The ThermaSol Fortis is a fully assembled, pre-wired 4-person outdoor sauna cabin built for year-round use. Its contemporary design pairs an 8mm Parsol dark grey tinted glass facade with aluminum framing and hidden hinges on the exterior, and brushed thermo spruce walls with thermo aspen benches on the interior. Heat is delivered by a Harvia Virta electric heater, managed via the Harvia Xenio control system, and retained by multi-layer wood fiber insulation and a heavy-duty Firestone EPDM roof. Integrated RGB LED lighting completes the interior environment. Made to order and delivered fully assembled with pre-wired electrical systems, the Fortis is ready for connection upon arrival. Lead time is 12 to 13 weeks. Free USA shipping included.
Why Customers Choose the ThermaSol Fortis
- Fully assembled and pre-wired — no major on-site construction required
- 8mm Parsol dark grey tinted glass facade for solar protection and privacy
- Harvia Virta electric heater with Harvia Xenio advanced control system
- Heavy-duty Firestone EPDM roof for all-season weather protection
- Multi-layer wood fiber insulation for energy-efficient heat retention year-round
- Thermo aspen benches — moisture-resistant and dimensionally stable
- Brushed thermo spruce interior walls for a refined natural wood finish
- Integrated RGB LED lighting for customizable session ambiance
- Contemporary eave-style roofline with modern architectural design
- Free USA shipping
Product Highlights
Fully Assembled & Pre-Wired
The Fortis arrives fully assembled with pre-wired electrical systems, eliminating the need for on-site cabin construction. Installation requires a suitable electrical connection by a licensed electrician — once connected, the cabin is ready for use.
8mm Parsol Dark Grey Glass Facade
The front-facing facade features 8mm Parsol dark grey tinted glass with aluminum framing and hidden hinges, providing solar protection and privacy while giving the cabin a clean, contemporary exterior appearance.
Harvia Virta Heater & Harvia Xenio Controls
The Harvia Virta electric heater delivers consistent, high-performance heat output. It is managed via the Harvia Xenio advanced control system, which provides precise temperature and session management from an intuitive interface.
Firestone EPDM Roof
The heavy-duty Firestone EPDM rubber roof is designed for long-term outdoor durability across all seasons, providing reliable weather protection for the cabin structure and insulation system.
Multi-Layer Wood Fiber Insulation
The eco-friendly multi-layer wood fiber insulation is engineered to retain heat effectively throughout the year, supporting consistent sauna temperatures while minimizing energy consumption during each session.
Thermo Spruce & Thermo Aspen Interior
The interior walls are finished in brushed thermo spruce, and the benches are constructed from thermo aspen — a heat-treated wood selected for its moisture resistance and dimensional stability in high-heat, high-humidity sauna conditions.
Integrated RGB LED Lighting
Built-in RGB LED lighting allows you to select from a range of colors to customize the visual atmosphere of each session. Lighting controls are integrated into the cabin's interior.
Contemporary Eave-Style Roofline
The modern eave-style roofline creates a slight overhang that frames the cabin's exterior and contributes to its architectural presence in outdoor settings such as gardens, patios, and dedicated wellness areas.
Specifications
| Model | ThermaSol Fortis |
| Capacity | 4 Person |
| Use | Outdoor |
| Assembly | Fully assembled and pre-wired |
| Exterior Facade | 8mm Parsol dark grey tinted glass, aluminum framing, hidden hinges |
| Roofline Style | Contemporary eave style |
| Roof Material | Firestone EPDM (heavy-duty rubber) |
| Exterior Wood | Nordic thermo spruce and pinewood |
| Interior Wall Finish | Brushed thermo spruce |
| Bench Material | Thermo aspen |
| Insulation | Multi-layer wood fiber (eco-friendly) |
| Heater | Harvia Virta Electric Heater |
| Control System | Harvia Xenio |
| Lighting | Integrated RGB Color LED |
| Lead Time | Made to order — 12 to 13 weeks |
| Shipping | Free USA shipping |
| SKU | 14-FORTIS |
| Full Dimensions & Electrical Specs | See manufacturer spec sheet or contact us before purchasing |
Ideal For
- Homeowners adding a premium outdoor sauna to a garden, patio, or backyard wellness area
- Those who want a fully assembled, ready-to-connect sauna without on-site construction
- Year-round outdoor sauna use in varying climates
- Buyers seeking a design-forward outdoor cabin with a contemporary glass and wood aesthetic
- Households of up to four people sharing a dedicated outdoor wellness space
- Long-term outdoor installations where weather durability and build quality are priorities
Important Information
- This is a made-to-order product with a lead time of 12 to 13 weeks from order confirmation. Plan your purchase and site preparation timeline accordingly.
