The Carbon Smart™ Indoor Sauna Kit (6' × 6' × 8') is a complete, pre-cut sauna interior package designed for installation in a standard framed room. Built with thermally modified Thermo Poplar wood, it delivers lasting dimensional stability, natural moisture resistance, and a clean, warm aesthetic. Select your accessory package and optional 8 kW Harvia electric heater at checkout, and receive everything needed to finish your sauna interior — precisely cut and ready to install.
Why Customers Choose the Carbon Smart Sauna Kit
- All interior components arrive pre-cut to your 6' × 6' × 8' room dimensions — no guesswork, no waste
- Thermo Poplar wood is thermally modified without chemicals for enhanced stability and humidity resistance
- Responsibly sourced wood supports carbon-smart forestry practices
- All-glass sauna door included — no separate door purchase required
- Optional 8 kW Harvia electric heater bundles available at checkout for a single-order setup
- Configurable accessory packages: bench skirting, LED under-bench lighting, or both
- Suitable for residential and light commercial installations
- Detailed installation instructions included for DIY and contractor builds
Product Highlights
Thermo Poplar Interior Wood
Thermally modified at approximately 374°F using a chemical-free process, Thermo Poplar offers improved dimensional stability, reduced moisture absorption, and a warm, rich tone that holds up through repeated heat cycles.
Pre-Cut to Your Room Dimensions
Wall boards, ceiling boards, bench boards, and trim pieces are cut to fit your 6' × 6' × 8' room before shipping, reducing installation time and on-site cutting.
All-Glass Sauna Door Included
The kit includes a full all-glass door with wood handles and trim. The rough opening required is 28" × 80", and the frame measures 27.2" × 78.7" (690 × 2000 mm).
Configurable Accessory Packages
Select from No Accessories, Bench Skirting, LED Under-Bench Lighting, or the Luxury Package (Skirting + LED Lighting) to match your finish preferences and budget.
Optional 8 kW Harvia Electric Heater Bundles
Add a Harvia 8 kW electric heater — including models with built-in controls or WiFi app connectivity — directly at checkout. All heater options include sauna stones.
Marine-Grade Vapor-Proof Lighting
A wall-mount, marine-grade, vapor-proof sauna light is included in every kit, rated for the high-humidity sauna environment.
Proper Ventilation Components
Upper and lower vent grills are included to support correct air circulation, an important factor in sauna performance and longevity.
Specifications
| Room Dimensions | 6' × 6' × 8' (W × L × H) |
|---|---|
| Wood Species | Thermo Poplar (thermally modified, chemical-free) |
| Wall & Ceiling Boards | 1×4 tongue & groove, Thermo Poplar |
| Bench Boards | Clear 1×4, 20" deep, Thermo Poplar — custom-cut to configuration |
| 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" |
| Recommended Ceiling Height | 8 ft (per manufacturer safety guidelines) |
| Wall Board Direction | Horizontal (standard); interior seam added if room width exceeds 8 ft |
| Accessory Options | No Accessories / Bench Skirting / LED Under-Bench Lighting / Luxury Package |
| Heater Options | No Heater / Harvia KIP80B / KIP80W / Cilindro PC80 / Cilindro PC80E / Spirit / Virta (all 8 kW) |
| Shipping Weight | Approx. 800 lbs |
| Vendor | Finnish Sauna Builders |
What's Included in Every Kit
- Foil vapor barrier
- Ergonomic backrests (shipped flat; angled pitch achievable with on-site spacers)
- 1×4 tongue & groove wall and ceiling boards — Thermo Poplar
- Clear 1×4 bench boards with supports (20" deep) — Thermo Poplar, cut to your configuration
- Corner moldings for walls, ceiling, and baseboards — Thermo Poplar
- All-glass sauna door with wood handles and trim
- 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
Note: Framing, insulation, electrical wiring, and exterior wall covering are not included and must be supplied by the installer. Some product photos may show a glass wall for reference; the kit ships with an all-glass door.
