Cozy Heat SW Thru-Wall – Wood-Burning Sauna Stove | 12 kW & 18 kW

Cozy Heat SW Thru-Wall – Wood-Burning Sauna Stove | 12 kW & 18 kW

Made in Estonia | External Firebox Access | Traditional Wood-Fired Heat | Efficient Combustion | 12 kW & 18 kW Options | Free U.S. Shipping

Experience authentic wood-fired sauna bathing with the Cozy Heat SW Thru-Wall Wood-Burning Sauna Stove, a premium Estonian-crafted heater that combines traditional sauna warmth with innovative, efficient design.

Featuring a through-wall firebox, cylindrical steel construction, and advanced combustion technology, the Cozy Heat SW Thru-Wall allows you to maintain the fire from outside the sauna room while enjoying consistent, enveloping warmth inside.

Available in 12 kW and 18 kW models, this thoughtfully engineered stove offers the flexibility to heat intimate personal saunas or larger shared wellness spaces.

Whether you're building a backyard sauna retreat or upgrading an existing wood-fired installation, Cozy Heat brings traditional European craftsmanship and modern heating efficiency together.

Why Choose the Cozy Heat SW Thru-Wall?

Convenient External Firebox Access

The defining feature of the Cozy Heat SW Thru-Wall is its extended firebox, designed to pass through an appropriately constructed wall.

This configuration allows you to add firewood and manage the fire from an adjacent room or designated exterior access area.

Keep firewood storage and routine fire tending separate from the sauna interior for a cleaner, more comfortable bathing environment.

Authentic Wood-Fired Sauna Warmth

Enjoy the natural warmth and atmosphere of a traditional wood-burning sauna.

Unlike electric or infrared systems, the Cozy Heat SW uses real firewood to generate heat, creating a classic sauna experience with the gentle sounds and character of a wood fire.

Its generous sauna stone capacity helps retain heat and supports a comfortable, consistent sauna environment.

Traditional Steam Sauna Experience

The Cozy Heat SW is designed for use with appropriate sauna stones.

As the stones heat, they provide the thermal mass needed for traditional sauna bathing.

Carefully adding water to the heated stones creates bursts of steam, allowing you to adjust the humidity and sensation of your sauna session.

Enjoy anything from dry sauna warmth to a more humid, steam-filled experience according to your preferences.

Advanced, Fuel-Efficient Combustion

Cozy Heat incorporates an engineered combustion system designed to improve burning efficiency while reducing smoke emissions.

According to manufacturer-reported comparisons, Cozy Heat stoves can use approximately 25–40% less firewood than selected conventional sauna heaters.

The manufacturer also describes substantially cleaner smoke emissions and compliance with applicable German BImSchV requirements.

Actual fuel consumption and emissions depend on installation, fuel quality, chimney draft, and operating conditions.

Premium Estonian Craftsmanship

Designed, engineered, and manufactured in Estonia, the Cozy Heat SW reflects generations of traditional sauna expertise.

Its heavy-duty steel construction incorporates a 5 mm stainless steel flame cutter, designed to withstand repeated exposure to intense heat.

The result is a robust sauna heater designed for long-term performance and frequent use.

Elegant Cylindrical Design

The Cozy Heat SW features a contemporary cylindrical profile that combines attractive styling with practical sauna heating.

The open stone-surround design provides generous space for sauna stones while creating a distinctive architectural feature inside the sauna.

Its clean lines complement both traditional wood-paneled interiors and modern custom sauna designs.

Available in Two Heating Capacities

Choose the model best suited to your sauna room.

Cozy Heat SW Thru-Wall 12 kW

Designed for sauna rooms approximately 210–423 cubic feet (6–12 m³).

Ideal for smaller to medium-sized traditional sauna installations.

Cozy Heat SW Thru-Wall 18 kW

Designed for sauna rooms approximately 317–635 cubic feet (9–18 m³).

Well suited to larger residential sauna rooms and spacious shared sauna environments.

Correct heater sizing depends on room volume, insulation, ceiling height, glass surfaces, and other construction characteristics.

Designed for Flexible Sauna Installations

The through-wall design is particularly appealing for custom sauna projects where convenient external fire tending is a priority.

