Description

Finnmark Designs FD-4 Trinity 2-Person Hybrid Indoor Sauna with Traditional Heater, Infrared & Red Light Therapy | FD-KN004 - The Ultimate Combination Sauna

The Ultimate 3-in-1 Wellness Sanctuary

Three powerful therapies. One extraordinary sauna. The Finnmark FD-4 Trinity combines best-in-class wellness technologies into a single, beautifully crafted cabin: the deep heat of Full-Spectrum Infrared, the authentic steam of a Finnish Harvia™ stove, and the rejuvenating power of medical-grade Spectrum Red Light™ Therapy.

Designed for true versatility, the FD-4 lets you enjoy each system on its own or combine them seamlessly for a fully personalized session. UL-listed Spectrum Plus™ infrared heaters deliver muscle-penetrating warmth up to 25x more effective than standard carbon panels. For those who prefer tradition, the Harvia™ Vega Compact 1900 produces intense heat and rich steam up to 190°F. Complement your session with the Spectrum Red Light™ panel, clinically designed to stimulate collagen and restore skin vitality.

Every detail is designed for uncompromising luxury and performance. Crafted from antimicrobial Western Red Cedar and durable Thermal-Plus™ Aspen, the FD-4 is built for a lifetime of wellness. With intuitive Wi-Fi controls, premium Bluetooth audio, and a spacious two-tier bench system, your perfect sauna experience is always just a touch away.

The FD-4 Trinity isn’t just a sauna—it’s your complete daily retreat for recovery, relaxation, and rejuvenation.

Features

• 3-in-1 Sauna
  • Traditional Finnish Steam: Genuine Harvia™ Vega Compact 1900 heater with stones for high heat and steam (up to 190°F).
  • Full-Spectrum Infrared: UL-listed Spectrum Plus™ infrared heaters for deep, penetrating warmth—up to 25x more effective than carbon heaters (Wi-Fi controllable via app).
  • Medical-Grade Red Light Therapy: 192-diode Spectrum Red Light™ panel producing 650nm therapeutic light to support collagen and skin health.
  • Traditional heater, infrared heaters, and red light therapy can be used together or separately for customizable sessions

• Smart Comfort & Control
  • Wi-Fi App Control: Preheat your sauna's infrared heaters and manage settings from anywhere via the Smart Life™ app.
  • Built-in Touchscreen Controller: An intuitive LCD command center for full control over temperature, session timing, lighting, and more.
  • Premium Hi-Fi Sound: Stream your favorite music or podcasts via Bluetooth to two 6" marine-grade speakers for rich, immersive sound.
  • Active Ventilation: A ceiling exhaust vent and fresh air intake keep air circulating and comfortable—no additional external venting required.

• Premium Craftsmanship
  • Interior: Antimicrobial Western Red Cedar, naturally resistant to mold and bacteria.
  • Exterior: Thermal-Plus™ Aspen, engineered to prevent warping, rot, and decay.
  • Door & Glass: Heavy-duty 8mm tempered glass door maximizes durability and heat retention.
  • Seating: Extra large two-tier benches let you choose between high-heat intensity or gentler relaxation.

• Safety & Assurance
  • Ultra-Low EMF: Certified for safety by a NASA award-winning facility.
  • Simple Assembly: Panels assemble in about 1 hour with two people and minimal tools. The system is pre-wired for easy connection, with the final hookup of the Harvia™ heater requiring a licensed electrician for hardwiring.
    
  • Comprehensive Warranty: 10-year limited craftsmanship warranty and 2-year Harvia™ heater warranty.

Specifications

Specifications:

PERFORMANCE

• Seats: 2 People
• Maximum Temperature: 190°F (Traditional), 170°F (Infrared)
• Warm-up Time: Approx. 50-60 minutes to reach maximum temperature
• IR Emissivity: .997

HEATING SYSTEM

• Type: True Hybrid System with 7 heating elements
• Infrared Heaters: 8 Spectrum Plus™ dual-wave (far and mid) infrared heaters with the following placement:
  • Three (3) on the back wall
  • One (1) under the bench
  • Two (2) on each side wall
• Traditional Heater: 1 Harvia Vega Compact Pro 1.9kW heater (mounted on front interior wall)
• Infrared Power: 1750 Watts

ELECTRICAL REQUIREMENTS

• Infrared System/Controls: Requires a standard, dedicated 120V / 15A household outlet. (Unit has a NEMA 5-15P Plug, 3 prong)
• Traditional Heater: Requires a dedicated hardwired circuit installed by a licensed electrician with one of the following options: Standard: 120V / 20A circuit, or Optional: 240V / 15A circuit
• Power Cord Length: Approx. 9 feet

