Description
PRODUCT DESCRIPTION

The CozyHeat Cozy12 SW is a sleek, curved wood-burning sauna heater crafted for soft, long-lasting heat and rich steam. With a tested output of 11.5 kW, it’s ideal for sauna rooms of 6–13 m³. Built in Estonia and TÜV tested to meet German BImSchV clean-burn requirements, it produces up to 6× cleaner flue gases while using 25–40% less wood fuel than similar stoves.
Available in INTERNAL and EXTERNAL (through-wall) versions, the Cozy12 SW uses a three-stage combustion air system for efficient, even heating. It accepts up to 120 kg of sauna stones (stones sold separately), burns dry wood logs up to 30–33 cm with a typical max load of 8 kg, and offers compact clearances—only 17 cm to flammable materials at the sides without additional protection screens.
Shaped with a modern curved body and backed by generations of sauna expertise, the Cozy12 SW delivers balanced heat distribution, smooth steam generation, and energy-smart performance—bringing authentic löyly to your sauna with contemporary CozyHeat engineering.
FEATURES

High Heat Output – 11.5 kW
With a powerful 11.5 kW output, the CozyHeat Cozy12 SW is designed for sauna rooms sized between 6 to 13 m³. Its three-stage combustion system delivers steady, comfortable heat with excellent fuel efficiency.
Generous Stone Capacity – up to 120 kg
The SW accommodates up to 120 kilograms of sauna stones (stones sold separately), providing superb heat storage and smooth steam generation for mild, long-lasting löyly.
Advanced Three-Stage Combustion
Combustion air is routed through the grate, mid-chamber channels, and ceiling tubes to reburn gases—resulting in up to 6× cleaner flue gases and 25–40% less wood use compared to similar heaters.
Sleek Curved Design
The SW’s modern curved body holds a large stone mass for stable temperatures and gentle steam, blending contemporary style with authentic wood-fired performance.
Compact Safety Clearances
Practical for tight layouts: only 17 cm to flammable materials at the sides without extra protection screens. Standard clearances: Sides 170 mm, Back 230 mm, Front 500 mm, Ceiling 1130 mm.
Flexible Installation
Available in INTERNAL and EXTERNAL (through-wall) versions. Burns dry wood logs up to 30–33 cm with a typical max fuel load of 8 kg. Top flue outlet Ø114 mm for a clean chimney connection.


Instructions for Using Your Cozy Sauna Heater

Piling of the Sauna Stones
Properly arranging sauna stones in your wood-burning heater is essential for both safety and performance. Follow these guidelines:
Use only suitable sauna stone materials such as peridotite, olivine diabase, olivine, or vulcanite.
Stones should be 5–15 cm in diameter. Select medium-sized, dense stones for optimal heat retention.
Wash the stones thoroughly to remove any dust or loose particles before placing them in the heater.
Place stones gently and evenly into the heater’s stone compartment — never drop them, as this can damage the heater or the stones.
Stack stones loosely to allow proper airflow between them. Good circulation ensures efficient burning and even heating.
Position stones so they support each other without blocking airflow through the heater.
Do not pile stones too high above the stone compartment — this can restrict ventilation and reduce efficiency.
Never place foreign objects (such as decorative stones or metal items) in the heater, as they may alter airflow or create safety hazards.
Correct stone placement helps your firewood heater burn more efficiently, extend its lifespan, and deliver the authentic, gentle heat that a traditional sauna is known for.
Heater Maintenance
Sauna stones can disintegrate due to temperature fluctuations. Rearrange stones at least annually, or more often with frequent sauna use.
Remove any disintegrated stones from the heater’s bottom and replace them with new ones to maintain optimal heating and prevent overheating.
Heating Your Sauna with Cozy Sauna Heater
When using the heater for the first time, both the heater and stones may emit odors. Efficiently ventilate the sauna room to remove these odors. If the heater’s output matches the sauna room’s size, it will take about an hour for a properly insulated sauna to reach the desired bathing temperature. The sauna stones typically reach this temperature simultaneously with the sauna room.
SPECIFICATIONS
Specification | COZY 12 SW (Internal) | COZY 12 SW-TW (External / Through-Wall) |
---|---|---|
Power Output | 11.5 kW | |
Recommended Room Volume | 6–13 m³ | |
Stone Capacity | Up to 120 kg (stones not included) | |
Fuel Type | Dry wood logs up to 30–33 cm | |
Max Fuel Load | 8 kg | |
Efficiency | 73.9% (EN 15821 tested) | |
Heater Dimensions (L × W × H) | 541 × 490 × 816 mm | 691 × 490 × 816 mm |
Weight of sauna stove | 68 kg | 79 kg |
Safety Distances | Ceiling: 1130 mm / Sides: 170 mm / Back: 230 mm / Front: 500 mm | |
Compliance | EN 15821:2010, BImSchV Level 2, TÜV SÜD tested |
WHAT’S INCLUDED
CozyHeat Cozy12 SW 11.5 kW Wood-Burning Sauna Heater (choose INTERNAL or EXTERNAL/through-wall variant)
Glass door with durable steel frame
Removable ash pan
Operating tool (stove iron) & safety glove/cloth
User manual & installation instructions
EXPERIENCE TRADITIONAL SAUNA COMFORT WITH COZYHEAT
The CozyHeat Cozy12 SW brings authentic wood-fired löyly to saunas of 6–13 m³. Its sleek curved body and 11.5 kW output provide balanced, long-lasting heat, while TÜV-tested, BImSchV clean-burn performance delivers up to 6× cleaner flue gases using 25–40% less wood. With capacity for up to 120 kg of stones (sold separately) and compact clearances, the SW blends modern design with traditional sauna feel.
Choose INTERNAL or EXTERNAL (through-wall) installation and complete your setup with a Cozy Chimney Kit, protective base, panels, and sauna stones. Elevate your ritual and enjoy smooth, gentle steam—crafted by CozyHeat, available at Shym Saunas.

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