Kohler C1 Graphite Grey 2-5 Person Indoor Sauna Kit
The Kohler C1 in Graphite Grey takes spa-quality sauna design and gives it a striking modern edge. The exterior is finished in deep Graphite Grey, transforming the cabin into an architectural statement piece sleek, refined, and unmistakably contemporary while the interior keeps the warm, welcoming character of premium Scandinavian spruce. Available in 2-, 3-, and 5-person configurations with freestanding or alcove installation, the C1 Graphite Grey adapts to your space rather than the other way around.
Graphite Grey exterior, premium spruce interior
The deep Graphite Grey exterior is built to integrate into modern interiors dark, sophisticated, and architectural in feel. Step inside and the atmosphere shifts entirely: warm, welcoming Scandinavian spruce walls and ceiling envelop the space. The obeche wood bench and matching backrest are paired with 2700K warm white indirect lighting positioned behind them soft, gentle illumination that doesn't fight with the heat for your attention. Tongue-and-groove walls and connections create a clean, seamless appearance throughout.
Built for serious heat retention
The C1 doesn't compromise on thermal performance. 0.3" tempered glass door and windows pair with 2.1" thick mineral wool insulation between the walls and rubber seals at every joint, locking heat in for consistent, long sessions. A FERO freestanding electric heater with sauna stones and a heater guard delivers traditional Finnish-style steam, while dual thermostatic control ensures every session is safe and repeatable.
Smart controls and ventilation done right
An externally mounted digital control panel handles temperature, session time, and backrest lighting no need to interrupt your session to adjust settings. The Aerotherm ventilation system maintains a steady supply of fresh oxygen and proper air exchange throughout your session, so the air stays breathable even at peak heat. Beech wood door handles stay cool to the touch, and the freestanding-or-alcove design works for almost any indoor layout.
Striking Graphite Grey exterior, premium Scandinavian spruce interior, FERO electric heater, and tempered glass detailing the Kohler C1 Graphite Grey brings architectural sauna design into modern homes. Available in 2-, 3-, and 5-person sizes with freestanding or alcove installation. Backed by Kohler's 150+ year heritage and 5-year limited warranty.
2, 3, or 5 person sizes Indoor use Graphite Grey exterior Scandinavian spruce interior FERO electric heater Tempered glass door & windows Freestanding or alcove 5-year limited warranty
Specifications
2-Person dimensions (K-39950)
| Width |
65-3/8" (1,661 mm) |
| Depth |
46-1/8" (1,172 mm) |
| Height |
83-1/2" (2,121 mm) |
| Capacity |
Up to 2 people |
3-Person dimensions (K-39951)
| Width |
77-3/16" (1,961 mm) |
| Depth |
54" (1,372 mm) |
| Height |
83-7/16" (2,119 mm) |
| Capacity |
Up to 3 people |
5-Person dimensions (K-39963)
| Width |
81-1/8" (2,061 mm) |
| Depth |
77-5/8" (1,972 mm) |
| Height |
83-1/2" (2,121 mm) |
| Capacity |
Up to 5 people |
Construction & materials
| Exterior finish |
Graphite Grey |
| Interior walls |
Premium Scandinavian spruce |
| Bench & backrest |
Obeche wood |
| Door & windows |
0.3" (8 mm) tempered glass |
| Door handle |
Beech wood (cool-touch) |
| Heater safety rail |
Obeche wood |
| Insulation |
2.1" (5.4 cm) mineral wool |
| Floor type |
Spruce or No Floor (option) |
| Lighting |
2700K warm white indirect |
| Ventilation |
Aerotherm system |
Electrical & heater
| Heater |
FERO freestanding electric |
| Heater fuel |
Electric |
| Heater voltage |
220–240V |
| Heater frequency |
50/60 Hz |
| Heater safety distance |
1.6" (4 cm) |
| Sauna room voltage |
240V |
| Cord length |
9' 10" (2.9 m) |
| Cord location |
Top rear |
| Control |
External digital panel |
Installation & clearance
| Installation method |
Freestanding or alcove |
| Wall clearance |
2" (5 cm) minimum |
| Ceiling clearance |
8' (2.4 m) minimum |
| Flooring |
Full Floor or No Floor (option) |
| Installation |
DIY or Professional |
2-Person (K-39950)
3-Person (K-39951)
5-Person (K-39963)
What's included
Front frame panels
Side wall panels
Rear wall panels
Ceiling elements
Bottom frame
Backrest
Benches
FERO electric sauna heater
Heater guard
Sauna stones
Digital control panel
Indirect lighting (2700K)
Wall-mounted thermometer
Beech 20-minute hourglass timer
Headrest
Stool
Installation hardware
Installation & operation manual
Why the Kohler C1 stands out
Premium Scandinavian spruce
Both interior and exterior built from premium spruce. Warm, welcoming atmosphere with the kind of grain and character only premium European softwood delivers.