DIMENSIONS & PLANNING

• Exterior Dimensions: 48" W x 48" D x 83" H
• Interior Dimensions: 44.25" W x 45.5" D x 75.5" H
• Bench Dimensions: Top Bench 44.5" x 19", Lower Bench 44.5" x 15"
• Room Volume: 86 cu. ft.
• Door Dimensions: 23.625"W x 68.875"H
• Glass Thickness: 8mm w/Gasket
• Required Clearance: A minimum of 3 inches of space on all sides and the top is required
• Connection Locations: Wiring for the traditional heater routes through the floor on the front-left side. The main power cord for the cabin exits through the roof panel.

MATERIALS & WEIGHT

• External Materials: European Thermo-Aspen
• Interior Materials: Clear “A” grade Western Canadian Red Cedar
• Product Weight: 437 lbs
• Shipping Weight: 618 lbs (including pallet)
• Shipping Dimensions: 80"W x 40"D x 58"H

Harvia Vega Compact 1900 (Included)

• Wall-mounted install
• Stainless Steel construction
• 1.9kW
  
• Built-in controls (the operating switches can be installed on the right or left side of the heater)
• Stones capacity 29lbs of sauna stones (1 Box-AC3000) (Included)
• Designed, engineered, and made in Finland
• Dimensions: 11"W (279mm) x 11"D (279mm) x 21" (533mm)
• 2-Year Warranty (Consumer use)

Includes

Includes:

Sauna Cabin & Structure

• Complete set of Thermal Plus™ Aspen (exterior) & Western Canadian Red Cedar (interior) wall, floor, and ceiling panels
• 8mm-Tempered Glass Door with handle, for the ultimate thermal retention
• Two-Tier Bench System
• Removable and adjustable sauna feet for uneven surfaces
• Built-in Fresh Air Intake & Exhaust Vents

Heating & Therapy Systems

1. Traditional Heat System
   • Harvia Vega Compact 1900 Traditional Heater
   • 1 Box of genuine Harvia Sauna Stones (approx. 29 lbs)
     
2. Infrared Heat System
   • A total of 8 Spectrum Plus™ Dual-Wave Infrared Heaters with the following placement for full-body coverage:
     • Three (3) heaters on the back wall
     • Two (2) heaters on each side wall, for a total of four (4)
     • "One (1) heater under the bench
       
3. Red Light Therapy System
   • One (1) Medical-Grade Red Light Therapy Panel with Chromotherapy

Electronics & Controls

• V2 5" LCD Touchscreen Controller with Wi-Fi control and Bluetooth for audio
• Power Supply Unit & All Necessary Cables
• Interior Heater Connections with Protective Wood Cover
  

Certifications & Warranty

• ETL Certification
• 10 Year Limited Warranty

Assembly & Installation

Assembly & Installation:

DIY Cabin Assembly

The sauna cabin is designed for easy, intuitive assembly. With two people, it can typically be put together in about an hour. We recommend watching the official step-by-step video guide below.

Professional Heater Connection

For your safety and to comply with the product warranty, the final connection of the traditional Harvia heater must be performed by a licensed electrician. This is a straightforward task for a professional, and you can provide them with the detailed manuals below.

Manuals & Documents

Finnmark Designs Hybrid Sauna Assembly Instructions and Owner's Manual

Harvia Vega Traditional Heater Installation and Operation Manual

Find a Local Electrician or Assembler

• Assembling the Cabin: An assembler may not be necessary. The sauna cabin itself is designed for a straightforward, two-person assembly that typically takes about an hour. Many of our customers enjoy doing this part themselves.

• Connecting the Heater: The need for a professional is not for building the cabin, but for the final heater connection. The official manufacturer's manual requires that the traditional Harvia heater be hardwired by a licensed electrician to ensure safety and keep your warranty valid.

While we do not offer installation services directly, these popular resources can help you find a qualified and licensed professional in your area:

• Yelp

• Angi(formerly Angie's List)

• Thumbtack

• Bathing Pro (for assemblers only)

Operating Instructions

Operating Instructions: Helpful tips for enjoying your sauna sessions

Your Trinity™ is equipped with Spectrum Plus™ infrared heaters. Infrared heat waves reach the body directly without having to heat the air inside the sauna.

