The Carbon Smart™ Indoor Sauna Kit (7’ x 7’ 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 8kW heater at checkout to configure the kit that fits your space and budget.
Why Customers Choose the Carbon Smart™ 7x7x8 Sauna Kit
- Complete interior kit — all components are pre-cut to your 7’ x 7’ x 8’ 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
- Six optional Harvia 8kW heater bundles available at checkout — built-in control or WiFi models
- 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 using a chemical-free process. The treatment 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 7’ 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
Multiple bench configurations are available and shown in the product images. Each uses 20”-deep clear Thermo Poplar bench boards with supports, custom-built to your chosen layout.
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.
Six Optional Harvia 8kW Heater Bundles
Select from six Harvia 8kW heater options at checkout — ranging from built-in control models (KIP80B, Cilindro PC80) to WiFi-enabled models (KIP80W, Cilindro PC80E, Spirit, Virta) — each with heater stones included. The Virta also includes 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 7’ 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 KIP80B 8kW / Harvia Cilindro PC80 8kW / Harvia KIP80W 8kW WiFi / Harvia Cilindro PC80E 8kW WiFi / Harvia Spirit 8kW WiFi / Harvia Virta 8kW WiFi with Railing |
| Shipping Weight | 800 lbs |
| Product Type | Custom Indoor Sauna Kit |
| Vendor | Finnish Sauna Builders |
Heater Option Comparison
All heater options include heater stones. WiFi models add app-based remote control and scheduling. Select the model that best matches your control preferences and budget.
| Feature | KIP80B 8kW | Cilindro PC80 8kW | KIP80W 8kW WiFi | Cilindro PC80E 8kW WiFi | Spirit 8kW WiFi | Virta 8kW WiFi |
|---|---|---|---|---|---|---|
| Power Output | 8 kW | 8 kW | 8 kW | 8 kW | 8 kW | 8 kW |
| Control Type | Built-in | Built-in | WiFi | WiFi | WiFi | WiFi |
| WiFi / App Control | No | No | Yes | Yes | Yes | Yes |
| Heater Stones Included | Yes | Yes | Yes | Yes | Yes | Yes |
| Safety Railing Included | No | No | No | No | No | Yes |
| Design Series | KIP (wall-mount) | Cilindro (cylindrical) | KIP (wall-mount) | Cilindro (cylindrical) | Spirit | Virta (wall-mount) |
| Remote Control | Manual only | Manual only | App-based | App-based | App-based | App-based |
Key Differences at a Glance
- All six models share the same 8 kW output and include heater stones
- Built-in control (no WiFi): Harvia KIP80B and Cilindro PC80 — straightforward manual operation
- WiFi app control: Harvia KIP80W, Cilindro PC80E, Spirit, and Virta — remote temperature and timer management via smartphone
- Cylindrical design with large stone capacity: Cilindro PC80 and PC80E
- Safety railing included: Harvia Virta only — the only model in this lineup with a protective railing
- Premium WiFi wall-mount: Harvia Spirit and Virta offer modern aesthetics with full app connectivity
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 heater in one order
- Those who prefer thermally modified, sustainably sourced wood for their sauna interior
- Buyers choosing between a simple built-in control heater and a WiFi-enabled model
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.
- WiFi heater models require a home WiFi network for app-based control. Built-in control models (KIP80B, Cilindro PC80) operate via the on-unit panel only.
- 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™ 7x7x8 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 thermally modified at approximately 374°F using a chemical-free process. This treatment improves 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.
What is the difference between the built-in control and WiFi heater options?
The Harvia KIP80B and Cilindro PC80 use a built-in control panel on the heater unit itself — no remote or app access. The KIP80W, Cilindro PC80E, Spirit, and Virta models connect to your home WiFi network and can be controlled via the Harvia app on your smartphone, including remote temperature setting and session scheduling.
Which heater option includes a safety railing?
Only the Harvia Virta 8kW WiFi option includes a protective safety railing. All other heater options in this lineup do not include a railing. If a railing is required for your installation, select the Virta option or purchase a compatible railing separately.
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.
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 7’ 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. Whether you want a simple built-in control heater or a fully WiFi-connected model, the options at checkout let you configure the right kit without sourcing components from multiple suppliers. Contact Finnish Sauna Builders before ordering if you have questions about configuration, heater selection, or installation requirements.
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.