FERO electric heater
Freestanding FERO heater with sauna stones and heater guard provides traditional Finnish-style heat. Reliable, efficient, and built for daily residential use.
Indirect 2700K lighting
Warm white indirect lighting positioned behind the backrest creates a gentle, relaxing atmosphere — never harsh, never distracting from the experience.
Aerotherm ventilation
Engineered ventilation ensures adequate oxygen supply and air exchange throughout your session. Air stays breathable even at peak heat.
Mineral wool insulation
2.1" thick mineral wool insulation between every wall, paired with rubber seals and tempered glass, locks heat in for consistent thermal performance.
Freestanding or alcove
Designed to install either freestanding in a room or built into an alcove. The C1 fits where you want it, with a 2" minimum wall clearance.
About Kohler
Heritage you can trust
150+ years of bathroom and wellness craftsmanship
Founded in 1873, Kohler is one of the most recognized names in bathrooms, wellness, and home design worldwide. The C1 sauna brings that heritage of premium materials, refined engineering, and meticulous finish into the sauna category combining traditional Finnish-style heat with the contemporary build quality Kohler is known for.
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Graphite Grey exterior — modern, architectural, contemporary
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Premium Scandinavian spruce interior — tongue-and-groove, warm character
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FERO electric heater — sauna stones, heater guard, traditional steam
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Tempered glass detailing — 0.3" door and windows, beech wood handle
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Smart controls — external digital panel, dual thermostatic control
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5-year limited warranty — backed by Kohler directly
About Kohler
Built for the home, engineered for performance
Kohler designs every product with the same philosophy: premium materials, considered engineering, and finishes that last. The C1 sauna is no exception it's a wellness fixture built to spa-grade standards but designed for the realities of residential installation, daily use, and long ownership.
From the freestanding-or-alcove flexibility to the multiple size and floor options, the C1 represents what happens when a brand with deep heritage takes the sauna category seriously: a product that's adaptable, beautiful, and built to outlast trends.
Manuals & Documents
Everything you need before and after installation
Download the official Kohler C1 manuals, spec sheets, and warranty documentation below. The Installation and Operation Manual is the most important review it before your delivery arrives so you know what to expect on installation day. A licensed electrician is required for the heater installation.
Installation & Operation Manuals
Spec Sheets — No Floor
Spec Sheets — Full Floor
Additional Documents
Warranty
Kohler 5-year Limited Warranty
Every Kohler C1 sauna is backed by Kohler's 5-year limited warranty for residential use, covering defects in materials and workmanship from the date of purchase as long as the original purchaser owns the product. Kohler accessories included with the sauna are covered for 1 year under the same terms. Kohler will, at its election, repair or replace defective product covered by the warranty when inspection discloses defects occurring under normal usage. Damage caused by accident, misuse, abuse, improper installation, or commercial use is not covered. Proof of purchase from an authorized dealer is required for any claim and we are an authorized Kohler dealer.