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HUUM STEEL Mini 3.5 KW Series Sauna Heater

HUUM STEEL Mini 3.5 KW Series Sauna Heater

Regular price $1,130.00 USD
Regular price $1,230.00 USD Sale price $1,130.00 USD
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The compact STEEL Mini electric heater with extremely short safety distances is a wall-mounted model that is especially suitable for small steam rooms. Thanks to the well-optimized design the safety distances of STEEL Mini from the walls are only 5 cm. STEEL Mini is a narrower version of the STEEL heater.



  • Slender design
  • Suitable for use in small saunas with limited space
  • Small safety distances
  • Heats up to 25% faster due to internal air duct
  • For sauna rooms from 123 to 212 cu. ft.
  • Works with UKU controls (sold separately)
  • 133 pound stone capacity (required 4 boxes sold separately)
  • Direct contact between stones and heating elements
  • More exposed stones creates a longer and milder heat
  • Stainless steel construction
  • Stainless steel, industrial quality heating elements​
  • Wall-mount model
  • Designed, engineered, and made in Estonia
  • Dimensions: 12.6" W (320mm) x 6" D (150mm) x 38.4" H (975mm)
  • Limited 5-year warranty (excluding elements)


STEEL Mini 3.5 Specs:


STEEL Mini 3.5

  • Sauna room: 3,5-6 m³
  • Stone capacity: 60 kg
  • Watts: 3500
  • Volts: 240
  • Amps: 14.58
  • Fuse: 16 A
  • Phase: 1PH
  • Supply voltage 1-phase: 230 V 1N
  • Cable: 3 x 2,5 (N x mm²)


Safety Distance:


STEEL Mini 3.5

  • A - 50 mm
  • B - 420 mm


Package Contents:

  • 3.5kW sauna heater
  • Wall fastening bracket
  • Installation and operation manual
  • 5-Year limited warranty (excluding elements)


Respect for space

STEEL heater was developed with small home saunas and space saving in mind. Therefore it has a very slim design and significantly reduced safety distances from the walls. The small safety distances are achieved by optimizing the structure and placement of the internal air tunnel. However, the compactness does not come at the expense of efficiency. The internal air tunnel placed in the center of the heater provides effective airflow, speeds up the heating process by 25% and prolongs the lifespan of the heating elements.

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    Hand Crafted Saunas

    HUUM electric heaters and wood-fired stoves combines ancient saunabuilding knowledge with smart technology in acontemporary Nordic design inspired by nature. which delivers a superior heat and steam, as well as provide improved convenience and safety.

    Long days or rough days works. The HUUM sauna system will be waiting for you to relax at your home!

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    Frequently Asked Questions

    How to choose a sauna controller for an electric sauna heater?

    All three controllers share the same basic functions and design. The main difference between them is that UKU Local is made for only on-the-spot use while UKU Wi-Fi and UKU GSM can additionally be controlled through HUUM mobile app. LINK TO READ MORE!

    How can I replace my existing sauna heater with a HUUM heater?

    Does your current sauna heater work with a controller or is it a mechanical heater?

    If you have a sauna heater with a controller with a temperature control function, just replace the heater. Install the heater according to the product installation manual and with the help of a certified electrician.

    Do you have a mechanical sauna heater without a controller (the switch is on the heater)? In that case, you will need a controller with temperature control function and you will need to set up some cables. Follow the instructions from the product installation manuals and do it with the help of a certified electrician. You might need to open up some walls and install new cables.

    What size saunas are HUUM heaters suitable for?

    Among HUUM heaters you can find suitable models for both small and big sauna rooms with volumes ranging from 3-35 m³.

    How do I choose a heater with the right output?

    Heater output should be chosen based on the sauna room size and insulation.
    As a rule of thumb, you need 1 kW of power to heat 1 m³ of the sauna room.
    If the heater is too small it will heat the sauna too slowly, it won’t provide enough steam and it might burn out quicker. However, a heater that is slightly too powerful won’t cause trouble if it has a thermostat and it is used correctly.

    The second important thing to consider is how the sauna room is insulated. In case there are any uninsulated brick, tile, glass or log walls in the sauna room, an additional volume of 1.5 m³ for each m² of such wall should be added to the sauna room size calculation.

    You can use our sauna calculator to find out the volume of your sauna room. To calculate it yourself, multiply the height by the width and the length in meters. Then calculate the sum of uninsulated brick, tile, glass or log surfaces (m²), multiply it by 1.5 and add it to the previous result. As a result, you will have your sauna room volume in m³, based on which you can choose the suitable heater output. If the result falls between two different output values, we recommend choosing the bigger one.

    Who can install the heater?

    Only a certified electrician should install the cables and connect the heater to the power supply.

    What is included in the set?

    The set includes the heater and adjustable legs (HIVE) or wall mount (DROP). The set does not include: stones, controller, power cable.


    HUUM heaters’ minimalist and rounded design makes them some of the most elegant sauna heaters available. Thanks to an exceptionally high stone capacity they provide mild and long-lasting steam similar to traditional saunas. Little metal is used in the heaters, so the heat comes mainly from the stones and not from heated metal. This means there are more negative ions in the air, which are known to be beneficial for health. Using the heater together with aUKU Wi-FiorGSM controllerallows you to heat your sauna comfortably from your mobile phone.

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