Finnmark FD-4 Trinity

The Finnmark FD-4 Trinity is the only home sauna in the world that combines three 
distinct modalities in a single room: full-spectrum infrared, traditional steam 
heat, and red light therapy — all powered by standard 120V outlets with no 
electrician required. If you have ever had to choose between infrared and 
traditional sauna bathing, the FD-4 makes that compromise unnecessary.

At the core of the Trinity is Finnmark's Spectrum Plus UL-listed short-wave 
infrared heater system — a distinction that matters. Short-wave infrared delivers 
deep-penetrating warmth that reaches muscles and joints more effectively than 
carbon panel heaters alone. The infrared system is independently verified as low 
EMF by a NASA award-winning testing facility, giving bathers the confidence of 
third-party validation. For full-body coverage, Spectrum Carbon 360 long-wave 
panels complement the short-wave heaters — the two spectrums working together 
deliver higher temperatures and a more complete infrared environment than any 
single-spectrum system.

For those sessions when you want the intensity of a traditional sauna, the included 
Harvia Vega Compact 1.9kW heater is wall-mounted inside the room and loaded with 
stones. Pour water across them and the room fills with genuine löyly — the moist, 
enveloping steam that is the hallmark of the traditional Nordic sauna experience. 
The combination of infrared and steam in the same session is something no other 
home sauna on the market delivers, and both run on standard 120V — no dedicated 
circuit required.

Completing the Trinity is the Spectrum Red Light panel — 192 LED diodes producing 
650nm red light at therapeutic intensity, adding a light therapy dimension to every 
session. The entire room is built from Western Canadian Red Cedar inside — naturally 
resistant to mold, bacteria, and fungus — and Thermal Plus Aspen outside, built to 
resist rot, warping, and decay. Controls are managed through a built-in LCD 
touchscreen Controller 2.0 with Bluetooth audio and 6" HiFi marine-grade speakers. 
ETL / Intertek certified.