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Whether you’re choosing one component or planning the whole room, small details can become expensive problems once installation begins. We know the products we sell and the questions to ask early, helping catch mismatched components, overlooked requirements, and installation issues while they are still easy to fix.

Our job does not end when your order ships. We stay available through installation and beyond. If something needs attention, we stay involved, work the problem, and help see it through.

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Sauna and heater customers also receive free shipping on sauna accessories for life.

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Includes

What Is Included

3.5 KW

Included with purchase

3.5 kW sauna heater wall fastening bracket installation and operation manual.

Required separately

UKU control, 133 lb stones (quantity 4 × 33 lb of 1" - 2" stones boxes).

Contents vary by configuration. Check the row for the option selected above.

Technical Specifications

Model & Application

Model & Application
Brand	HUUM
Catalog Product	HUUM STEEL Mini Electric Sauna Heater \| 3.5 kW
Heater Type	Electric sauna heater
Model Number	STEEL MINI 4
SKU / Part Number	H1007012

Sauna Sizing

Sauna Sizing
Maximum Room Volume	177 ft³
Minimum Room Volume	106 ft³

Electrical

Electrical
Minimum Circuit	20 A
Phase	1 phase
Rated Current	14.58 A
Supply Voltage	240 V
Wire Size	12 AWG

Dimensions & Weight

Dimensions & Weight
Assembled Dimensions	12.6" W x 6" D x 38.4" H
Heater Depth	6.3 in
Heater Height	38.39 in
Heater Weight	32 lb
Heater Width	12.21 in
Minimum Host-Room Height	85.63 in
Product Weight	32 lbs

Installation Clearances

Installation Clearances
Ceiling-Clearance Reference Height Above Finished Floor	38.39 in
Ceiling-Clearance Reference Plane	Top Of Rocks
Left-Side Clearance	1.97 in
Right-Side Clearance	1.97 in
Combustible Side Clearance	1.97 in
Minimum Installation Envelope Width	16.14 in
Top of Rocks Above Finished Floor	38.39 in

Included & Required

Included & Required
Included Components	3.5kW sauna heater Wall fastening bracket Installation and operation manual 5-Year limited warranty (excluding elements)
Required, Not Included	UKU Control, 133 lbs stones (Qty 4 x 33 lbs of 1" - 2" stones boxes)

Certifications

Certifications
Certifications & Listings	CE, IPX4, SGS

Warranty

Warranty
Residential Warranty	3-Year Limited Residential Warranty and 1-Year Limited Commercial Warranty (Excluding Elements)

Use the attached current manual and a qualified installer for final sizing, wiring, clearances, venting, and local-code compliance.

How It Fits

How This Product Fits the System

What it is used for

An electric sauna heater that heats the sauna room and stone mass for traditional löyly. Choose the output from adjusted room volume, then match the exact voltage, phase, circuit, controls, stones, clearances, and ventilation.

What to plan

Size from adjusted sauna volume, including the effect of glass, masonry, and other uninsulated surfaces; do not size from floor area alone.
Match the selected model's power or fuel, voltage, phase, circuit, wire, control, stone, and venting requirements before ordering.
Treat clearances, ceiling reference planes, ventilation, guarding, floor protection, and service access as one room-layout decision.
Follow the current installation manual and use a qualified installer.

Required separately

Complete the system with these items.

HUUM UKU Sauna Control | Local & Wi-Fi Packages Required for operation; match the version and quantity to this selection.
HUUM Sauna Stones 1-2 in | 33 lb Box for CLIFF & STEEL Required for operation; match the version and quantity to this selection.

Designed to work with

Model-specific replacements and compatible system components.

HUUM 75-Foot UKU Extension Cables | Control & Sensor Designed for the same heater or control system; confirm compatibility with the selected model.
HUUM UKU Extension Box Designed for the same heater or control system; confirm compatibility with the selected model.
HUUM UKU Panel Designed for the same heater or control system; confirm compatibility with the selected model.
HUUM UKU-TEMP-SNSR Designed for the same heater or control system; confirm compatibility with the selected model.
HUUM UKU Wi-Fi Main Module | SP0030 Designed for the same heater or control system; confirm compatibility with the selected model.
HUUM UKU Door Sensor | SP0032 Designed for the same heater or control system; confirm compatibility with the selected model.
HUUM UKU Control Panel Cable | 33 ft, SP0035 Designed for the same heater or control system; confirm compatibility with the selected model.
HUUM UKU Surface Mounting Frame | UKU Glass, Mirror and Gold Designed for the same heater or control system; confirm compatibility with the selected model.

