The SaunaLife Model S1 is a premium 1-person immersion tub crafted from durable Thermo-Pine wood, designed for cold plunge, ice bath, or hot soak therapy when paired with your own chiller or heater. Available in two finishes, S1N (Natural Thermo-Pine) and S1B (Black Thermo-Pine), you choose the look that fits your space, both versions ship with identical tub construction and the same warranty. The integrated drainage and chiller connection ports are built directly into the tub, ready to connect to any compatible external chiller or heater unit.
Premium Thermo-Pine, twice the lifespan of cedar
The S1 tub is crafted from durable Thermo-Pine wood with a 1.65" thick surround, a thermally treated Northern European softwood that lasts up to 2X longer than cedar. Choose between the warm natural Thermo-Pine finish (S1N) for a classic Scandinavian look, or the sophisticated black-stained finish (S1B) for a modern, architectural feel. Both versions deliver identical thermal performance and durability, the thick surround provides exceptional insulation that keeps the water at temperature longer between heating or chilling cycles.
Ergonomic fiberglass interior, 124 gallons
Inside, a thick contoured fiberglass insert contours to your body for genuine comfort during longer sessions. The Natural finish uses dark grey fiberglass, the Black finish uses matching black, both deliver the same enhanced bather comfort and durable construction. The 124-gallon capacity gives one bather full immersion without crowding, and the contoured shape means you're not awkwardly shifting position to find a comfortable spot. Built-in drainage and chiller connections come integrated into the tub.
Compatible with your choice of chiller or heater
The S1 tub ships with built-in chiller connection ports (3/4" NPT), so you can pair it with the chiller, heater, or combination unit of your choice. Use it as a dedicated cold plunge with an external chiller, as a hot soak tub with a water heater, or as a full contrast therapy system with a chiller/heater combination unit. The tub is designed to work with standard SaunaLife units (FDC-1A, AP-1) as well as compatible third-party equipment.
Pre-assembled and ready out of the box
The S1 ships fully assembled with matching Thermo-Pine stairs (matching the chosen finish, natural with the S1N, black with the S1B), so the only setup is positioning the tub, connecting your chiller or heater unit, and filling it. European craftsmanship from Northern Europe means every component is precision-built before it leaves the factory.
Premium 1-person immersion tub in your choice of finish (Natural S1N or Black S1B), built from durable Thermo-Pine that lasts up to 2X longer than cedar. 124-gallon ergonomic fiberglass interior, built-in chiller connection ports, matching Thermo-Pine stairs, and pre-assembled delivery, ready to pair with your chiller, heater, or combination unit.
1-person immersion tub Natural or Black finish Premium Thermo-Pine 124 gallon capacity Built-in chiller connections Pre-assembled Outdoor design Authorized SaunaLife dealer
Specifications
S1 tub dimensions & capacity
| Exterior dimensions |
41.3"H × 40" diameter |
| Interior dimensions |
34.4" diameter × 36" deep |
| Water capacity |
124 gallons |
| Capacity |
1 person |
| Product weight |
Approx. 200 lbs |
| Weight (filled) |
1,177 lbs (534 kg) |
Construction & materials
| Exterior |
Premium Thermo-Pine (1.65" thick) |
| Interior (S1N) |
Contoured fiberglass (dark grey) |
| Interior (S1B) |
Contoured fiberglass (black) |
| Stairs |
Matching Thermo-Pine, included |
| Drainage |
Built-in, 1" (3 cm) |
| Chiller connections |
3/4" NPT, built-in |
| Origin |
Handcrafted in Northern Europe |
| Wood lifespan |
Up to 2X longer than cedar |
Chiller / heater compatibility
| Connection ports |
3/4" NPT, built into tub |
| Compatible SaunaLife units |
FDC-1A chiller, AP-1 chiller/heater |
| Third-party units |
Any chiller / heater with compatible NPT fittings |
| Configuration |
Cold plunge, hot soak, or contrast therapy |
| Note |
Chiller / heater unit sold separately |
Available finishes
| Natural finish |
Model S1N (Thermo-Pine natural, dark grey interior) |
| Black finish |
Model S1B (Thermo-Pine black, black interior) |
| Construction |
Identical between both finishes |
Shipping & installation
| Configuration |
Fully pre-assembled |
| Shipping dimensions |
47.8"L × 46"W × 48.1"H |
| Shipping weight |
265 lbs (120 kg) |
| Installation type |
Outdoor |
| SKU / Model |
S1N (Natural) or S1B (Black) |

What's included
SaunaLife Model S1 immersion tub (pre-assembled)
Premium Thermo-Pine tub surround (1.65")
Contoured fiberglass interior (dark grey or black)
Matching Thermo-Pine stairs (Natural or Black)
Built-in drainage system (1")
Built-in chiller connection ports (3/4" NPT)
Foundation beams
Fiberglass insert
S1 tub installation manual
Warranty documentation
Why the SaunaLife S1 stands out
Choose your finish
Same premium tub, two distinct looks. S1N delivers warm natural Thermo-Pine with dark grey interior. S1B offers a black-stained finish with matching black interior.