Spectrum Plus™ infrared heaters are UL listed to ensure your safety using our sauna is top priority. These heaters will not degrade or fail prematurely like carbon heaters when introduced to a traditional heater's steam. Spectrum Plus™ infrared heaters were specifically manufactured for this purpose.

1) Preparing for your infrared session

• Review all health and safety instructions. If in doubt as to the advisability of using your infrared sauna, consult with your physician.
  
  
• The interior of the Finnmark Designs Infrared Sauna is made of the finest Western Canadian Red Cedar. It is aromatic and adds to the enjoyment of your sauna session. If the fragrance of the fresh wood is too strong during the first few months of use, first wipe the wood with a damp cloth to minimize the aroma.
  
  
• Always drink plenty of water before, during and after a session. Doing so will replenish fluids lost during perspiration.
  
  
• Do not eat anything at least an hour before your sauna session. It is better to go in the sauna on an empty stomach. You are more likely to feel uncomfortable sitting in a sauna with a full stomach.
  
  
• Choosing to take a hot shower or bath prior to the sauna session will further promote perspiration. However, dry off thoroughly before going into the sauna because excessive water will leave stains and might warp the wood.
  
  
• Provide at least 2-3 towels. One towel folded over several times for added cushioning on the bench. Another towel on the floor to absorb extra sweat. And a third towel to wipe off sweat.
  
  
• Start up your sauna and select the desired session temperature and time using the control panel.
  
  
• Allow approximately 15 to 20 minutes for the sauna to warm up to a comfortable temperature before beginning a session (warm up time is subject to the air temperature and is different for each model). Infrared Temperature (170°F) - Trinity™ 4x4 Time: 50-60 Min
  
  
• Please Note: Your sauna’s maximum temperature setting may not be achieved based on variations in ambient room temperature, air flow, placement of sauna, etc. If you are experiencing unusual warm-up times or if you have recently moved your sauna from one location to another, please call our technical support team for thermostat calibration help.

2) Setting session time and temperature

Your body will probably need a few weeks to fully adapt to regular use of your Finnmark Designs. Here are some average guidelines to set the time and temperature once you are used to the sessions:

• Time: Noticeable results are usually obtained with sessions of at least 30 minutes. For therapeutic use, sessions of 45 minutes are advised.
  
  
• Temperature: Many beginners need to start with a lower temperature and work their way up to a higher temperature. Some studies show therapeutic benefits at 163°. Finnmark Designs Saunas get to 170°. If perspiration does not start after 10 to 15 minutes, this usually indicates that the temperature is set too low to obtain good results.
  
  
• When using your Sauna for the first time:
  • Do not do more than three sessions a week during the first four weeks. You can do daily sessions after six weeks, if desired.
  • If you do not feel comfortable or relaxed during a session, lower the temperature and/or open the door of the cabin.

3) Useful information and tips for during your sauna session

• Make sure you have a towel on the floor and on the bench of the sauna to absorb perspiration.
  
  
• In order to maintain a clean and pleasant atmosphere inside your sauna, do not leave damp towels on the bench or floor. Remove them immediately after the session is over.
  
  
• Be sure to towel off excess sweat during your session to help the body perspire more freely.
  
  
• When the temperature reaches the level set on the control panel, the heaters will turn off and on periodically in order to maintain the desired temperature level inside of the sauna.
  
• The ceiling vent on the top panel can be opened at any time to introduce fresh air into the sauna.
  
  
• If you feel the need for more cooling, simply leave the door open until the air around you feels comfortable enough.
  
  
• Do not put any lotions or oils on the body or face prior to using the sauna. This may block the pores and hinder perspiration.
  
  
• Essential oils can help you to find more tranquility during your session.
  
  
• To make the most out of your sauna session, work your muscles while in the sauna. Stretch your arms, legs etc. to help relieve sore and tense muscles and massage the affected areas while in the sauna. If you wish to achieve a deep heating effect to a specific area, move it closer to a heater
  
  
• To relieve your ankles and feet more effectively, you must elevate them while inside the sauna.
  
  
• Shaving your face or legs with a razor while profusely sweating in a sauna yields an incredibly smooth result without the use of gels or foams.
  
  
• Do not forget to drink plenty of water before, during and after sessions to replenish lost fluids through perspiration.
  
  
• After the session is over, do not immediately jump into the shower. Since your body was heated up during the session, it will continue to sweat even after the heaters are off. Sit in the sauna with the door open and let your body cool off. Once you feel comfortable enough, take a warm (or cool) shower to rinse the perspiration off your body.