SaunaLife
Wood-Fired Hot Tub 6 Person Outdoor Spa – SaunaLife Model S4 Thermo-Spruce Luxury Soaking Tub
Model S4 Outdoor Wood-Burning Hot Tub
The SaunaLife SOAK-Series Model S4 represents a premium standard in wood-burning hot tub design, combining exceptional craftsmanship, efficiency, and luxury. It delivers a refined outdoor bathing experience built for relaxation, social gatherings, and long-term wellness use.
Ready for Your Hot Tub Experience
The Model S4 wood-fired hot tub arrives completely assembled and is simple to set up. Its ergonomically shaped fiberglass interior comfortably accommodates up to 6 people, making it ideal for family use or hot tub gatherings. The interior surface is designed for easy cleaning, while the exterior is crafted from thermally enhanced spruce to provide superior weather resistance and long-lasting durability.
Engineered for Efficiency and Performance
Designed and handcrafted in Northern Europe, the Model S4 is engineered for maximum heating efficiency. It reaches optimal bathing temperature in approximately 1/3 of the time of traditional wood-fired hot tubs and requires no electrical connection, making it fully off-grid and eco-friendly.
At the core of the system is a self-cleaning corrugated stainless steel stove featuring dual heat compartments that transfer heat from smoke and reduce wood consumption by up to 50% compared to conventional designs. The system also superheats the air between the fiberglass lining and the wooden exterior to accelerate warming. A carefully engineered circulation system draws cooler water through a lower channel and redistributes it through an upper channel to maintain balanced water temperature throughout the tub.
With this design, the Model S4 can heat 304 gallons of water from 40°F (5°C) to 95°F (35°C) in approximately 1.5 to 2 hours, making it one of the fastest-heating wood-burning hot tubs available.
Built for Comfort and Long-Term Use
The interior features a thick dark grey contoured fiberglass lining that enhances comfort for up to 6 bathers. The exterior is constructed from Thermo-Spruce (lasting up to 2X longer than cedar), providing excellent thermal resistance and structural stability. The 1.65” thick tub surround is finished in black for a modern and durable outdoor appearance.
Matching Thermo-Spruce steps provide safe and easy entry, while the insulated cover helps retain heat efficiently. A polished stainless steel chimney with protective cap ensures safe and reliable operation during use.
Thermo-Spruce Material Advantages
Lasts up to 2X longer than Cedar
Superior thermal resistance (R-value)
Eco-friendly and stable for water use
Ideal for long-term outdoor performance
Specifications
Weight: 595 lbs
Width / Depth: 79" diameter
Height: 37"
Capacity: up to 6 bathers
Water capacity: 304 gallons
Heating time: approximately 1.5–2 hours (from 40°F to 95°F)
Included Components
Fully assembled hot tub
Thermo-Spruce tub surround (painted black, 1.65” thick)
Ergonomic fiberglass interior
Matching Thermo-Spruce steps
Insulated folding cover with marine-grade vinyl exterior
Integrated drainage tap
Stainless steel wood-burning heater
Polished stainless steel chimney with cap
The SaunaLife Model S4 delivers a complete outdoor wellness solution, combining rapid heating performance, durable construction, and premium comfort for an elevated wood-fired hot tub experience.
Resources
Learn how Infinity Saunas ships your sauna safely to your door. Find details on delivery times, freight shipping, and what to expect when your order
Every Saunalife sauna is protected by a Lifetime Warranty covering the cabin structure and non-electrical components.
Heater warranties are provided directly by the manufacturer and vary by brand:
Harvia: 2 years residential warranty
HUUM: Limited 3-year residential warranty (excluding heating elements)
Saunum: 2 years residential warranty
Model S4 Outdoor Wood-Burning Hot Tub
The SaunaLife SOAK-Series Model S4 represents a premium standard in wood-burning hot tub design, combining exceptional craftsmanship, efficiency, and luxury. It delivers a refined outdoor bathing experience built for relaxation, social gatherings, and long-term wellness use.
