The Carbon Smart™ Indoor Sauna Kit gives you everything you need to build a professionally finished, full-size sauna room in your home—without the guesswork. Precision-cut Thermo Poplar components, a full-glass door, benches, lighting, and accessories arrive ready to install. You supply the framing, insulation, electrical, and exterior wall covering; we handle the rest.
Why Customers Choose This Kit
- Complete interior package—no sourcing individual components
- Thermo Poplar wood is thermally modified without chemicals for lasting stability
- Configurable bench layouts to fit your space and preference
- Optional 9KW heater bundles from Harvia and EOS—add at checkout
- Optional accessory upgrades: bench skirting, LED under-bench lighting, or both
- Detailed installation instructions included for DIY or contractor builds
- Suitable for residential and light commercial installations
Product Highlights
Thermo Poplar Interior Wood
Sustainably sourced and thermally modified at approximately 374°F, Thermo Poplar delivers enhanced dimensional stability and improved resistance to humidity—achieved through a chemical-free process. The result is a warm, rich tone that holds up beautifully in high-heat sauna environments.
Full-Glass Sauna Door
The included all-glass door with wood handles and trim fits a 28″ × 80″ rough opening (frame: 27.2″ × 78.7″; glass: 24.4″ × 77.3″). It provides a clean, modern look while maintaining proper heat retention.
Configurable Bench Layouts
Choose from multiple bench configurations shown in the product images. Each layout uses 20″-deep clear Thermo Poplar bench boards with supports, custom-built to your selected configuration.
Proper Ventilation & Moisture Control
Upper and lower vent grills promote healthy air circulation, while the included foil vapor barrier protects your wall assembly from moisture damage over time.
Marine-Grade Vapor-Proof Lighting
A wall-mount, marine-grade vapor-proof sauna light is included—rated for the high-humidity sauna environment and ready to wire into your electrical plan.
Optional Heater Bundles
Select a 9KW heater at checkout—choose from Harvia Cilindro, Harvia Virta, EOS Cubo Avantgarde, or EOS Mythos S35. All heater options include heater stones. See the comparison chart below for details.
What's Included
- Foil vapor barrier
- Ergonomic backrests (shipped flat; on-site spacers can create an angled pitch)
- 1×4 tongue & groove wall and ceiling boards – Thermo Poplar
- Clear 1×4 bench boards with supports (20″ deep) – Thermo Poplar, custom to your configuration
- Corner moldings for walls, ceiling, and baseboards – Thermo Poplar
- All-glass sauna door with wood handles and trim (rough opening: 28″ × 80″)
- Duckboard flooring for walk area – Thermo Poplar
- Upper and lower vent grills
- Traditional sauna bucket with liner and ladle
- Sauna thermometer
- Headrest
- Marine-grade wall-mount vapor-proof sauna light
- Detailed installation instructions
Specifications
| Room Dimensions | 6′ × 9′ × 8′ (interior) |
| Recommended Ceiling Height | 8 feet (per manufacturer safety guidelines) |
| Wood Species | Thermo Poplar (thermally modified, chemical-free) |
| Wall & Ceiling Boards | 1×4 tongue & groove, horizontal run (seam added if width exceeds 8 ft) |
| Bench Depth | 20 inches |
| Door Frame Size | 27.2″ × 78.7″ (690 × 2000 mm) |
| Door Glass Size | 24.4″ × 77.3″ (620 × 1963 mm) |
| Door Frame Thickness | 1.65″ × 3.6″ (42 × 92 mm) |
| Rough Opening Required | 28″ × 80″ |
| Heater Options (optional) | 9KW – Harvia Cilindro PC90, PC90E, Virta; EOS Cubo Avantgarde, Mythos S35 |
| Accessory Options | No Accessories / Bench Skirting / LED Under-Bench Lighting / Luxury Package (both) |
| Shipping Weight (approx.) | 800 lbs |
| Brand | Finnish Sauna Builders – Carbon Smart™ Line |
Ideal For
- Homeowners converting a basement, garage, or spare room into a dedicated sauna space
- DIY builders and contractors looking for precision-cut, ready-to-install components
- Residential wellness rooms, home gyms, and spa additions
- Light commercial installations such as boutique fitness studios or wellness centers
- Buyers who want a complete kit with optional heater and accessory bundles in one order
Important Information
- This kit supplies all interior sauna components. Framing, insulation, electrical wiring, and exterior wall covering are the responsibility of the installer.
- Recommended ceiling height is 8 feet per manufacturer safety and clearance guidelines. For custom ceiling heights, contact our support team before ordering.
- Electrical installation must be performed by a licensed electrician in accordance with local building codes. Heater electrical requirements vary by model—confirm specifications with your electrician prior to purchase.
