FD-4 Trinity Infra-Steam Sauna

The only 2-person hybrid sauna engineered for full-spectrum infrared, authentic steam, and red light therapy — all on a 120V plug. The FD-4 combines medical-grade near-infrared, a Harvia Finnish steam stove, and antimicrobial cedar in a compact, easy-to-install design.

Features

• Heats to 170°F (infrared) or 190°F (steam) – dual heat flexibility

• Dual infrared system: Carbon 360° far-IR + UL-listed Spectrum Plus™ near-IR

• Harvia Vega Compact 1.9 kW traditional heater with steam stones (included)

• Built-in 650nm red light therapy – supports skin, circulation, recovery

• Digital touchscreen control with WiFi remote app access

• Bluetooth audio with premium 6" built-in speakers

• Constructed from antimicrobial Western Red Cedar (interior) and rot-proof Thermal Plus™ Aspen (exterior)

• ETL safety certified with ultra-low EMF heaters

• Assembles in under 60 minutes – no special tools or installers required

Specifications

Construction & Materials

The FD-4 features a double-walled cabin lined with Grade-A Western Red Cedar — naturally antimicrobial and aromatic — and a Thermal Plus™ Aspen exterior that will never rot, warp, or decay. The walls are insulated for maximum heat retention and energy efficiency. Its 8mm tempered glass door provides durability and a clean aesthetic.

Installation

The FD-4 is designed for indoor use only and fits under standard 8-ft ceilings. It assembles in 30–60 minutes with two people. No tools or professional installation required — the panels lock together via pre-fitted hardware, and the wiring is plug-and-play. It sits on any flat indoor surface including tile, wood, or carpet. Adjustable leveling feet are included.

Operation & Usage

Once plugged into a standard 120V / 15A outlet, use the touchscreen or app to power on the infrared system (up to 170°F), set your session time (up to 60 minutes), and control lighting and audio. Activate the Harvia stove separately via built-in controls to reach up to 190°F. Add water to the included sauna stones for true Finnish-style steam. Use infrared, steam, or both. No plumbing required.

EMF & Safety

• The FD-4 is built with safety at its core:

• Ultra-low EMF output, third-party tested

• ETL certified to UL/CSA electrical safety standards

• Built-in overheat protection and session timer

Zero off-gassing materials or adhesives
Ideal for daily use in residential settings.