The Cozy Heat SW Through-Wall Sauna Stove Package combines the dramatic sleek cylindrical design of the Cozy SW with through-wall installation - the smooth continuous column faces the sauna interior as its dominant visual feature, while the firebox passes through the sauna wall so that wood is loaded, fire is tended, and ash is removed entirely from outside the sauna room. The session stays undisturbed. The interior stays clean. Available in 12kW (210-423 cu ft) and 18kW (317-635 cu ft) with stone style selected at checkout, complete with stones included. The SW Through-Wall is the specific model for buyers who want the most visually dramatic form in the Cozy range - the cylindrical pillar - combined with the operational discipline of through-wall external firebox loading.
The SW cylindrical design with through-wall installation - drama inside, clean operation outside
The Cozy SW body is the most dramatic in the Cozy range: a sleek cylindrical column with smooth continuous curves and no angles or flat faces. In the SW Through-Wall, this cylindrical form stands inside the sauna room as a sculptural element - a pillar of radiant heat rising from the floor to the stone mass above, visible and commanding from every position in the room. The firebox that feeds it passes through the sauna wall; wood is loaded and the fire is managed from the adjacent exterior space without disturbing the bathers inside. This is a notable combination: a stove designed for visual impact inside the sauna, paired with an installation method that keeps all the operational work outside it. The cylindrical column commands the room; the fire behind the wall keeps it running. The sauna stays clean and the session stays uninterrupted.
Through-wall operation - what it changes
In the Cozy SW PKG (inside-loading version), wood is loaded through a firebox door that faces into the sauna room - the bather or attendant must enter the hot room to manage the fire. In the SW Through-Wall, the firebox opening is on the exterior side of the sauna wall, in the changing room, a utility corridor, or outdoors. Wood can be loaded while bathers are in session. Ash can be removed without entering the sauna. No wood chips, bark, or ash on the sauna floor around the base of the cylinder. No smoke entering the room when the firebox door opens. The traditional Nordic and Baltic sauna design principle - bathing chamber clean and separate from the stoke-hole - applied to the most contemporary stove form in the Cozy range. The exterior of the sauna building must have an accessible adjacent space on the firebox side of the wall, and the wall penetration must be installed by a qualified professional before the stove can be used.
Same Cozy Heat engineering - 5mm stainless flame cutter throughout
Every technical specification of the Cozy Heat range applies to the SW Through-Wall without modification: 5mm stainless steel flame cutter, three-stage combustion with primary, secondary, and tertiary air injection burning the flue gases as a third combustion stage, 25-40% firewood reduction compared to comparable stoves, 73.9% efficiency at 12kW and 81.3% at 18kW, and German BlmSchV DIN EN 13240 Level 2 and EN 15821:2010 certification. A chimney installation is required and sold separately. The installation is more involved than any conventional floor-standing Cozy model - both the wall penetration and the chimney must be planned and installed before the stove arrives.
Wood-burning sauna stove package combining sleek cylindrical design with through-wall installation - available in 12kW (210-423 cu ft) and 18kW (317-635 cu ft), select at checkout. Includes Cozy SW Through-Wall stove and sauna stones (stone style selected at checkout). Dramatic cylindrical column - smooth continuous curves - faces sauna interior. Firebox passes through sauna wall - wood loaded, fire tended, ash removed from outside. Clean interior, bathers undisturbed during session. 5mm stainless steel flame cutter. Three-stage combustion - 25-40% less firewood. EN 15821:2010 and German BlmSchV DIN EN 13240 Level 2 certified. 12kW: 73.9% efficiency. 18kW: 81.3% efficiency. No electrical required. Chimney required - sold separately. Wall penetration installation required - by qualified professional. Handmade in Estonia. 2-year warranty.
Package - stove + stones included Sleek cylindrical design + through-wall 12kW (210-423 cu ft) or 18kW (317-635 cu ft) Dramatic cylindrical column inside sauna Firebox from outside - clean interior Bathers undisturbed during session Three-stage combustion 25-40% less firewood than comparable stoves 5mm stainless steel flame cutter EN 15821:2010 certified German BlmSchV DIN EN 13240 Level 2 Chimney required - sold separately Handmade in Estonia 2-year warranty
Specifications
Output selection - choose at checkout
| 12kW |
210 to 423 cu ft | Min 265 lbs stones | 73.9% efficiency |
| 18kW |
317 to 635 cu ft | Min 353 lbs stones | 81.3% efficiency |
| Electrical required |
None |
| Chimney required |
Yes - sold separately |
| Stone style |
Selected at checkout |
Design, installation and combustion
| Design feature |
Sleek cylindrical column - smooth continuous curves |
| Installation type |
Through-wall - firebox on exterior side of sauna wall |
| Stone mass location |
Inside sauna room |
| Firebox door location |
Outside sauna room |
| Combustion stages |
Three-stage: primary, secondary, tertiary |
| Firewood reduction |
25-40% less than comparable stoves |
| Certification |
EN 15821:2010 | BlmSchV DIN EN 13240 Level 2 |
Firebox opening dimensions
| 12kW minimum opening width |
10.0" (255 mm) |
| 12kW minimum floor height |
17.3" (440 mm) |
| 18kW minimum opening width |
12.4" (315 mm) |
| 18kW minimum floor height |
18.5" (470 mm) |
Construction
| Design |
Sleek cylindrical column - smooth continuous curved surface |
| Flame cutter material |
5mm stainless steel |
| Body construction |
Steel |
| Flue outlet position |
Top of stove |
| Origin |
Handmade in Estonia |
Installation requirements
| Wall penetration |
Required - correctly sized and fire-protected |
| Adjacent space required |
Yes - on exterior firebox side of sauna wall |
| Chimney |
Required - sold separately |
| Professional installation |
Required |
| Shared flue system |
Not suitable |
| Firewood |
Dry seasoned hardwood required |
Warranty
| Warranty period |
2 years |
| Overfiring |
Not covered |
| Chimney sweeping |
Required regularly |
What's included
Cozy Heat SW Through-Wall wood-burning sauna stove (12kW or 18kW - selected at checkout)
Sauna stones - style selected at checkout (min 265 lbs / 12kW, min 353 lbs / 18kW)
Installation and operation manual
Not included (required for operation): Chimney and flue pipe installation (sold separately); wall penetration installation materials and labour (by qualified professional). Optional: Additional sauna stones.
