The Carbon Smart™ Indoor Sauna Kit (7’ x 9’ x 8’) is a complete interior sauna package designed for homeowners and contractors who want a high-quality, custom-fit sauna without sourcing components separately. Built with thermally modified Thermo Poplar throughout, this kit arrives with all interior components precisely cut to your room dimensions. You supply the framing, insulation, electrical wiring, and exterior wall covering — we supply everything inside. Choose your accessory package and optional Harvia WiFi heater at checkout to configure the kit that fits your space and budget.
Why Customers Choose the Carbon Smart™ Sauna Kit
- Complete interior kit — all components are pre-cut to your room dimensions
- Thermo Poplar wood throughout: dimensionally stable, humidity-resistant, chemical-free treatment
- All-glass sauna door with wood handles and trim included
- Choice of accessory packages: bench skirting, LED under-bench lighting, or both
- Optional Harvia WiFi heater bundles available at checkout — no separate sourcing required
- Suitable for DIY installation or professional contractor builds
- Designed and supplied by Finnish Sauna Builders, specialists in custom indoor sauna systems
Product Highlights
Thermo Poplar Interior Wood
Thermo Poplar is a sustainably sourced wood thermally modified at approximately 374°F. The process — chemical-free — enhances dimensional stability and resistance to humidity and temperature fluctuations, producing a warm, rich tone well-suited to sauna environments.
Pre-Cut Interior Components
Every board, molding, and panel in this kit is cut to fit your 7’ x 9’ x 8’ room. You frame and insulate the space; the kit handles the interior finish from wall boards to ceiling to benches.
All-Glass Sauna Door
The included all-glass door features wood handles and trim, with a frame measuring 27.2” x 78.7” (690 x 2000 mm) and a required rough opening of 28” x 80”. It provides a clean, modern look while maintaining proper sauna heat retention.
Configurable Bench Layout
Bench configurations are available in multiple layouts shown in the product images. Each uses 20”-deep clear Thermo Poplar bench boards with supports, custom-built to your chosen configuration.
Optional Accessory Packages
Upgrade your kit with bench skirting for a finished look, LED under-bench lighting for ambiance, or the Luxury Package that includes both. All accessories are matched to the Thermo Poplar finish.
Optional Harvia WiFi Heater Bundles
Select a Harvia heater at checkout — Cilindro 11KW, Club 10KW, Virta 10.5KW, or Virta Combi 10.5KW — each with WiFi control and heater stones included. The Virta and Virta Combi models also include a safety railing.
What’s Included in the Kit
- Foil vapor barrier for moisture protection
- Ergonomic backrests
- 1x4 tongue-and-groove wall and ceiling boards in Thermo Poplar
- Clear 1x4 bench boards with supports (20” deep) in Thermo Poplar — custom-built to your chosen configuration
- Corner moldings for walls, ceiling, and baseboards in Thermo Poplar
- All-glass sauna door with wood handles and trim (frame: 27.2” x 78.7”; glass: 24.4” x 77.3”; rough opening: 28” x 80”)
- Duckboard flooring for walk area in Thermo Poplar
- Upper and lower vent grills for air circulation
- Traditional sauna bucket with liner and ladle
- Sauna thermometer
- Headrest
- Marine-grade, wall-mount, vapor-proof sauna light
- Detailed installation instructions
Framing, insulation, electrical wiring, and exterior wall covering are not included and must be supplied on-site.
Specifications
| Room Dimensions | 7’ x 9’ x 8’ (W x D x H) |
|---|---|
| Recommended Ceiling Height | 8 feet |
| Interior Wood | Thermo Poplar (thermally modified, chemical-free) |
| Wall & Ceiling Boards | 1x4 tongue-and-groove, horizontal run (seam added if width exceeds 8 ft) |
| Bench Depth | 20 inches |
| Door Frame Size | 27.2” x 78.7” (690 x 2000 mm) |
| Door Glass Size | 24.4” x 77.3” (620 x 1963 mm) |
| Door Frame Thickness | 1.65” x 3.6” (42 x 92 mm) |
| Rough Opening Required | 28” x 80” |
| Wood Type Option | Thermo Poplar |
| Accessory Options | No Accessories / Bench Skirting / LED Under-Bench Lighting / Luxury Package (Skirting + LED) |
| Heater Options | No Heater / Harvia Cilindro 11KW WiFi / Harvia Club 10KW WiFi / Harvia Virta 10.5KW WiFi / Harvia Virta Combi 10.5KW WiFi |
| Shipping Weight | 800 lbs |
| Product Type | Custom Indoor Sauna Kit |
| Vendor | Finnish Sauna Builders |
Heater Option Comparison
All heater options below include WiFi connectivity, app-based remote control, and heater stones. Select the model that best matches your sauna room size and feature preferences.
