Cozy Heat OG Thru-Wall Sauna Stove
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The Cozy Heat OG TW Thru-Wall Wood-Burning Sauna Stove is a premium, hand-crafted heater designed for traditional sauna lovers who want clean-burning performance and through-the-wall convenience. Built in Estonia, where sauna bathing is a national tradition, this wood-fired sauna stove delivers mild, long-lasting heat and rich steam while allowing you to load firewood from outside the sauna. The OG TW’s distinctive trilateral body, efficient burn technology, and large stone capacity create a powerful, authentic wood-burning sauna experience.
Key Features
- Thru-wall wood-burning sauna stove with firebox loading from outside the sauna
- Artistically designed trilateral body that elevates the look of any custom sauna room
- Clean-burning construction with smoke gases up to six times cleaner than typical wood stoves and reduced fuel consumption
- High stone capacity for deep heat storage and soft, long-lasting löyly
- Floor-mounted steel frame built for durability and heavy daily use
- Designed and engineered in Estonia with a focus on efficiency, safety, and traditional sauna comfort
Required Components
-
Sauna Stones:
- 12 kW: Minimum 265 lbs of sauna stones
- 18 kW: Minimum 353 lbs of sauna stones
- Chimney System: A compatible wood-burning sauna chimney and flue kit that meets local building and fire codes.
What’s Included
- Cozy Heat OG TW wood-burning sauna stove (12 kW or 18 kW model)
- Outer heater frame and thru-wall firebox assembly
- Heater door with glass viewing window
- Heater body, cleaning hatch, and ash drawer
- Connection components for chimney interface (per manufacturer kit)
- Installation and Operation Manual
- Manufacturer 2-year warranty (residential use)
Specifications: Cozy OG TW 12 kW
| Model | Cozy OG TW 12 kW (Thru-Wall) |
| 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 | 12.95 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 | 139 lbs |
| Shipping Weight With Stones | 404 lbs |
| Safety Distance, Front to Back | 56.09 in (1425 mm) |
| Safety Distance, Left to Right | 34.05 in (865 mm) |
| Dimensions (W x D x H) | 16.92 in x 27.36 in x 27.55 in (430 mm x 695 mm x 700 mm) |
| Primary Fuel | Wood |
| Country of Origin | Estonia |
Specifications: Cozy OG TW 18 kW
| Model | Cozy OG TW 18 kW (Thru-Wall) |
| 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 | 199 lbs |
| Shipping Weight With Stones | 551 lbs |
| Safety Distance, Front to Back | 60.42 in (1535 mm) |
| Safety Distance, Left to Right | 40.74 in (1035 mm) |
| Dimensions (W x D x H) | 19.68 in x 31.69 in x 29.76 in (500 mm x 805 mm x 756 mm) |
| Primary Fuel | Wood |
| Country of Origin | Estonia |
Why Choose the Cozy Heat OG TW?
- Thru-wall loading keeps your sauna interior clean while wood is loaded from an adjacent room or exterior area
- High-efficiency wood-burning design that uses less fuel and produces cleaner exhaust compared to many traditional stoves
- Large stone mass for deep thermal storage and smooth, long-lasting steam
- Hand-crafted European construction from a specialist sauna heater manufacturer in Estonia
Shipping and Returns
- Ships: Typically within 3 to 7 business days (appointment required for freight delivery)
- Delivery: Free standard U.S. shipping to most locations
- Returns: 14-day return policy on unused, uninstalled items in original packaging
Installation and Operation Manual
Frequently Asked Questions
What is the difference between the 12 kW and 18 kW Cozy OG TW models?
The 12 kW OG TW is ideal for sauna rooms from 210 to 423 cubic feet, while the 18 kW OG TW is designed for larger saunas from 317 to 635 cubic feet. The 18 kW model supports a larger room volume, uses more stones, and accepts longer firewood, which can shorten heat-up time in big sauna rooms.
Does the Cozy OG TW require a chimney?
Yes. A certified wood-burning chimney system is required for safe installation. Use a flue and chimney kit that meets local codes and is rated for wood-burning sauna stoves. Professional installation is strongly recommended.
How does the thru-wall design work?
The firebox extends through the wall, so you load wood from an adjacent room or exterior area. This design keeps ashes and wood debris out of the sauna interior and allows you to manage the fire without opening the sauna door and losing heat.
How many stones do I need for each model?
The 12 kW OG TW requires a minimum of 265 pounds of sauna stones. The 18 kW OG TW requires a minimum of 353 pounds of stones. Many installers recommend purchasing an extra box of stones to hand-select the best pieces for fit and airflow.
What type of stones should I use?
Use natural, high-heat sauna stones such as olivine or peridotite in the 10 to 15 cm range. Do not use river rocks or decorative stones, since they can crack or explode under high heat. Proper sauna stones improve heat retention and steam quality.
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 type. The 18 kW model generally heats larger rooms more quickly due to its higher output and larger firebox.
Is the glass viewing window heat-resistant?
Yes. The door uses heat-resistant, tempered glass that allows you to monitor the fire while maintaining safe operation and a relaxing visual ambiance inside the sauna.
Do I need professional installation?
Professional installation is highly recommended. A qualified installer can ensure proper chimney configuration, safe clearances to combustibles, and full compliance with local building and fire codes 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.
