Celsium Jonas Large garden sauna - comfortable and spacious
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🚚 Free shipping to EU mainland & Switzerland for orders over 300€
Spacious elegance – more room for shared moments
The Celsium Jonas Large Outdoor Sauna is the most spacious model in the Jonas series and can accommodate up to six Persons. It combines modern design with functional sophistication—perfect for families, friends, or wellness enthusiasts who value comfort and a sense of space. Its impressive glass front opens up a view of nature and creates an atmosphere of light, space, and relaxation.
Celsium Jonas Large Designer Sauna – Clear Forms, New Dimensions
With the Jonas Large, Celsium focuses on architectural clarity and generous lines. The minimalist design blends harmoniously into any environment and brings modern elegance to your garden or spa area.
The color palette, ranging from soft beige to deep ebony, gives the sauna its individual character. The patented design (EUIPO) stands for long-lasting quality and a well-thought-out, modular construction—developed for lasting stability and easy Installation.



Celsium Jonas Large Solid Wood Sauna – fine materials with character
The interior paneling is available in Scandinavian spruce, thermo pine, black alder, aspen, or premium thermo aspen. Each type of wood has its own texture, color nuance, and character—from classic Nordic to elegant and modern.
The exterior cladding is elaborately handcrafted and given weather-resistant, long-lasting protection with high-quality oils or varnishes. Thanks to 5 cm thick PIR insulation, the heat remains constant, while energy efficiency and climate comfort are at the highest level.
Celsium Jonas Large Glass Sauna – Transparency and light in perfection
The large glass front gives the Jonas Large a feeling of openness and tranquility. It is available in several versions—from clear glass to tinted or matte finishes to exclusive mirror glass (full or half mirror) or black Planibel glass.
The safety glass ensures durability and creates a harmonious balance between the interior and nature. The result is a luxurious wellness ambience with architectural lightness.

Celsium Jonas Large Wellness Cabin – new L-shaped bench design
The Jonas Large now features a redesigned L-shaped bench layout —developed for greater comfort, freedom of movement, and a more balanced sense of space.
The new design makes optimal use of the generous interior space while offering more headroom on the upper seating level, which is particularly comfortable for taller Persons. A small step leads to two ergonomically arranged seating steps that allow you to sit and lie down in a relaxed position.
The door and oven area remains unchanged – the new layout integrates harmoniously into the existing room concept at no extra cost.
Celsium Jonas Large Outdoor Sauna – Technology and Function in Harmony
The Jonas Large is fully insulated and designed for maximum energy efficiency. The door hinge can be mounted on either the left or right side.
The roof is made of rolled bitumen shingles as standard – durable, weatherproof, and perfectly matched to the overall look with their clear design language.
The modular design allows for easy Installation —precise, stable, and low-maintenance.
Experience generous warmth in a stylish ambience.
The Celsium Jonas Large Outdoor Sauna is a place of tranquility, togetherness, and well-being. Enjoy warmth, light, and space in perfect balance—designed to meet the highest standards of design, comfort, and quality.
🔶 Scope of delivery
Everything at a glance – this is what's included!
- Prefabricated sauna elements including insulation
- Interior paneling made from selected wood species
- L-shaped benches with a new room concept
- Glass front (clear glass, standard)
- Door (choice of left or right hinge)
- Roof with rolled bitumen shingles (standard equipment)
- Wooden floor with drainage channel
- Screw and assembly set
- Detailed assembly instructions

Customized sauna solutions for the highest standards
Are you planning something special and looking for a solution that fits your ideas perfectly?
Whether custom sizes, individual material requests, special color concepts, or technical adjustments—almost anything is possible.
Thanks to flexible manufacturing, even demanding special requests can be professionally realized—with the goal of creating a wellness experience that fits seamlessly into your living space.
Do you have a special idea?
- Feel free to contact us directly—we will advise you personally and work with you to develop your dream sauna.
Specifications
| Capacity | For up to 6 Persons |
| External dimensions (W × D × H) | 2.15 m × 2.74 m × 2.55 m |
| Interior dimensions | 1.95 m x 2.62 m x 2.40 m (after deduction of wall + bench) |
| Floor space | 5.9 m² |
| Weight | Approx. 820 kg |
| Wall construction |
Modular construction, 18 mm facade wood + 5 cm PIR insulation |
| Total wall thickness | approx. 14 cm |
| Interior paneling | Scandinavian spruce (standard) or thermo pine, black alder, aspen, thermo aspen |
| Benches | New L-shaped layout, lime (standard), optional black alder, thermo pine, or thermo aspen |
| Glas | Clear glass (standard), optionally tinted, frosted, or mirrored glass |
| Roof | Roll bitumen shingles (standard, no further options) |
| Tür | Hinge on the left or right |
| Floor | Wooden flooring, same wood type as interior walls |
| Construction | Patented (EUIPO), element-based construction |
| Insulation | Included in delivery |

Instructions: How to choose the right Sauna Heater for your Celsium Outdoor Sauna
The right Sauna Heater is crucial for the overall sauna experience—it influences the heat quality, heating time, and energy efficiency. To help you get the most out of your Celsium Outdoor Sauna, here is a concise and informative guide to choosing the right heater.
1. Calculate the room volume correctly
First, determine the interior volume of your sauna:
Width × Depth × Height = m³ (cubic meters)
Example for the Ula Micro: 1.35 m × 1.25 m × 2.30 m = approx. 3.9 m³
Important:
If your sauna has glass elements, thin exterior walls, or is freestanding in the garden, you should add approximately 1.5 m³ per square meter of uninsulated area. This so-called insulation reserve compensates for heat loss.
2. Choosing the right heating power
As a guideline:
1 kW heating capacity per 1 m³ room volume
- For 4 m³ → ideally a 4 kW heater
- For intermediate values, it is better to round up rather than down – so that your stove works reliably even at low outside temperatures.
3. Note the power connection
There are two variants depending on the model and performance:
- 230V connection (Schuko plug) for compact sauna heaters
- 400 V three-phase current (high-voltage current) for more powerful models
Note: The connection must always be carried out by a qualified electrician.
5. Controls & comfort functions
Modern control systems offer not only temperature control, but also timer functions, app control, and safety features:
- Manual: classic rotary control module
- Digital: external control unit with precise temperature control
- Smart: App control via Wi-Fi or 4G (e.g., HUUM UKU Wi-Fi)