| Feature | Harvia Cilindro 11KW | Harvia Club 10KW | Harvia Virta 10.5KW | Harvia Virta Combi 10.5KW |
|---|---|---|---|---|
| Power Output | 11 kW | 10 kW | 10.5 kW | 10.5 kW |
| WiFi Control | Yes | Yes | Yes | Yes |
| Heater Stones Included | Yes | Yes | Yes | Yes |
| Safety Railing Included | No | No | Yes | Yes |
| Combi Steam Function | No | No | No | Yes |
| Design Series | Cilindro (cylindrical) | Club (floor-standing) | Virta (wall-mount) | Virta Combi (wall-mount) |
| Remote Control | App-based via WiFi | App-based via WiFi | App-based via WiFi | App-based via WiFi |
Key Differences at a Glance
- Highest output: Harvia Cilindro at 11 kW — best suited for the largest rooms in this size range
- Commercial-grade floor-standing design: Harvia Club at 10 kW
- Wall-mounted with safety railing: Harvia Virta at 10.5 kW
- Combined dry sauna and steam function: Harvia Virta Combi at 10.5 kW — the only model with an integrated steam generator
- All four models include WiFi app control, scheduling, and heater stones
Ideal For
- Homeowners building a dedicated indoor sauna room in a basement, spare room, or addition
- DIY builders who want pre-cut, matched components without custom fabrication
- Contractors outfitting residential or light commercial sauna spaces
- Buyers who want a complete interior kit with the option to add a WiFi-controlled heater in one order
- Those who prefer thermally modified, sustainably sourced wood for their sauna interior
Important Information
- Framing, insulation, electrical, and exterior finish not included. This kit supplies all interior sauna components. The structural shell, insulation, wiring, and exterior wall covering must be provided on-site.
- Recommended ceiling height is 8 feet. For custom ceiling heights, contact the Finnish Sauna Builders support team before ordering.
- 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 width.
- Door ships as all-glass. Some product photos may show a glass wall for reference; the included door is the all-glass model with wood handles and trim.
- Backrests ship flat. If an angled backrest is preferred, additional spacers can be created on-site to achieve the desired pitch.
- Heater installation requires a licensed electrician. If a heater option is selected, all electrical work must be performed by a qualified professional in accordance with local codes.
- Heater sizing: All optional heater models are rated for rooms larger than this kit’s 7’ x 9’ x 8’ footprint. Confirm compatibility with your specific room construction before selecting a heater.
- Contact Finnish Sauna Builders before ordering if you have questions about bench configuration, ceiling height, or heater selection.
Frequently Asked Questions
What does the Carbon Smart™ sauna kit include?
The kit includes all interior sauna components: foil vapor barrier, tongue-and-groove wall and ceiling boards, bench boards and supports, corner moldings, duckboard flooring, vent grills, an all-glass sauna door with wood handles and trim, ergonomic backrests, a headrest, a sauna bucket with liner and ladle, a thermometer, a vapor-proof sauna light, and installation instructions. Framing, insulation, electrical wiring, and exterior wall covering are not 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. If you select a heater option, a licensed electrician must install the heater and dedicated electrical circuit in accordance with local codes.
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 and resistance to humidity and temperature changes — properties that make it well-suited for the high-heat, high-humidity environment of a sauna interior. It also produces a warm, rich tone.
Can I choose a different bench configuration?
Yes. Multiple bench configurations are available and shown in the product images. Each configuration uses 20”-deep clear Thermo Poplar bench boards custom-built to your chosen layout. Select your preferred configuration at checkout or contact Finnish Sauna Builders for guidance.
What are the accessory package options?
There are four accessory options: No Accessories (kit only), Bench Skirting (adds a finished panel below the benches), LED Under-Bench Lighting (adds ambient lighting beneath the benches), and the Luxury Package which includes both bench skirting and LED under-bench lighting.
Which heater should I choose for this sauna size?
All four heater options — Harvia Cilindro 11KW, Club 10KW, Virta 10.5KW, and Virta Combi 10.5KW — are rated for rooms larger than this kit’s 7’ x 9’ x 8’ footprint. The right choice depends on your room’s insulation, ceiling construction, and personal preferences. The Virta Combi is the only model with an integrated steam function. Contact Finnish Sauna Builders if you need help selecting the right heater.
Is this kit suitable for DIY installation?
Yes. The Carbon Smart™ kit is designed for both DIY enthusiasts and professional contractors. Detailed installation instructions are included. Electrical work for any heater must be performed by a licensed electrician regardless of who installs the sauna interior.
What is the required rough opening for the sauna door?
The included all-glass sauna door requires a rough opening of 28” x 80”. The door frame measures 27.2” x 78.7” (690 x 2000 mm) and the glass panel measures 24.4” x 77.3” (620 x 1963 mm).
Can I order a custom ceiling height?
The standard recommended ceiling height is 8 feet per manufacturer safety and clearance guidelines. For custom ceiling heights, contact the Finnish Sauna Builders support team before placing your order.
The Carbon Smart™ 7’ x 9’ x 8’ Indoor Sauna Kit is a well-organized, complete interior package for anyone building a home sauna with quality materials and a clean finish. If you have questions about configuration, heater selection, or installation requirements, contact Finnish Sauna Builders before ordering — the team is available to help you get the right setup the first time.
This product is a sauna room kit intended for use as a personal wellness space. It is not a medical device and is not intended to diagnose, treat, cure, or prevent any health condition. Consult a qualified healthcare provider before use if you have any medical concerns.