Ready for Your Hot Tub Experience
The Model S4 wood-fired hot tub arrives completely assembled and is simple to set up. Its ergonomically shaped fiberglass interior comfortably accommodates up to 6 people, making it ideal for family use or hot tub gatherings. The interior surface is designed for easy cleaning, while the exterior is crafted from thermally enhanced spruce to provide superior weather resistance and long-lasting durability.
Engineered for Efficiency and Performance
Designed and handcrafted in Northern Europe, the Model S4 is engineered for maximum heating efficiency. It reaches optimal bathing temperature in approximately 1/3 of the time of traditional wood-fired hot tubs and requires no electrical connection, making it fully off-grid and eco-friendly.
At the core of the system is a self-cleaning corrugated stainless steel stove featuring dual heat compartments that transfer heat from smoke and reduce wood consumption by up to 50% compared to conventional designs. The system also superheats the air between the fiberglass lining and the wooden exterior to accelerate warming. A carefully engineered circulation system draws cooler water through a lower channel and redistributes it through an upper channel to maintain balanced water temperature throughout the tub.
With this design, the Model S4 can heat 304 gallons of water from 40°F (5°C) to 95°F (35°C) in approximately 1.5 to 2 hours, making it one of the fastest-heating wood-burning hot tubs available.
Built for Comfort and Long-Term Use
The interior features a thick dark grey contoured fiberglass lining that enhances comfort for up to 6 bathers. The exterior is constructed from Thermo-Spruce (lasting up to 2X longer than cedar), providing excellent thermal resistance and structural stability. The 1.65” thick tub surround is finished in black for a modern and durable outdoor appearance.
Matching Thermo-Spruce steps provide safe and easy entry, while the insulated cover helps retain heat efficiently. A polished stainless steel chimney with protective cap ensures safe and reliable operation during use.
Thermo-Spruce Material Advantages
Lasts up to 2X longer than Cedar
Superior thermal resistance (R-value)
Eco-friendly and stable for water use
Ideal for long-term outdoor performance
Specifications
Weight: 595 lbs
Width / Depth: 79" diameter
Height: 37"
Capacity: up to 6 bathers
Water capacity: 304 gallons
Heating time: approximately 1.5–2 hours (from 40°F to 95°F)
Included Components
Fully assembled hot tub
Thermo-Spruce tub surround (painted black, 1.65” thick)
Ergonomic fiberglass interior
Matching Thermo-Spruce steps
Insulated folding cover with marine-grade vinyl exterior
Integrated drainage tap
Stainless steel wood-burning heater
Polished stainless steel chimney with cap
The SaunaLife Model S4 delivers a complete outdoor wellness solution, combining rapid heating performance, durable construction, and premium comfort for an elevated wood-fired hot tub experience.
Resources
Learn how Infinity Saunas ships your sauna safely to your door. Find details on delivery times, freight shipping, and what to expect when your order
Every Saunalife sauna is protected by a Lifetime Warranty covering the cabin structure and non-electrical components.
Heater warranties are provided directly by the manufacturer and vary by brand:
Harvia: 2 years residential warranty
HUUM: Limited 3-year residential warranty (excluding heating elements)
Saunum: 2 years residential warranty
FAQ
Shipping
Orders are usually processed within 1 business day and delivered within 3–5 business days, depending on your location and the shipping carrier schedule. Large sauna units are shipped via freight delivery.
Your sauna will be delivered via curbside freight delivery. This means the carrier will deliver it to the nearest accessible point outside your home or building (such as your driveway or curb).
Other
Yes. Once your order ships, you will receive full tracking details so you can follow your delivery step by step.
Yes. All saunas include a manufacturer’s warranty that covers defects in materials and workmanship for a specific period, depending on the model.
Due to the size, handling, and special shipping requirements of sauna units, all sales are considered final. However, if your product arrives damaged or defective, we will arrange a replacement or resolution at no extra cost.
Orders can be canceled within 24 hours of purchase, as long as they have not yet been processed or shipped.
We accept all major credit cards and secure online payment methods to ensure a safe and smooth checkout experience.
Yes. Our support team is available to assist you after your purchase with setup guidance, delivery questions, and product support to ensure a smooth experience.
