The Carbon Smart 5' x 8' x 8' Indoor Sauna Kit gives you everything needed to finish the interior of a residential sauna room — precisely cut and ready to install. Built with Thermo Poplar, a thermally modified wood chosen for its dimensional stability and resistance to the heat and humidity of a sauna environment, this kit is designed for homeowners and contractors who want quality materials without sourcing components separately. You supply the framing, insulation, electrical wiring, and exterior wall covering; we supply the rest. Choose your preferred heater and accessory package at checkout to configure the kit for your space.
Why Customers Choose the Carbon Smart Sauna Kit
- Complete interior kit — all components precisely cut to your room dimensions
- Thermo Poplar wood: thermally modified, chemical-free, and sustainably sourced
- All-glass sauna door with wood handles and trim included
- Marine-grade vapor-proof sauna light included
- Traditional sauna bucket, ladle, thermometer, and headrest included
- Choice of six Harvia 8kW electric heater options at checkout
- Optional accessory packages: bench skirting, LED under-bench lighting, or both
- Detailed installation instructions included for DIY or contractor builds
Product Highlights
Thermo Poplar Wood Interior
All wall boards, ceiling boards, bench boards, moldings, and flooring are made from Thermo Poplar — a wood thermally modified at approximately 374°F through a chemical-free process. This treatment improves dimensional stability and resistance to humidity and temperature fluctuations, making it well-suited for sauna interiors.
All-Glass Sauna Door Included
The kit includes an all-glass sauna door with wood handles and trim. The door frame measures 27.2" x 78.7" (690 x 2000 mm) and requires a rough opening of 28" x 80".
Configurable Heater Options
Select from six Harvia 8kW electric heater options at checkout, ranging from built-in control models to WiFi-enabled heaters with app-based scheduling. All heater options include sauna stones.
Accessory Packages Available
Customize your kit with optional bench skirting, LED under-bench lighting, or the Luxury Package that includes both. Select your preference at checkout.
Marine-Grade Vapor-Proof Lighting
A wall-mount, marine-grade, vapor-proof sauna light is included with every kit — rated for the heat and humidity conditions of a sauna room.
Foil Vapor Barrier Included
A foil vapor barrier is included to provide proper moisture protection between the sauna interior and the surrounding structure.
Sustainably Sourced Wood
As part of the Carbon Smart line, the Thermo Poplar used in this kit is responsibly sourced to support carbon-smart forestry practices.
Specifications
| Room Dimensions | 5' x 8' x 8' (W x L x H) |
| Recommended Ceiling Height | 8 feet |
| Wood Species | Thermo Poplar (thermally modified) |
| Wall and Ceiling Boards | 1x4 tongue and groove, Thermo Poplar |
| Bench Boards | Clear 1x4, 20" deep, Thermo Poplar |
| Door Frame Dimensions | 27.2" x 78.7" (690 x 2000 mm) |
| Door Glass Dimensions | 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" |
| Wall Board Direction | Horizontal (standard); interior seam added if room width exceeds 8 ft |
| Heater Options | No Heater, or choice of six Harvia 8kW models (see Heater Comparison below) |
| Accessory Options | No Accessories, Bench Skirting, LED Under Bench Lighting, or Luxury Package (both) |
| Shipped Weight | 800 lbs |
| Vendor | Finnish Sauna Builders |
What's Included in the Kit
- Foil vapor barrier for moisture protection
- Ergonomic backrests
- 1x4 tongue and groove boards for walls and ceiling (Thermo Poplar)
- Clear 1x4 bench boards with supports, 20" deep (Thermo Poplar) — custom-built to your chosen bench 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 for air circulation
- Traditional sauna bucket with liner and ladle
- Sauna thermometer
- Comfortable headrest
- Marine-grade, wall-mount, vapor-proof sauna light
- Detailed installation instructions
Heater and accessory packages are selected at checkout and shipped as part of your order where applicable.
