded from inside the sauna during the session, steel-framed glass door provides fire view for bathers. Legend 300DUO WKLE36DUOM (this listing): exterior feed - fire chamber extends through the sauna wall, wood loaded from an adjacent room or outdoors, cast-iron glass door faces the adjacent room for a live fireplace view, bathers in the sauna are completely undisturbed. Both share identical output (23.5kW), room range, stone requirement (573 lbs, 13 boxes AC3020), and Legend platform. Choose the Legend 300 for interior-feed simplicity. Choose the Legend 300DUO for exterior wood loading, undisturbed sauna sessions, and the dual-room fireplace experience.
Specifications
Performance
| Power output |
23.5 kW |
| Fuel type |
Wood - no electricity required |
| Room volume |
529 to 1,059 cu ft (15-30 m³) |
| Stone capacity |
573 lbs / 260 kg (13 boxes AC3020, 10-15 cm) - sold separately |
| Stone size |
Ø 10-15 cm (AC3020) |
DUO exterior feed
| Firebox access |
From outside the sauna room via wall extension |
| Glass door faces |
Adjacent room - fireplace view from outside sauna |
| Door direction |
Reversible - set during installation |
| Dual-room effect |
Sauna heat inside + fireplace view outside simultaneously |
Safety distances (combustible materials)
| Front |
27.56 in (700 mm) |
| Sides (left and right) |
7.87 in (200 mm) |
| Back |
9.84 in (250 mm) |
| Ceiling clearance |
3.28 ft (1,000 mm) above heater top |
| Side / back (non-combustible) |
3.94 in (100 mm) |
| Minimum room ceiling height |
6.56 ft (2,000 mm) |
Physical dimensions
| Width |
23.62 in (600 mm) |
| Depth |
30.71 in (780 mm) - extended for DUO wall penetration |
| Height |
3.41 ft (1,040 mm) |
| Gross weight (packaged) |
223.3 lbs (101.3 kg) |
Flue and installation
| Flue connection diameter |
115mm (4.5") - standard European |
| Flue connection position |
Top or rear - selected during installation |
| North American adapter |
6" (155mm) adapter required - sold separately |
| Legs |
Adjustable |
| Delivery |
Scheduled pallet freight - appointment required |
Legend 300DUO vs Legend 300 comparison
| Feed direction |
DUO: Exterior (through wall) | Legend 300: Interior (sauna room) |
| Glass door faces |
DUO: Adjacent room | Legend 300: Into sauna room |
| Output, room range, stones |
Identical - 23.5kW, 529-1059 / 494-989 cu ft, 573 lbs (13 boxes) |
| DUO depth vs Legend 300 depth |
30.71 in vs 25.98 in - longer for wall extension |
Optional accessories (sold separately)
| North American flue adapter |
Harvia WZ115155 (6" / 155mm) |
| Protective sheath |
Harvia WL200 (1-3 panels, reduces clearances) |
| Smoke pipe guard |
Harvia WL300 (stone-filled pipe guard) |
| Protective floor bedding |
Harvia WL100 (aluminium-zinc coated steel, black) |
| Pipe-mounted water heater |
WP250LD (chimney-mounted, with bench tap) |
| Chimney kit |
Harvia WHP1500M (black stainless steel) |
What's included
Harvia Legend 300DUO wood-burning sauna stove with exterior feed DUO fire chamber
Cast-iron framed glass door (reversible direction)
Grill
Ash box
Adjustable legs
Installation and operating instructions
2-year limited warranty (consumer use)
Required (not included): 573 lbs AC3020 stones - 13 boxes, 10-15 cm (additional box recommended); 6" North American flue adapter (Harvia WZ115155). Optional accessories (sold separately): WL200 protective sheath; WL300 smoke pipe guard; WL100 floor bedding; WP250LD pipe-mounted water heater; WHP1500M chimney kit. A licensed chimney professional is recommended for all flue installations. Wall penetration preparation required per installation manual.
Why the Harvia Legend 300DUO stands out
Sauna and fireplace - one fire, two rooms
The Legend 300DUO's through-wall fire chamber creates two completely different experiences from a single fire. Inside the sauna: 23.5kW of radiant wood heat, dense steam from 573 lbs of AC3020 stones, and the deep warmth of a traditional Finnish sauna session. In the adjacent room: the cast-iron glass door delivers a direct live view of the burning fire, with the warmth and atmosphere of an open fireplace. Both experiences are happening simultaneously from a single fire that only needs to be tended from one side - outside the sauna - without any interaction with the sauna interior. No other configuration achieves this dual-room dynamic without two separate fires.
Undisturbed sessions - wood loaded from outside
Loading wood from outside the sauna room means the fire can be tended, stoked, and managed without opening the sauna door, releasing heat, or interrupting the bathing session. In a cabin sauna with an adjoining relaxation room, one person can manage the fire from the lounge while bathers in the sauna remain completely undisturbed. The reversible door direction means the firebox opening can be set to face whichever direction the specific layout requires - left or right swing is decided at installation, not at purchase. Adjustable legs allow the stove body to be levelled precisely regardless of floor conditions.