Sauna packages that offer this heater

Available heater options for these sauna packages.

Auroom Cala Glass Mini 1-Person Indoor Sauna With Floor Available with this sauna package; confirm the current selection and installation requirements.
Auroom Familia - Indoor Sauna Kit With Floor Available with this sauna package; confirm the current selection and installation requirements.

Other heater options

Compare these options; sizing, power, controls, clearances, and stones may differ.

Harvia Vega Compact (1.9KW, 3.5KW) A related heater option, not an interchangeable replacement; re-check sizing, power, controls, clearances, and stones.

Attachments

Current US/CA Manual - HUUM UKU 4.2 - v1

Current installation and operation manual for the UKU 4.2 controllers sold by Sauna Marketplace. Owners of older UKU 4.1 controllers should use the legacy manual that matches their installed hardware.

View PDF Download

Current US Manual - HUUM STEEL / STEEL Mini - H1006L03 v9 / content v4

Current official HUUM US installation and operation manual. Applies to STEEL Mini 4 and STEEL 6, 9, and 11. This local target was added after STEEL Mini became a separate Woo parent; production publication still requires an explicit --apply run and byte-for-byte verification.

View PDF Download

Legacy manuals for older installations

Use these only when the document revision matches the installed product.

Legacy US/CA Manual - HUUM UKU 4.1 - for older installations

Legacy manual for existing UKU 4.1 installations only. Sauna Marketplace now sells UKU 4.2. For a new controller, use the UKU 4.2 manual.

View PDF Download

Gallery

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HUUM STEEL Mini Electric Sauna Heater | 3.5 kW

HUUM STEEL Mini is a low-profile small sauna heater that stands on adjustable legs against the wall and is secured with HUUM’s special bracket. Its 3.5 kW output covers 106–177 cubic feet, while approximately 132 lb of stones deliver mild, long-lasting steam. UKU control and four boxes of 1–2-inch stones are required and sold separately.

Build A Quote:

Clear

Choose a HUUM UKU controller (required)

Your heater will not run without a UKU. Local mounts outside the hot room and runs the sauna from its own panel. Wi-Fi does the same and adds scheduling and remote start from the HUUM app, which is what you want when the sauna is not ten steps from the couch. Every finish below is the same controller underneath, so pick on looks and budget. Already own a UKU? Take the first option and we will check yours against this heater before anything ships.

I already own a compatible HUUM UKU controller package

UKU Wi-Fi, Black (recommended) +$1,324.00

UKU Wi-Fi, Black (recommended)(+$1,324.00)

Add-Ons

75′ Cable Run for Temp Sensor, Door Sensor (+$176.00)

75 Cable Extension for Controller (+$143.00)

Spare Set of Heating Elements (+$332.00)

Add the required stones: STEEL Mini 3.5 kW

The STEEL Mini 3.5 kW holds about 132 lb of 1 to 2 inch stones, and stones do not come in the box with the heater. That comes to 4 boxes. Stack them loosely so air can move between them and the elements stay covered, and plan on restacking once a year.

I already have the approved 1–2 inch stones for STEEL Mini 3.5 kW

4 × 33-lb boxes of HUUM STONES 12 (132 lb supplied)(+$320.00)

Free Quote For Sauna Wood

Did you know Sauna Marketplace specializes in premium Sauna Woods? Whether you’re looking for the highest grade material, a specific look, or to save money we have something for you.

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Fulfillment Partner:

Sauna Marketplace

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STEEL Mini brings HUUM’s slim architectural design to compact sauna rooms. Its low-profile 12.2-inch-wide by 6.3-inch-deep body stands on adjustable legs against the wall and is secured with HUUM’s special wall bracket. The internal air tunnel supports quick, even heating while approximately 132 lb of stones provide gentle, long-lasting steam.

HUUM UKU control and sauna stones are required and sold separately. Electrical installation must be completed by a qualified electrician using the current U.S. manual.

Expert help that stays with you

Our job does not end when your order ships. We stay available through installation and beyond. If something needs attention, we stay involved, work the problem, and help see it through.

Sauna and heater customers also receive free shipping on sauna accessories for life.

Includes