SaunaLife Model S4B — SOAK-Series Wood-Burning Hot Tub

Transform your outdoor space into a premium soaking retreat. The SaunaLife Model S4B blends efficiency, craftsmanship, and comfort into a luxury wood-fired hot tub built for up to six bathers.

Key Features & Highlights

• Thermo-Spruce Exterior
  The surround is made from thermally treated spruce, which offers greater durability and weather resistance—claimed to last up to twice as long as cedar. 

• Fully Assembled & No Electricity Required
  The tub arrives ready to use with zero assembly and requires no electrical connection—ideal for off-grid, eco-conscious setups. 

• Capacious Interior (304 Gallons+)
  With over 304 gallons of water capacity, the S4B comfortably accommodates six people, allowing full immersion and spacious seating. 

• Ergonomic Fiberglass Lining
  A thick, dark-grey contoured fiberglass interior molds to the body and offers a smooth, easy-to-clean surface. 

• High-Efficiency Stainless Steel Heater Design
  The wood-burning heater features a self-cleaning corrugated stove with a secondary chamber that captures exhaust heat, reducing wood consumption by up to 50%.
  Heat distribution is optimized via a water-channel system that moves cooler water through a lower chamber and redistributes it through an upper channel to equalize temperature. 

• Rapid Heat-Up Capability
  The S4B can heat from around 40 °F (5 °C) to 95 °F (35 °C) within 1.5 to 2 hours, making it one of the fastest-heating wood-fired tubs available. 

• Premium Exterior Details & Cover
  The exterior surround has a 1.65″ build, painted black, and includes matching spruce steps. An insulated, steel-reinforced foam cover (folding design) and marine-grade vinyl exterior protect the tub when not in use. 

• Built-In Drainage & Convenience Features
  A drainage tap is integrated for easy maintenance. The stove, chimney, and support hardware are built with polished 304 stainless steel to resist corrosion. 

• Dimensions & Capacity

  • Exterior: ~79" diameter × 37" height 

  • Interior: ~71" diameter × 33" depth

  • Water Capacity when filled: ~304 gallons 

  • Filled weight: ~3,064 lbs 

Benefits & Use Cases

• Group Soaking & Social Wellness
  Ideal for couples or family soak sessions—enjoy relaxation and connection in the same immersive environment.

• Efficient Fuel Use & Sustainability
  Its advanced heating system maximizes fuel efficiency, reducing wood usage and operating costs.

• Off-Grid Compatibility
  With no need for electricity, the S4B fits remote cabins, backyard retreats, or environments without standard power access.

• Fast-Start Enjoyment
  The rapid heating capability gets you into warm water in under two hours, perfect for spontaneous wellness routines.

• Low-Maintenance & Durable Design
  The fiberglass lining, stainless components, and treated wood shell balance aesthetic appeal with ease of care and long life.

Why the S4B Stands Out

Many hot tubs require electrical hookups, complex assembly, or modular parts. The Model S4B cuts through that complexity by delivering a fully assembled, electricity-free, high-efficiency soaking solution. Its combination of smart engineering, premium materials, and capacity for up to six bathers positions it as a standout choice for anyone who wants luxury, sustainability, and performance in one package.