- The Fortis arrives fully assembled and pre-wired. A licensed electrician must complete the final electrical connection at your installation site. Verify that your site meets the heater's voltage and amperage requirements before purchasing.
- Site preparation — including a level, load-bearing foundation or base — is the buyer's responsibility and must be completed before delivery. Contact us for site preparation guidance before ordering.
- Ensure the installation location provides adequate clearance around the cabin for ventilation, access, and local building code compliance. Check local permit requirements before installation.
- Do not leave the sauna unattended while in operation. Follow all heater and control system manufacturer instructions included with the unit.
- This product is intended for adult use. Keep children away from the sauna during operation.
- Review the full manufacturer spec sheet for complete dimensional and electrical specifications before finalizing your site plan. Contact us with any pre-purchase questions.
- Consult a qualified healthcare professional before use if you have any medical conditions, are pregnant, or are taking medications that may be affected by heat exposure.
Frequently Asked Questions
How long does it take to receive the ThermaSol Fortis?
The ThermaSol Fortis is a made-to-order product with a lead time of 12 to 13 weeks from order confirmation. Free USA shipping is included. Plan your site preparation to be complete before the delivery window.
Does the Fortis arrive fully assembled?
Yes. The Fortis is delivered fully assembled and pre-wired. Installation requires a licensed electrician to complete the final electrical connection at your site. No on-site cabin construction is required.
What heater and control system does the Fortis include?
The Fortis includes a Harvia Virta electric heater managed by the Harvia Xenio advanced control system. Full electrical specifications — including wattage and voltage requirements — are available in the manufacturer spec sheet.
What is the Parsol dark grey glass facade?
The front-facing facade features 8mm Parsol dark grey tinted glass with aluminum framing and hidden hinges. The tinted glass provides solar protection and privacy while giving the cabin a contemporary exterior appearance.
Is the Fortis suitable for year-round outdoor use?
Yes. The Fortis is designed for outdoor use across all seasons. The heavy-duty Firestone EPDM roof and multi-layer wood fiber insulation are selected for weather durability and year-round thermal performance.
Do I need to prepare a foundation before delivery?
Yes. A level, load-bearing foundation or base must be in place before the cabin is delivered. Site preparation is the buyer's responsibility. Contact us before ordering for guidance on foundation requirements.
What are the full dimensions of the Fortis?
Full interior and exterior dimensions are available in the manufacturer spec sheet. Please review the spec sheet or contact us before purchasing to confirm the Fortis will fit your intended installation site.
Are local permits required for outdoor sauna installation?
Permit requirements vary by location. We recommend checking with your local building authority before purchasing to confirm whether a permit is required for an outdoor sauna structure at your property.
The ThermaSol Fortis is a fully assembled, weather-ready outdoor sauna cabin built with quality materials — Harvia Virta heating, Harvia Xenio controls, an EPDM roof, thermo aspen benches, and a Parsol glass facade — in a design suited to modern outdoor living spaces. If you're planning a permanent outdoor sauna installation and want a complete, ready-to-connect solution, the Fortis is a well-specified option. Review the spec sheet, confirm your site is ready, and contact us with any questions before ordering.
This product is intended for general wellness and relaxation use. It is not a medical device and is not intended to diagnose, treat, cure, or prevent any medical condition. Consult a qualified healthcare professional before use if you have any health concerns.