Optional Harvia 8 kW Heater Comparison
All heater options are 8 kW and include sauna stones. Select the model that fits your control preference and budget.
| Model | Series | Control Type | WiFi | Railing Included |
|---|---|---|---|---|
| Harvia KIP80B | KIP | Built-in (manual) | No | No |
| Harvia Cilindro PC80 | Cilindro | Built-in (manual) | No | No |
| Harvia KIP80W | KIP | WiFi (app-based) | Yes | No |
| Harvia Cilindro PC80E | Cilindro | WiFi (app-based) | Yes | No |
| Harvia Spirit 8KW | Spirit | WiFi (app-based) | Yes | No |
| Harvia Virta 8KW | Virta | WiFi (app-based) | Yes | Yes |
Ideal For
- Homeowners building a dedicated indoor sauna room in a basement, spare room, or addition
- DIY builders who want pre-cut materials and clear installation instructions
- Contractors sourcing complete sauna interior packages for residential clients
- Spas, gyms, and wellness facilities requiring a durable, professionally finished sauna interior
- Buyers who want to select their own heater or add an 8 kW Harvia unit as a bundled option
Important Information
- This kit supplies interior sauna components only. Framing, insulation, electrical wiring, and exterior wall covering must be provided by the installer.
- Recommended ceiling height is 8 feet per manufacturer safety and clearance guidelines. For custom ceiling heights, contact the vendor before ordering.
- If a heater is selected, electrical installation must be performed by a licensed electrician in compliance with local building codes and the heater manufacturer's specifications.
- Wall boards run horizontally by default. If room width exceeds 8 feet, an interior seam will be added where boards meet to span the full width.
- Backrests are shipped flat. If an angled backrest is preferred, additional spacers can be fabricated on-site to achieve the desired pitch.
- The kit ships with an all-glass door. Some product images may show a glass wall panel for reference purposes only.
- Do not use this sauna kit for any purpose other than its intended use as a residential or light commercial sauna interior.
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 and supports, corner moldings, an all-glass door with wood handles and trim, duckboard flooring, upper and lower vent grills, a sauna bucket with liner and ladle, a thermometer, a headrest, a marine-grade vapor-proof light, and installation instructions. Framing, insulation, electrical wiring, and exterior wall covering are not included.
Do I need to supply the framing and insulation?
Yes. This kit provides the interior finish components only. You or your contractor will need to supply and install the structural framing, insulation, vapor barrier backing, electrical wiring, and any exterior wall covering before installing the kit components.
Can I add a heater to my order?
Yes. Six Harvia 8 kW electric heater options are available as add-ons at checkout, ranging from basic built-in controls to WiFi-enabled models with app-based scheduling. All heater options include sauna stones. If you prefer to source your own heater separately, select "No Heater" at checkout.
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 the wood's dimensional stability, reduces its tendency to absorb moisture, and gives it a warm, rich tone. It is well-suited for the high-heat, high-humidity environment of an indoor sauna.
What rough opening does the door require?
The included all-glass door requires a rough opening of 28" × 80". The door frame measures 27.2" × 78.7" (690 × 2000 mm) and the glass panel measures 24.4" × 77.3" (620 × 1963 mm). Frame thickness is 1.65" × 3.6" (42 × 92 mm).
Can I use a custom ceiling height?
The standard kit is designed for an 8-foot ceiling height, which is the manufacturer's recommended height for safety and clearance. If your space has a different ceiling height, contact the vendor before placing your order to discuss custom options.
What accessory packages are available?
Four accessory options are available at checkout: No Accessories, Bench Skirting, LED Under-Bench Lighting, and the Luxury Package which includes both Bench Skirting and LED Under-Bench Lighting.
What is the difference between the Cilindro PC80 and Cilindro PC80E heaters?
Both are 8 kW Harvia Cilindro Series heaters with a cylindrical design and large stone capacity, and both include sauna stones. The PC80 uses a built-in manual control panel. The PC80E adds WiFi connectivity, allowing you to control and schedule the heater remotely via a smartphone app.
Is this kit suitable for commercial use?
The Carbon Smart kit is designed for residential use and light commercial applications such as spas and fitness facilities. For high-traffic commercial installations, contact the vendor to confirm suitability and discuss any additional requirements.
The Carbon Smart Indoor Sauna Kit (6' × 6' × 8') gives you a complete, pre-cut interior package built from quality Thermo Poplar wood, with the flexibility to configure your accessories and 8 kW heater in a single order. If you have questions about sizing, installation, or heater selection, our team is available to help you plan the right setup for your space.
Sauna use may not be suitable for everyone. Consult a qualified healthcare provider before use if you have a medical condition, are pregnant, or are taking medications. This product is not intended to diagnose, treat, cure, or prevent any disease or medical condition.