Finnleo Designer B 6.0 kW (240V 1PH) Sauna Heater

Finnleo Designer-B 6.0 kW (240V, 1PH) Sauna Heater

The Finnleo Designer-B 6.0 kW electric sauna heater delivers the same deep, even, authentic Finnish heat found throughout the Finnleo lineup, with one key difference: all controls are built directly into the front of the heater. There is no separate wall-mounted control, no external contactor box, and no additional low-voltage wiring to run — the thermostat and timer live right on the heater itself, making the Designer-B an ideal choice for installations where a remote control panel isn't wanted, isn't practical, or needs to be avoided for simplicity and lower installed cost.

Construction & Design

The Designer-B is a wall-mounted, stainless-steel sauna heater built for durability in the high-heat, high-humidity sauna environment. The heating chamber houses three 2,000W tubular heating elements (240V) arranged so that rocks surround and sit directly above and between the elements, allowing heat to radiate evenly through the stone mass rather than directly off bare elements. A rock grate and wall-mounting bracket are supplied to properly position the heater and maintain correct clearance from the back wall. The heater ships complete with sauna rocks included.

Integrated Controls

Unlike SaunaLogic2-controlled Finnleo heaters, the Designer-B's thermostat and timer are mounted directly on the heater's front control panel. The thermostat knob adjusts bath temperature by turning clockwise to raise heat and counter-clockwise to lower it. The built-in timer uses a "9 plus 1" design: turning the dial into the 1-hour operating zone starts the heater immediately, while turning it into the 1–9 zone delays heater start-up by up to nine hours — letting the sauna warm up and be ready exactly when needed, with no smart app or additional wiring required. A built-in high-limit control automatically shuts the heater down if the sauna room temperature rises to an abnormal level; the reset button is located on the bottom of the heater.

Room Size & Heating Capacity

The Designer-B 6.0 kW is engineered for sauna rooms from approximately 175 to 425 cubic feet (minimum floor area of roughly 21 sq. ft.), with a minimum wall height of 74" and maximum wall height of 96". This makes the 6.0 kW output well suited to mid-sized home and light commercial saunas that fall between the smaller 4.5 kW and larger 8.0 kW Designer-B models.

Electrical Specifications

The 6.0 kW Designer-B is available in single-phase or three-phase configurations. For 240V single-phase operation, the heater draws 25 amps and requires 10-2 W/G copper supply wire rated for a minimum of 90°C; on 208V single-phase, draw is 28.8 amps requiring 8-2 W/G wire. Three-phase 240V configurations draw 14.4 amps on 12-3 W/G wire, while 208V three-phase draws 16.7 amps on 12-3 W/G wire. All wiring must be installed by a licensed electrician in accordance with the National Electrical Code and local regulations, and the heater must be properly grounded. No electrical outlets or receptacles may be installed inside the sauna room.

Safety & Installation Requirements

• A wooden heater guard rail is required to prevent bathers from accidentally contacting the heater, installed per the clearances specified in Finnleo's installation diagrams
• Minimum clearance from the heater to wooden surfaces (benches, walls, fencing) is 2 inches; mounting brackets are supplied to maintain proper wall clearance
• Minimum ceiling clearance above the heater is 44"; benches must not be located directly over the heater
• Two metal safety placards are included: a CAUTION placard mounted on the interior wall directly above the heater, and a WARNING placard mounted on the exterior of the sauna door at eye level
• Sauna doors must open outward and must never have a permanent locking or latch mechanism — only magnetic catches, friction catches, or spring/gravity closures are acceptable
• No shower and no electrical receptacle may be installed inside the sauna room
• Recommended minimum wall insulation of R-12 in 16" on-center 2x4 stud construction, with recommended minimum flooring thickness of 5/8"
• The heater must never be operated without the rock compartment properly filled and the rock guard in place
• Only a contactor rated for a minimum of 250,000 duty cycles may be used

Ventilation

Proper sauna ventilation should exchange the room's air approximately 6 times per hour. A fresh-air inlet vent should be located in the sauna wall directly below the heater, with the air outlet positioned lower than the upper benches, as far from the heater as possible, and roughly two feet higher than the inlet vent. Vent sizing should follow UL Specification 875: for room floor areas under 31 sq. ft., the minimum vent opening is 9.3 sq. in.; for areas of 31 sq. ft. or more, minimum vent size equals 0.3 times the floor area in square feet.

Rock Loading

Sauna rocks are included and must be loaded correctly for proper heater performance and longevity: smaller rocks go in first around the outer perimeter of the heating chamber, all four sections (front, the two center sections between elements, and back) must be completely filled, outer sections should use smaller rocks packed more tightly, the center sections should have rocks placed loosely to preserve airflow, and all elements must be fully covered with rocks loosely stacked 2–3 inches above the tops of the elements. Rocks should be inspected and any pieces smaller than 2" discarded and replaced annually.

Using the Sauna

A typical sauna session involves entering for 10–15 minutes or until perspiration begins, followed by a cool shower and 10–15 minutes of rest, repeated 2–3 times and finished with a brisk cool rinse. Bathers may splash approximately half a cup of water onto the heated rocks at a time to create steam, taking care to stay clear of the rising steam. Smoking, exercising, and drinking alcohol inside the sauna room are not recommended, and chlorinated pool or spa water should never be poured on the heater, as it can cause corrosion damage.

What's Included

• Finnleo Designer-B 6.0 kW sauna heater with integrated front-panel thermostat and 9+1 hour delay timer
• Three 2,000W heating elements (240V)
• Sauna rocks
• Rock grate and wall-mounting bracket
• CAUTION and WARNING metal safety placards
• Built-in high-limit safety control with reset button
• Installation and Operating Instructions manual

Maintenance

The sauna room should be aired out after each use by leaving the door and vents open, and washed down at least weekly with warm water and soap or detergent for rooms in daily use. The heater exterior should be wiped down periodically with a damp cloth to remove lint and dust, and rocks should be removed, cleaned, and replaced as needed once a year. Benches and supporting structures should be inspected annually for dry rot or deterioration and replaced immediately if signs of damage are found.

Why Buy Finnleo From Us

Finnleo, built by Sauna360 in Cokato, Minnesota, is one of the most trusted names in authentic Finnish sauna. Every heater is safety-tested and listed for North America. We are an authorized dealer offering full factory warranty, expert sizing help, and support before and after your purchase. Have a question about fit, voltage, or lead time? Reach out and a sauna specialist will help you spec it correctly the first time.