573 lbs of stones - heat that outlasts the fire
The Legend platform is built around stone mass as the primary heat source. At 573 lbs, the stone bed accumulates thermal energy throughout the fire and releases it steadily after the fire dies down. The sauna session continues with full heat and steam quality long after wood loading has stopped - the stones are the heat reservoir, not the fire itself. For a long group session, a remote cabin sauna, or any installation where continuous fire tending is not practical, the Legend 300DUO's stone mass is the answer. Harvia describes it precisely: the large number of stones ensures good heat even if the fire dies down in between.
Split-air grate - cleaner burn, longer life
The Legend 300DUO fire chamber uses the same split-air combustion grate found across the full Legend lineup. A portion of the combustion air supply is routed to the upper section of the fire chamber above the primary burn zone, supporting more complete combustion of gases and reducing creosote buildup in the flue. The cleaner burn means less residue in the chimney, lower maintenance frequency, and better air quality from the flue. Harvia credits this grate design with extending the stove's operational lifespan - a meaningful benefit for a stove of this scale that is expected to serve for decades.
Compact safety clearances for a 23.5kW stove
Despite delivering 23.5kW with 573 lbs of stones, the Legend 300DUO's safety clearances to combustible materials are modest for its output class: 7.87" at both sides, 9.84" at the back. Bench placement within the sauna room retains meaningful flexibility. The optional WL200 protective sheath (sold separately, 1-3 panels as required) reduces side and back clearances to 3.94" when installed - providing further bench layout options in rooms where maximising usable area relative to the stove position is a priority.
Legend Series platform - DUO and standard configurations
The WKLE36DUOM is the exterior-feed DUO variant of Harvia's Legend 300 platform. The same 23.5kW platform is available as standard interior feed (Legend 300, WKLE36M) for installations where exterior wood loading is not required. The DUO-specific difference is the extended depth - 30.71" vs 25.98" for the standard Legend 300 - to accommodate the fire chamber wall extension. All Legend stoves are compatible with the WL200 protective sheath, WL300 smoke pipe guard, WL100 floor bedding, and WP250LD pipe-mounted water heater. Described by Harvia as handmade masterpieces by their master blacksmiths. Made in Finland. We are an authorized Harvia dealer.
About Harvia
Made in Finland - CE Certified - Legend Series DUO
Harvia Legend 300DUO. 23.5kW. 529-1,059 cu ft. DUO exterior feed. Fireplace view in adjacent room.
Harvia is a Finnish sauna and spa company established in 1950. The Legend 300DUO is the exterior-feed DUO variant of Harvia's 23.5kW Legend Series - a through-wall fire chamber that lets one person load wood and watch the fire from an adjacent room while another enjoys the sauna inside, with the cast-iron glass door providing a live fireplace view outside. 573 lbs of AC3020 stones (13 boxes) and a 6" North American flue adapter are required and sold separately. Pallet delivery. We are an authorized Harvia dealer.
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23.5kW wood-burning - 529-1,059 cu ft - no electricity required
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DUO exterior feed - wood from adjacent room - fireplace view outside sauna
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Cast-iron glass door - reversible direction - 573 lb stone mass
- Safety distances: front 27.56", sides 7.87", back 9.84"
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573 lbs AC3020 stones (13 boxes) required - 6" adapter required - both sold separately
Legend 300DUO vs Legend 300 vs PRO 20 SL - exterior feed stoves compared
Legend 300DUO vs Legend 300 vs PRO 20 SL - choosing the right exterior-feed or interior-feed stove
Three configurations are most relevant for buyers considering the Legend 300DUO. Legend 300 WKLE36M: same platform, interior feed - choose if loading from inside the sauna is acceptable and the fireplace view in an adjacent room is not a goal. Legend 300DUO WKLE36DUOM (this listing): 23.5kW, 529-1,059 cu ft, exterior feed, fireplace view in adjacent room, 573 lbs stones (13 boxes AC3020), 7.87" side clearances - the full Legend stone mass with DUO exterior-feed configuration. PRO 20 SL WKPR20SLM: 24.1kW, 283-706 cu ft, exterior feed, reversible cast-iron glass door, 88 lbs stones (2 boxes AC3020) - a smaller-room exterior-feed option with tighter safety clearances (4" sides) and a much lighter stone load. Choose the Legend 300DUO for the 529-1,059 cu ft large-room range where maximum stone mass (573 lbs) and long sustained heat after the fire dies down are the priority. Choose the PRO 20 SL for the 283-706 cu ft room range where a lighter stone load and tighter safety clearances are the right fit.
Manuals and Documents
Warranty
2-year limited warranty (consumer use)
The Harvia Legend 300DUO is covered by Harvia's 2-year limited warranty from the date of purchase for consumer use. The warranty covers defects in manufacturing and materials under normal use conditions. The warranty does not cover damage caused by improper installation, use of incorrect stone type or size (non-AC3020, or stones outside the 10-15 cm specified diameter range), operating without the required stone load, failure to follow the installation and operating guidelines in the manual, damage from inadequate chimney maintenance, soot fires, or improper wall penetration preparation for the DUO fire chamber extension. A licensed or certified chimney professional is recommended for all flue installation and regular chimney sweep maintenance. Proof of purchase from an authorized Harvia dealer is required for warranty claims. We are an authorized Harvia dealer.
