The Carbon Smart™ Indoor Sauna Kit delivers a complete, professionally finished sauna room in a compact 5′ × 5′ × 8′ footprint—ideal for smaller spaces without compromising on quality. 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
- Compact 5′ × 5′ footprint fits smaller rooms, basements, and converted spaces
- Complete interior package—no sourcing individual components separately
- Thermo Poplar wood is thermally modified without chemicals for lasting stability
- Configurable bench layouts to fit your space and preference
- Optional 6KW Harvia heater bundles—add at checkout
- Optional accessory upgrades: bench skirting, LED under-bench lighting, or both
- Detailed installation instructions included for DIY or contractor builds
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 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 6KW Harvia Heater Bundles
Select a 6KW Harvia heater at checkout—choose from the KIP, Cilindro, Spirit, or Virta series. All heater options include heater stones. See the comparison chart below for a full side-by-side breakdown.
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 | 5′ × 5′ × 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) | 6KW – Harvia KIP60W, KIP60B, Cilindro PC60, Cilindro PC60E, Spirit, Virta |
| 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 with smaller rooms, bathrooms, or converted closet/utility spaces
- Basement, garage, or spare room conversions where space is limited
- DIY builders and contractors looking for precision-cut, ready-to-install components
- Residential wellness rooms and home gym additions
- 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. Both room dimensions (5 feet) are within the standard 8-foot board length, so no interior seam is required for this size.
- 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 KIP60W 6KW | Harvia KIP60B 6KW | Harvia Cilindro PC60 6KW | Harvia Cilindro PC60E 6KW | Harvia Spirit 6KW | Harvia Virta 6KW |
|---|---|---|---|---|---|---|
| Product Image |  |
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| Power Output | 6 KW | 6 KW | 6 KW | 6 KW | 6 KW | 6 KW |
| Brand | Harvia | Harvia | Harvia | Harvia | Harvia | Harvia |
| Control Type | WiFi Control | Built-in Control | Built-in Control | WiFi Control | WiFi Control | WiFi Control |
| WiFi Connectivity | Yes | No | No | Yes | Yes | Yes |
| Heater Stones Included | Yes | Yes | Yes | Yes | Yes | Yes |
| Railing Included | No | No | No | No | No | Yes |
| Model Series | KIP | KIP | Cilindro | Cilindro | Spirit | Virta |
| Remote Control | App-based via WiFi | Manual only | Manual only | App-based via WiFi | App-based via WiFi | App-based via WiFi |
Harvia KIP60W 6KW – WiFi
Harvia KIP60B 6KW – Built-in Control
Harvia Cilindro PC60 6KW – Built-in Control
Harvia Cilindro PC60E 6KW – WiFi
Harvia Spirit 6KW – WiFi
Harvia Virta 6KW – WiFi + Railing
Heater Key Differences
Control & Connectivity
- KIP60B and Cilindro PC60: Built-in manual control panel only—no app or remote features
- KIP60W, Cilindro PC60E, Spirit, and Virta: WiFi-enabled for app-based scheduling and control
Design & Series
- KIP Series: Compact wall-mounted design, available in WiFi (KIP60W) and built-in control (KIP60B) versions
- Cilindro Series: Cylindrical design with large stone capacity, available in standard (PC60) and WiFi (PC60E) versions
- Spirit Series: Modern aesthetic with WiFi connectivity
- Virta Series: Premium model with WiFi control and included protective safety railing
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 6KW and include heater stones. The KIP60B and Cilindro PC60 use built-in manual controls. The KIP60W, Cilindro PC60E, Spirit, and Virta are WiFi-enabled for app-based control. The Harvia Virta is the only model that includes a protective safety railing. See the heater comparison chart above for a full side-by-side breakdown.
Is this kit suitable for a small bathroom or utility room conversion?
The 5′ × 5′ footprint is one of the more compact sizes available and can work well in smaller dedicated spaces. The room must be properly framed, insulated, and ventilated per the installation instructions. Contact our team to discuss your specific space before ordering.
The Carbon Smart™ 5′ × 5′ × 8′ Indoor Sauna Kit is a complete, well-specified package for anyone ready to add a permanent sauna room to a smaller space. Select your 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.