It can be integrated into appropriately designed sauna buildings with a compatible wall opening, noncombustible protection, proper chimney system, and required safety clearances.

Ideal for Your Sauna & Wellness Space

Backyard Wood-Fired Saunas

Create an authentic traditional sauna with the convenience of external firebox access.

Custom Sauna Construction

Incorporate an efficient, premium wood-burning stove into a purpose-built sauna room.

Post-Adventure Relaxation

Enjoy traditional sauna warmth after skiing, hiking, cycling, and other outdoor activities.

Shared Wellness Experiences

Create an inviting sauna environment for relaxing with family and friends.

Traditional Sauna Enthusiasts

Enjoy the atmosphere of wood-fired heat and the ability to create steam using heated sauna stones.

Key Features

• Through-Wall Firebox: Add firewood from outside the sauna room.

• Traditional Wood-Burning Operation: Authentic sauna warmth without an electric heating element.

• 12 kW & 18 kW Models: Two heating capacities for different sauna sizes.

• Made in Estonia: Premium European sauna craftsmanship.

• High-Efficiency Combustion: Designed to reduce unnecessary wood consumption.

• Reduced Smoke Emissions: Manufacturer-reported cleaner combustion performance.

• 5 mm Stainless Steel Flame Cutter: Heavy-duty heat-resistant component.

• Cylindrical Steel Construction: Distinctive and durable design.

• Generous Stone Capacity: Supports consistent heat and traditional steam.

• Top Flue Connection: Designed for appropriate chimney installations.

• External Fire Management: Keeps routine fire tending separate from the sauna interior.

• 2-Year Limited Manufacturer Warranty: Subject to applicable coverage terms.

• Free U.S. Shipping: Available to eligible destinations.

Technical Specifications

Specification	SW Thru-Wall 12	SW Thru-Wall 18
Brand	Cozy Heat	Cozy Heat
Model	SW-TW 12	SW-TW 18
Heating Type	Wood-Burning	Wood-Burning
Nominal Heating Capacity	12 kW	18 kW
Recommended Sauna Volume	210–423 cu. ft.	317–635 cu. ft.
Sauna Volume (Metric)	6–12 m³	9–18 m³
Minimum Sauna Room Height	72"	82"
Fuel Type	Seasoned Firewood	Seasoned Firewood
Maximum Firewood Length	Approx. 13"	Approx. 15.7"
Stove Width	19.29"	21.65"
Stove Depth	27.16"	31.49"
Stove Height	32.12"	34.25"
Heater Weight Without Stones	Approx. 161 lb	Approx. 236 lb
Flue Connection	Top	Top
Combustion Chamber Extension	Through-Wall	Through-Wall
Construction	Steel with Stainless Steel Flame Cutter	Steel with Stainless Steel Flame Cutter
Required Chimney Draft	12 Pa	12 Pa
Installation	Floor-Mounted, Through-Wall	Floor-Mounted, Through-Wall
Warranty	2-Year Limited	2-Year Limited

What's Included

The Cozy Heat SW Thru-Wall stove assembly includes:

• Cozy Heat SW Thru-Wall Sauna Stove in Selected Size

• Cylindrical Outer Heater Frame

• Wood-Burning Heater Body

• Extended Through-Wall Firebox

• Firebox Door with Glass

• Ash Collection Box

• Cleaning Access Components

• Manufacturer-Supplied Flue Connection Component

• Installation & Operating Manual

A complete chimney system, sauna stones, fire-protection components, and installation materials may be purchased separately depending on your selected package and installation requirements.

Installation & Setup

The Cozy Heat SW Thru-Wall is a wood-burning appliance requiring careful planning and professional installation.

1. Choose Your Model: Select the 12 kW or 18 kW version based on sauna volume, insulation, and construction.

2. Plan the Through-Wall Opening: Incorporate a manufacturer-approved wall penetration with appropriate noncombustible materials and clearances.

3. Prepare the Foundation: Position the stove on a stable, heat-resistant surface meeting applicable installation requirements.

4. Install the Chimney System: Use a compatible, properly sized flue and chimney designed for wood-burning sauna appliances.

