Simple installation, simple operation, reliable—the Designer B delivers authentic Finnish heat with the convenience of built-in controls.
The Finnleo Designer B is a professional-grade electric sauna heater with built-in controls—no external control boxes, no complicated wiring, just a compact stainless steel unit that mounts on your wall and delivers perfect heat every time.
Available in three sizes to match any residential sauna, it proves that the best sauna experiences come from heaters that just work—day after day, year after year, with controls so intuitive that your only decision is how hot you want it.
When you’re looking for a quality heater no a budget, this is the one to go with.
When it comes to creating the perfect sauna environment, your heater choice determines everything—from the quality of löyly to the longevity of your investment. The Designer B combines decades of Finnish innovation with practical features that make every sauna session exceptional:
Less waiting, more relaxing. Properly sized for your space, the Designer B reaches optimal temperature quickly, using less energy than oversized heaters while delivering consistent, enveloping heat.
No external control box needed, saving installation costs and complexity. The integrated timer and thermostat mean fewer wall penetrations, cleaner installation, and everything you need right at your fingertips—perfect for retrofit projects or rooms where running control wiring would be challenging.
Program your sauna to be ready exactly when you want it. Set it before work and come home to a perfectly heated sauna, or delay the start time up to 9 hours for ultimate flexibility in your daily wellness routine.
Whether your sauna is small, medium, or large—there’s a perfect SL2 model for you. Available in 4.5kW, 6.0kW and 8.0kW (see cu ft requirements below).
Meet all building codes with confidence. Fully approved for permanent installation with splash-proof construction, high-limit safety controls, and proper clearances marked directly on the unit for inspector-friendly installation.
There are three models of the Designer B Knob-Control Sauna Heater, the 4.5kW, the 6.0kW and the 8.0kW.
The Designer B’s control knobs are conveniently located on the front face of the heater, positioned below the heating chamber for easy reach.
Two simple dials control everything: the left knob sets your temperature via the thermostat, while the right knob operates the 9+1 hour timer. The controls can also be relocated to either side of the heater during installation if your layout requires it—perfect for corner installations or unique room configurations.
If you are looking for a Wi-Fi sauna heater the Designer SL2 is another popular option.
Turn the timer clockwise past “1” then back to “ON” for immediate heating, or set anywhere from 1-9 for delayed start. The thermostat offers precise temperature control with clear markings that make finding your perfect heat effortless.
The high-limit control with manual reset button ensures safe operation, automatically shutting off if temperatures exceed safe levels—though proper installation and rock maintenance/ placement make this extremely rare.
We’re not just sauna dealers—we’re sauna users, builders, and enthusiasts with Finnish roots and Minnesota values.
With 45+ five-star Google reviews and a showroom where you can experience authentic Finnish sauna firsthand, we’re proud to be one of Minnesota’s most trusted sauna builders—transforming homes one beautiful sauna at a time.
The Designer B has earned its reputation through decades of reliable performance in thousands of saunas. Simple enough for DIY installation, robust enough for daily commercial use, and backed by both Finnleo’s engineering excellence and our local expertise—it’s the smart choice for authentic sauna heat.
Ready to add the perfect heater to your sauna project? Tell us about your space and we’ll ensure you get the right Designer B model with everything needed for a perfect installation.
If you’re comfortable with basic tools and can follow instructions, installation is straightforward—mount the bracket, hang the heater, connect the wiring. However, electrical connections must be done by a licensed electrician per code. Many customers do all the prep work themselves and just have an electrician make the final connections, saving significant money.
Yes, the Designer B requires 240V electrical service, just like an electric dryer or oven—this is standard for all electric sauna heaters. Your electrician will run a dedicated circuit from your electrical panel with the appropriate wire gauge based on your model. Most homes built after 1960 already have 240V service available. The heater can also operate on 208V (common in condos) with slightly reduced output. Three-phase power is available for commercial installations
Proper sizing is crucial for performance and efficiency. Measure your sauna’s length x width x height to get cubic feet, then match to our specifications. When in doubt, we recommend the larger size within range—it’s better to have a heater that reaches temperature quickly and cycles off than one that runs constantly. We’ll help calculate the perfect size when you give us a call at 612.505.9700.
It includes a strong warranty 5-year warranty from Finnleo. Tech support is based in Cokato, MN.
The Designer B requires the same ventilation as any sauna heater—fresh air inlet below the heater and exhaust outlet on the opposite wall. The manual includes the exact formula for calculating vent sizes based on your room size. Proper ventilation ensures comfort, prevents the high-limit from tripping, and extends heater life.
If you have other questions or need specific information, don’t hesitate to ask. We have years of sauna experience and will help you with what you need.
Let’s Build Your Dream Sauna.
500 Cokato St W Suite #4,
Cokato, Minnesota 55321
Monday – Friday: 8AM-5PM
After hours appointments available, please call 612.505.9700 to schedule.
Our response times are quick. A team member will reach out to you after you submit the form!
After you submit a form, a team member will reach out to you about your custom indoor sauna project!
