Cozy Heat SW Thru-Wall Sauna Stove
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The Cozy Heat SW TW Thru-Wall Wood-Burning Sauna Stove is a premium wood-fired heater designed for sauna lovers who want clean-burning performance and the convenience of through-the-wall loading. Hand-crafted in Estonia, where sauna bathing is a national tradition, the SW TW lets you feed the firebox from outside the sauna while delivering mild, long-lasting heat and rich steam over a large stone mass. Its efficient burn technology, German BIMSCH certification, and contemporary vertical design make this stove a powerful upgrade for traditional sauna rooms.
Key Features
- Thru-wall wood-burning sauna stove with firebox loading from outside the sauna
- Modern vertical body that saves floor space and enhances the look of custom sauna builds
- Clean-burning combustion with smoke gases up to six times cleaner than many traditional wood stoves
- High-efficiency design that uses approximately 25 to 40 percent less firewood than comparable sauna stoves
- Large stone capacity for deep heat storage and soft, long-lasting löyly
- Floor-mounted thru-wall installation ideal for new builds and serious sauna enthusiasts
- Designed and engineered in Estonia for performance, durability, and authentic sauna heat
Required Components
-
Sauna Stones:
- 12 kW: Minimum 265 lbs of sauna stones
- 18 kW: Minimum 353 lbs of sauna stones
- Chimney System: A compatible, code-compliant wood-burning sauna chimney and flue kit is required for safe installation.
What’s Included
- Cozy Heat SW TW thru-wall wood-burning sauna stove (12 kW or 18 kW model)
- Outer heater frame for thru-wall installation
- Heater body with stone basket
- Firebox and heater door with glass viewing window
- Cleaning hatch and ash box
- Connection components for chimney interface (per manufacturer kit)
- Installation and Operation Manual
- 2-year manufacturer warranty (residential use)
Specifications: Cozy SW TW 12 kW
| Model | Cozy SW-Thru-Wall 12 (SW TW 12 kW) |
| Heater Type | Wood-burning thru-wall sauna stove |
| Power Output | 12 kW |
| Sauna Room Size | 210 to 423 cu ft (approximately 6 to 12 m³) |
| Stone Requirement | Minimum 265 lbs of sauna stones |
| Maximum Firewood Length | 12.99 in (329 mm) |
| Firewood Diameter | 3.14 to 4.72 in (80 to 120 mm) |
| Minimum Room Height | 72 in (1828 mm) |
| Flue Connection Location | Top |
| Heater Weight | 161 lbs |
| Shipping Weight With Stones | 425 lbs |
| Safety Distance, Front to Back | 55.89 in (1420 mm) |
| Safety Distance, Left to Right | 33.85 in (860 mm) |
| Stove Depth | 27.16 in (690 mm) |
| Stove Width | 19.29 in (490 mm) |
| Stove Height | 32.12 in (816 mm) |
| Primary Fuel | Wood |
| Country of Origin | Estonia |
Specifications: Cozy SW TW 18 kW
| Model | Cozy SW-Thru-Wall 18 (SW TW 18 kW) |
| Heater Type | Wood-burning thru-wall sauna stove |
| Power Output | 18 kW |
| Sauna Room Size | 317 to 635 cu ft (approximately 9 to 18 m³) |
| Stone Requirement | Minimum 353 lbs of sauna stones |
| Maximum Firewood Length | 15.74 in (400 mm) |
| Firewood Diameter | 3.14 to 4.72 in (80 to 120 mm) |
| Minimum Room Height | 82 in (2096 mm) |
| Flue Connection Location | Top |
| Heater Weight | 236 lbs |
| Shipping Weight With Stones | 633 lbs |
| Safety Distance, Front to Back | 60.22 in (1530 mm) |
| Safety Distance, Left to Right | 40.54 in (1030 mm) |
| Stove Depth | 31.49 in (800 mm) |
| Stove Width | 21.65 in (550 mm) |
| Stove Height | 34.25 in (870 mm) |
| Primary Fuel | Wood |
| Country of Origin | Estonia |
Why Choose the Cozy Heat SW TW?
- Thru-wall loading keeps the sauna interior clean while you manage the fire from an adjacent room or exterior space
- Efficient, eco-conscious design that uses less fuel and produces cleaner exhaust compared to many traditional wood stoves
- Generous stone mass that stores heat and delivers smooth, long-lasting steam for authentic Finnish-style bathing
- European craftsmanship from a specialist sauna stove manufacturer in Estonia
Shipping and Returns
- Ships: Typically within 3 to 7 business days (freight appointment required)
- Delivery: Free standard U.S. shipping to most locations
- Returns: 14-day return policy on unused, uninstalled stoves in original packaging
Installation and Operation Manual
Frequently Asked Questions
What is the difference between the 12 kW and 18 kW Cozy SW TW models?
The 12 kW SW TW is designed for sauna rooms from 210 to 423 cubic feet. The 18 kW SW TW is built for larger rooms from 317 to 635 cubic feet. The 18 kW model supports more stones, accommodates longer firewood, and can heat larger rooms more quickly due to its higher output.
How does the thru-wall design work?
The firebox passes through the wall of the sauna so you load wood from an adjacent room or exterior space. This helps keep ash and debris out of the sauna interior and reduces heat loss since you do not need to open the sauna door each time you add wood.
How many stones do I need for each model?
The 12 kW SW TW requires at least 265 lbs of sauna stones. The 18 kW SW TW requires at least 353 lbs of stones. Many installers recommend buying an additional box of stones so you can choose shapes that fit well and allow for better airflow.
What type of stones should I use?
Use natural sauna stones such as olivine or peridotite in the 10 to 15 cm range. Do not use river rocks or decorative stones. Proper sauna stones are designed to withstand high temperatures and deliver better heat retention and steam quality.
Does the Cozy SW TW require a chimney?
Yes. A certified wood-burning chimney system is required for safe operation. Use a flue and chimney kit that meets local building and fire codes and is specifically rated for wood-burning sauna stoves. Professional installation is strongly recommended.
How long does it take to heat the sauna?
Typical heat-up time ranges from 45 to 75 minutes depending on room size, insulation, stone loading, and wood quality. The 18 kW model usually heats larger rooms more quickly because of its higher output and larger firebox.
Is the glass viewing window heat-resistant?
Yes. The stove uses heat-resistant, tempered glass so you can safely enjoy the view of the fire while maintaining a relaxing and comfortable sauna environment.
Do I need professional installation?
Professional installation is highly recommended. A qualified installer will configure the chimney, verify clearances to combustibles, and ensure the stove meets local building and fire safety requirements for wood-burning appliances.
Why Buy From Us
FAQs
Shipping & Delivery
Free curbside shipping on all orders. White-glove delivery/setup available at checkout in most areas. We’ll confirm your preferred date after purchase.
Warranty
Full manufacturer warranty, registered at purchase. Need help with a claim? Our U.S. support team handles it directly with the brand.
Returns
New, uninstalled items can be returned within the brand’s policy window. We’ll help coordinate pickup and any restocking requirements.
Installation & Power
Most saunas/hot tubs require dedicated circuits. We provide spec sheets and can recommend licensed installers in your area.