5. Ensure Proper Ventilation: Provide adequate combustion air and sauna ventilation.

6. Complete Initial Firing: Follow the manufacturer's instructions for the first heating and protective coating curing.

7. Load the Sauna Stones: Arrange approved sauna stones in accordance with manufacturer requirements.

8. Operate Safely: Use properly seasoned firewood and follow the recommended firing procedures.

Professional installation is strongly recommended. Through-wall wood-burning installations require appropriate fire-rated construction, chimney design, ventilation, and compliance with local building and fire codes.

Shipping & Delivery

FREE U.S. SHIPPING

Enjoy complimentary U.S. shipping on your Cozy Heat SW Thru-Wall Sauna Stove to eligible destinations.

• Order Processing: Typically packed and shipped within 1–3 business days.

• Estimated Delivery: Approximately 5–10 business days.

• Available Models: 12 kW and 18 kW.

• Delivery Method: Large-item freight or other suitable carrier arrangements.

Shipping timelines are supplier-provided estimates and may vary by location, carrier scheduling, and product availability.

Frequently Asked Questions

What makes the Cozy Heat SW Thru-Wall different from the standard SW stove?

The Thru-Wall model features an extended firebox that allows wood to be added from an adjacent area outside the sauna room. The standard SW is designed for tending the fire from inside the sauna.

Does the Cozy Heat SW Thru-Wall require electricity?

No electrical heating connection is required. The stove generates heat by burning firewood.

What is the difference between the 12 kW and 18 kW models?

The 12 kW model is designed for sauna rooms of approximately 210–423 cubic feet. The 18 kW model serves approximately 317–635 cubic feet.

The correct choice depends on sauna construction and heating requirements.

Can I pour water over the sauna stones?

Yes. When properly equipped with approved sauna stones, the Cozy Heat SW supports traditional steam-producing sauna bathing. Follow the manufacturer's instructions for water application.

Does the stove need a chimney?

Yes. A properly designed and installed chimney and flue system are required to safely vent combustion gases.

Can the firebox be accessed from outside the sauna building?

The extended firebox is designed for access from the opposite side of an appropriately constructed wall. Exterior access may be possible as part of a manufacturer-approved installation with suitable weather protection and fire-safety measures.

What kind of wood should I use?

Use dry, seasoned firewood that meets the manufacturer's fuel recommendations. Never burn treated, painted, or contaminated wood.

Is the Cozy Heat SW Thru-Wall suitable for an existing sauna?

Potentially. An existing sauna must have sufficient space, structural support, ventilation, chimney access, and a suitable wall for the through-wall configuration.

What warranty does Cozy Heat offer?

Cozy Heat SW Thru-Wall stoves are advertised with a two-year limited manufacturer warranty, subject to the applicable terms.

Authentic Sauna Warmth. Designed Around Convenience.

The Cozy Heat SW Thru-Wall Wood-Burning Sauna Stove combines traditional wood-fired heating with thoughtful design that keeps fire tending outside the sauna room.

With its elegant cylindrical construction, efficient combustion system, generous sauna stone capacity, and premium Estonian craftsmanship, it creates an authentic sauna experience with added everyday convenience.

Whether you're planning a private backyard sauna or upgrading a custom wellness retreat, the Cozy Heat SW Thru-Wall offers a sophisticated approach to traditional sauna heating.

Real fire. Timeless warmth. A cleaner, more peaceful sauna experience.

Important Safety Information

This is a wood-burning sauna stove. Installation must comply with all manufacturer instructions, local building codes, and applicable fire-safety requirements.

A suitable chimney system, proper ventilation, noncombustible wall penetration, and required clearances are essential.

Never operate the stove without proper venting. Install appropriate smoke and carbon monoxide alarms where required.

Only use approved sauna stones and properly seasoned firewood. Follow the manufacturer's recommendations for firing, cleaning, maintenance, and adding water to the stones.

Never leave an operating wood-burning stove unattended.

Sauna bathing involves elevated temperatures and may not be appropriate for everyone. Individuals with cardiovascular conditions, uncontrolled blood pressure, impaired heat sensitivity, or other relevant medical concerns should consult a qualified healthcare professional before use.