Why the Cozy Heat SW Through-Wall Package stands out
Cylindrical drama inside, clean operation outside
The SW's sleek cylindrical column stands inside the sauna room as its dominant visual element - a pillar of smooth curves and radiant heat that commands attention from every position in the room. The firebox feeds it from through the wall. The two qualities rarely combined: the most visually dramatic Cozy form, paired with the most operationally clean installation method.
Clean sauna interior, undisturbed session
Wood loaded, fire tended, and ash removed from outside without entering the sauna. No wood, bark, ash, or smoke inside the room. No interruption to the session. For sauna rooms where the cylindrical stove is the centrepiece and the interior should stay immaculate throughout the session, the SW Through-Wall is the correct choice.
Traditional Nordic installation, contemporary form
Through-wall firebox loading is the oldest installation principle in Nordic and Baltic sauna culture - the design that kept the bathing space separate from fire management. The SW Through-Wall pairs this traditional functional arrangement with the most contemporary and dramatic stove form in the Cozy range: a cylindrical column, smooth and modern in every line.
Three-stage combustion - 25-40% less firewood
Primary, secondary, and tertiary air injection burns flue gases as a third combustion stage - 73.9% efficiency at 12kW, 81.3% at 18kW, up to 6x cleaner smoke gases. Certified to Germany's BlmSchV DIN EN 13240 Level 2 and EN 15821:2010. Identical combustion performance to every other Cozy Heat model.
5mm stainless flame cutter
The most thermally stressed component is fabricated from 5mm stainless steel across every Cozy Heat model - substantially heavier than industry standard. Resists warping and corrosion through years of sustained firing cycles, extending stove service life well beyond lower-specification alternatives.
Professional installation required - plan first
The wall penetration must be correctly sized and fire-protected by a qualified professional. A chimney must be installed separately. An accessible adjacent space on the exterior firebox side is required. Confirm the building layout and engage a qualified installer before ordering the SW Through-Wall.
About Cozy Heat
Handmade in Estonia - cylindrical drama, external loading
Cozy Heat SW Through-Wall. The dramatic cylindrical Cozy with the traditional external firebox installation.
Cozy Heat is an Estonian sauna stove manufacturer. The SW Through-Wall is the model for buyers who want the striking visual presence of the cylindrical SW column inside the sauna room and the operational cleanliness of through-wall external firebox loading outside it. The same 5mm stainless flame cutter, three-stage combustion, and German EN 15821:2010 certification as every Cozy model. When both the SW's dramatic form and the Through-Wall's clean operation matter, and the building layout supports it, the SW Through-Wall is the specific model that delivers both.
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Complete package - Cozy SW Through-Wall stove and stones (style at checkout)
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Cylindrical column inside sauna, firebox outside - drama inside, clean operation outside
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12kW (210-423 cu ft) or 18kW (317-635 cu ft) - select at checkout
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Three-stage combustion - 25-40% less firewood, EN 15821:2010 certified
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Professional wall installation required - plan before purchasing
SW Through-Wall vs its alternatives
Choosing between the SW Through-Wall and its nearest alternatives
Cozy SW PKG (SKU 129784): sleek cylindrical design, inside-loading firebox - for buyers who want the SW's dramatic column but load from inside the sauna. Cozy Through-Wall PKG (SKU 129792): through-wall external loading, conventional stove body - for buyers who want external loading without the cylindrical form. Cozy SW Through-Wall (this listing): cylindrical column inside the sauna, firebox through the wall - the specific choice when both the SW's visual drama and the Through-Wall's clean operation are wanted together and the building layout supports it. All three share identical technical performance, output levels, stone requirements, certifications, and warranty.
A chimney and correctly installed wall penetration are required. Use only dry, seasoned hardwood. Do not overfire. Sweep the chimney regularly. A qualified professional must carry out the wall and chimney installation.
Manuals and Documents
Warranty
2-year warranty
The Cozy Heat SW Through-Wall Sauna Stove is covered by a 2-year limited warranty from the date of purchase. The warranty covers defects in manufacturing and materials under normal use conditions. The warranty does not cover: damage caused by overfiring; failure to use dry, seasoned firewood; failure to regularly sweep the chimney; failure to follow installation requirements including proper wall penetration and chimney installation by a qualified professional; or improper modification of the stove. Proof of purchase from an authorized Cozy Heat dealer is required. We are an authorized Cozy Heat dealer.