Heater Option Comparison
All heater options are Harvia 8kW electric models. Sauna stones are included with every heater option. Select your preferred model at checkout.
| Model | Series | Control Type | WiFi | Stones Included | Railing Included |
|---|---|---|---|---|---|
| Harvia KIP80B | KIP Series | Built-in Control | No | Yes | No |
| Harvia Cilindro PC80 | Cilindro Series | Built-in Control | No | Yes | No |
| Harvia KIP80W | KIP Series | WiFi Control | Yes | Yes | No |
| Harvia Cilindro PC80E | Cilindro Series | WiFi Control | Yes | Yes | No |
| Harvia Spirit | Spirit Series | WiFi Control | Yes | Yes | No |
| Harvia Virta | Virta Series | WiFi Control | Yes | Yes | Yes |
KIP Series (KIP80B and KIP80W)
Compact wall-mounted design. The KIP80B uses a built-in manual control panel. The KIP80W adds WiFi connectivity for app-based control and scheduling.
Cilindro Series (PC80 and PC80E)
Cylindrical design with a large stone capacity. The PC80 uses a built-in control panel. The PC80E adds WiFi connectivity for remote control via smartphone.
Harvia Spirit
Modern aesthetic with WiFi connectivity and app-based control. Heater stones included.
Harvia Virta (with Safety Railing)
WiFi-enabled with app-based control. The only heater option in this kit that includes a protective safety railing. Heater stones included.
Ideal For
- Homeowners building a new indoor sauna room from scratch
- Contractors and DIY builders who want pre-cut, ready-to-install interior components
- Those who prefer to source framing, insulation, and electrical separately
- Customers who want to select their own heater model and accessory configuration
- Residential sauna rooms with an 8-foot ceiling height
Important Information
- This kit supplies interior sauna components only. Framing, insulation, electrical wiring, and exterior wall covering are not included and must be supplied separately.
- Recommended ceiling height is 8 feet per manufacturer safety and clearance guidelines. Contact Finnish Sauna Builders for custom ceiling height requirements 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.
- The kit includes an all-glass door. Some product images may show a glass wall for reference — your shipment will include the all-glass door as described.
- Backrests are shipped flat. If an angled backrest is preferred, additional spacers can be created on-site to achieve the desired pitch.
- If a heater is selected, electrical installation must be performed by a licensed electrician in accordance with local codes. All Harvia heater options require a dedicated 240V electrical circuit.
- Bench configurations are custom-built to your chosen layout. Review the configuration options in the product images before ordering.
- Contact Finnish Sauna Builders before ordering if you have questions about room dimensions, ceiling height, or heater sizing for your specific space.
Frequently Asked Questions
What does this kit include?
The kit includes all interior sauna components: tongue and groove wall and ceiling boards, bench boards and supports, corner moldings, duckboard flooring, an all-glass sauna door with wood handles and trim, a foil vapor barrier, upper and lower vent grills, ergonomic backrests, a headrest, a sauna bucket with liner and ladle, a sauna thermometer, a marine-grade vapor-proof light, and detailed installation instructions. Heater and accessory packages are selected separately at checkout.
What do I need to supply that is not included?
You supply the framing, insulation, electrical wiring, and exterior wall covering. Everything needed for the sauna interior is included in the kit.
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 through a chemical-free process. This treatment improves the wood's dimensional stability and resistance to humidity and temperature fluctuations — properties that make it well-suited for sauna interiors. It also produces a warm, rich tone.
Can I choose my heater?
Yes. You can select from six Harvia 8kW electric heater options at checkout, or choose "No Heater" if you plan to source a heater separately. All heater options include sauna stones. See the Heater Option Comparison section above for details on each model.
What accessory packages are available?
You can add bench skirting, LED under-bench lighting, or the Luxury Package (which includes both) at checkout. You can also select "No Accessories" if you prefer the standard kit.
What ceiling height does this kit require?
The recommended ceiling height is 8 feet per manufacturer safety and clearance guidelines. If your space has a different ceiling height, contact Finnish Sauna Builders before ordering to discuss options.
What rough opening does the sauna door require?
The 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).
Which heater option includes a safety railing?
Only the Harvia Virta 8kW WiFi option includes a protective safety railing. All other heater options do not include a railing, though one may be added separately if required by local code.
Is this kit suitable for commercial use?
This kit is designed primarily for residential use. Contact Finnish Sauna Builders to discuss commercial applications and whether this kit meets the requirements for your project.
The Carbon Smart 5' x 8' x 8' Indoor Sauna Kit is a well-specified, configurable package for homeowners and contractors who want quality interior components without the complexity of sourcing materials individually. Select your wood type, heater, and accessory package at checkout, and our team will follow up to coordinate delivery and answer any pre-installation questions.