SaunaLife Model S4B

Luxury Wood-Burning Hot Tub Experience

The SaunaLife SOAK-Series Model S4B combines Scandinavian craftsmanship, modern efficiency, and timeless relaxation in a beautifully designed wood-burning hot tub. Built for up to six people, it delivers the perfect setting to relax with family and friends while enjoying the luxury of outdoor bathing.

Ready to Use, Easy to Enjoy

Arriving fully assembled, the Model S4B is simple to set up and ready to use. Its ergonomically contoured fiberglass interior offers comfort and easy maintenance, while the thermally enhanced spruce exterior ensures superior durability and resistance to the elements.

Engineered for Efficiency & Performance

Precision-crafted in Northern Europe, the Model S4B heats water up to three times faster than traditional wood-fired hot tubs—no electricity required. Its self-cleaning corrugated stove features a secondary chamber that transfers heat from smoke, reducing wood consumption by up to 50%. Airflow between the fiberglass shell and wood exterior is super-heated to accelerate heating, while a smart circulation design ensures even water temperature throughout the tub.

Fastest Heating in Its Class

With its highly efficient wood stove, the S4B can heat 304 gallons of water from 40°F to 95°F in just 1.5 to 2 hours, making it the fastest-heating wood-burning hot tub available.

A Backyard Oasis of Wellness

Blending efficiency, durability, and luxury, the SaunaLife Model S4B transforms your backyard into a private retreat for relaxation, recovery, and connection.

Includes

Model S4B Outdoor Wood-Burning Hot Tub  

• Fully assembled hot tub 
• Steps 
• Insulated cover  
• Drainage with tap 
• Polished stainless steel chimney 
• Chimney cap 

Model S4B Outdoor Wood-Burning Hot Tub   

• Thermo-Spruce materials (lasts up to 2X longer than Cedar)  
• Luxury outdoor wood-burning hot tub 
• Designed for outdoor ergonomic hot tub bathing experiences 
• Arrives fully assembled and no electricity required (eco-friendly) 
• Spacious interior holds over 304 gallons of pure water bathing pleasure 
• Thick dark grey contoured fiberglass lining provides enhanced bather comfort 
• Stainless steel wood-burning heater utilizes dual heat compartments for unmatched efficiency   
• Rapid response heat-up time prepares water to ideal temperatures in under 2-hours 
• Wood-burning heater constructed of 304 stainless steel 
• Polished stainless steel chimney with protection 
• Durable Thermo-Spruce tub surround (1.65” thick), painted black  
• Superior thermal resistance (R-value) to retain heat  
• Matching Thermo-Spruce wood steps for easy access 
• Extra thick steel reinforced foam cover, folds for ease of removal and storage 
• Dark grey marine grade vinyl cover exterior 
• Integrated hot tub drainage tap 
• Up to 6 bathers 
• Exterior dimensions – 79" diameter and 37” high  
• Interior dimensions – 71" diameter and 33” deep 
• Designed by SaunaLife and handcrafted in Northern Europe 

Thermo-Spruce Material Advantages 

• Lasts up to 2X longer than Cedar 
• Superior thermal resistance (R-value) 
• Eco-friendly 
• Ideal for water use (stable)  

Technical Specifications

• Model: S4B
• Material: Thermo-Spruce
• Interior Dimensions: 71" Diameter × 33" D
• Exterior Dimensions: 79" Diameter × 37" H
• Water Capacity: 304 gallons
• Product Weight (filled): 3,064 lbs
• Stove Dimensions: 19.8" L × 11.8" W × 13.1" H
• Chimney Dimensions: 95" H × 4.7" Diameter
• Maximum Wood Length: 16"
• Maximum Temperature: 106°F
• Shipping Dimensions: 91" L × 46" W × 87" H
• Shipping Weight: 595 lbs

Installation Manual

S4 Diagram

S4 Warranty