- Wall boards run horizontally by default. If room width exceeds 8 feet, an interior seam will be added where two boards meet to span the full width.
- Backrests are shipped flat. On-site spacers can be fabricated to achieve an angled pitch if preferred.
- Product photos may show a glass wall for reference; your shipment includes an all-glass door as described.
- This product is intended for indoor installation only.
Optional Heater Comparison
| Feature | Harvia Cilindro PC90 9KW | Harvia Cilindro PC90E 9KW | Harvia Virta 9KW | EOS Cubo Avantgarde 9KW | EOS Mythos S35 9KW |
|---|---|---|---|---|---|
| Product Image |  |
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| Power Output | 9 KW | 9 KW | 9 KW | 9 KW | 9 KW |
| Brand | Harvia | Harvia | Harvia | EOS | EOS |
| Control Type | Built-in Control | WiFi Control | WiFi Control | WiFi Control | WiFi Control |
| WiFi Connectivity | No | Yes | Yes | Yes | Yes |
| Heater Stones Included | Yes | Yes | Yes | Yes | Yes |
| Railing Included | No | No | Yes | No | No |
| Model Series | Cilindro | Cilindro | Virta | Cubo Avantgarde | Mythos |
| Remote Control | Manual only | App-based via WiFi | App-based via WiFi | App-based via WiFi | App-based via WiFi |
Harvia Cilindro PC90 9KW – Built-in Control
Harvia Cilindro PC90E 9KW – WiFi
Harvia Virta 9KW – WiFi + Railing
EOS Cubo Avantgarde 9KW – WiFi
EOS Mythos S35 9KW – WiFi
Heater Key Differences
Brands
- Harvia (Finnish): Cilindro PC90, PC90E, Virta — decades of sauna heritage
- EOS (German): Cubo Avantgarde, Mythos S35 — premium engineering with modern design
Control & Connectivity
- Cilindro PC90: Built-in manual control panel only
- Cilindro PC90E, Virta, EOS Cubo Avantgarde, EOS Mythos S35: WiFi-enabled for app-based scheduling and control
Included Accessories
- All heater options include heater stones
- Harvia Virta is the only model in this lineup that includes a protective safety railing
Frequently Asked Questions
What does this kit include?
The kit includes all interior sauna components: foil vapor barrier, tongue & groove wall and ceiling boards, bench boards with supports, corner moldings, duckboard flooring, an all-glass door with wood trim, upper and lower vent grills, backrests, a headrest, a sauna bucket with liner and ladle, a thermometer, and a marine-grade vapor-proof light. Detailed installation instructions are also included.
What do I need to supply that is not in the kit?
You are responsible for the structural framing, insulation, electrical wiring, and exterior wall covering. A licensed electrician is required for heater wiring. If you select a heater bundle, confirm the electrical requirements with your electrician before installation.
Can I order this kit without a heater?
Yes. Select "No Heater" in the Heater option at checkout. You can source and install a compatible heater separately, or contact our team for guidance on compatible models.
What is Thermo Poplar and why is it used?
Thermo Poplar is a sustainably sourced wood that has been thermally modified at approximately 374°F using a chemical-free process. This treatment improves dimensional stability and resistance to humidity and temperature fluctuations—properties that are important in a sauna environment. It also produces a warm, rich tone that complements the sauna aesthetic.
What ceiling height is required?
The recommended ceiling height is 8 feet, per manufacturer safety and clearance guidelines. If your space has a different ceiling height, please contact our support team before placing your order to discuss custom options.
What rough opening is needed for the door?
The included all-glass door requires a rough opening of 28″ × 80″. The door frame measures 27.2″ × 78.7″ (690 × 2000 mm) with a frame thickness of 1.65″ × 3.6″ (42 × 92 mm).
Which heater should I choose?
All heater options are 9KW and include heater stones. The Harvia Cilindro PC90 uses a built-in manual control. The PC90E, Harvia Virta, EOS Cubo Avantgarde, and EOS Mythos S35 all offer WiFi connectivity for app-based control. The Harvia Virta also includes a protective safety railing. See the heater comparison chart above for a full side-by-side breakdown.
Can this kit be used for commercial installations?
This kit is suitable for light commercial use such as boutique fitness studios or wellness centers. For larger commercial projects or multi-room installations, contact our team for a custom consultation.
The Carbon Smart™ 6′ × 9′ × 8′ Indoor Sauna Kit is a complete, well-specified package for anyone ready to add a permanent sauna room to their home or facility. Select your wood type, accessory package, and heater option above, and our team is available to answer any questions before you order.
Sauna use is a personal wellness practice. Consult a qualified healthcare provider before use if you have any medical conditions or concerns. This product is not intended to diagnose, treat, cure, or prevent any disease or medical condition.