Premium Thermo-Pine
Thermally treated Northern European pine that lasts up to 2X longer than cedar. The 1.65" thick surround provides exceptional insulation and durability outdoors.
Ergonomic fiberglass interior
Thick contoured fiberglass insert contours to your body for genuine comfort during long sessions. 124-gallon capacity gives full immersion without crowding.
Bring your own chiller
Built-in 3/4" NPT chiller connection ports let you pair the tub with the FDC-1A, AP-1, or any compatible third-party chiller, heater, or combination unit.
Pre-assembled delivery
The S1 arrives fully assembled with matching stairs. Position it, connect your chosen chiller or heater unit, fill with water, and you're ready to start.
Limited Lifetime warranty
SaunaLife backs the tub with a Limited Lifetime warranty on craftsmanship for residential use. Claims go directly through SaunaLife with full factory support.
About SaunaLife
European craft, American design
Designed in the U.S., crafted in Northern Europe
SaunaLife was founded by sauna enthusiasts who wanted to make premium-quality home wellness more accessible. Partnering with Nordic innovators, they leverage Scandinavian design, sustainable materials, and traditional construction techniques to deliver products that actually last. The S1 tub brings that same philosophy to cold plunge and immersion therapy.
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Two finish options, S1N (Natural) or S1B (Black)
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Premium Thermo-Pine, lasts up to 2X longer than cedar
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Built-in chiller connections, 3/4" NPT ports ready to pair
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Ergonomic fiberglass interior, contoured for real comfort
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Pre-assembled delivery, ready to use out of the box
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Limited Lifetime warranty, backed by the manufacturer
About SaunaLife
Live the SaunaLife
SaunaLife uses sustainably sourced, thermally treated Northern European wood across the entire product line, the same standard they apply to their Soak Series tubs that they apply to their flagship saunas. Every S1 tub is crafted to handle outdoor conditions for years with minimal maintenance.
The result is an immersion tub that fits naturally into a backyard, deck, or patio, looks intentional rather than industrial, and delivers the same therapeutic benefits as commercial-grade hydrotherapy in a tub designed for home ownership.
Manuals & Documents
Everything you need before and after installation
Download the official SaunaLife S1 tub installation manual below. Review it before delivery so you understand exactly how the tub installs and connects to your chosen chiller, heater, or combination unit. The S1 tub ships pre-assembled, ready to position and fill.
Installation Manuals
Warranty
Warranty
SaunaLife Limited Lifetime Warranty
Every SaunaLife Model S1 immersion tub (S1N or S1B) is backed by SaunaLife's Limited Lifetime Warranty on the tub's structural integrity and craftsmanship for residential use, the highest level of protection available in the category. Any chiller or heater unit paired with the tub is covered under its own manufacturer warranty terms. All warranty claims go directly through SaunaLife with full factory support. Proof of purchase from an authorized dealer is required to start any claim, and we are an authorized SaunaLife dealer. See the official warranty document above for full terms.