What size sauna is the HUUM STEEL Mini 3.5kW best for?

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Is this the same as the HUUM STEEL Mini 4?

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Does the HUUM STEEL Mini include the UKU control?

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Does the HUUM STEEL Mini include sauna stones?

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Is this a complete heater package?

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Why buy the HUUM STEEL Mini from NW Immersion?

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HUUM STEEL Mini 3.5 kW 240V Electric Sauna Heater - Complete Package Options - NW Immersion

HUUM STEEL Mini 3.5kW Electric Sauna Heater | Complete Package Options

$1,576.00

SKU: H1007012 By HUUM

Authorized HUUM Dealer • Full Manufacturer Warranty Included

Slim Design. Soft Steam. Built for Compact Saunas.

The HUUM STEEL Mini 3.5kW Electric Sauna Heater is a compact wall-mounted sauna heater designed for smaller sauna rooms where space, safety clearances, and refined design all matter.

Also listed as the HUUM STEEL Mini 4, this model is engineered for sauna rooms approximately 106–177 cubic feet and features HUUM’s signature slim stainless steel profile, exceptionally short safety distances, and a large stone capacity for its size. Despite its compact footprint, the STEEL Mini holds approximately 133 lbs of sauna stones, helping create soft, lasting heat and authentic löyly in smaller home sauna spaces.

The HUUM UKU control system and HUUM sauna stones are required for operation and can be added below to build your complete heater package.

✓ Premium 3.5kW Electric Sauna Heater
✓ Best for Sauna Rooms Approx. 106–177 Adjusted Cu. Ft.
✓ Compact Wall-Mounted Design for Smaller Saunas
✓ Exceptionally Short Safety Distances
✓ Large 133 lb Stone Capacity for Soft Steam
✓ Stainless Steel Construction
✓ Compatible with HUUM UKU Controls

Build Your Complete HUUM STEEL Mini Heater Package

The HUUM STEEL Mini 3.5kW heater requires a compatible HUUM UKU control system and HUUM sauna stones for operation. Use the add-ons below to build the correct package for your sauna installation.

HUUM UKU Control System — Required for Operation

Required to operate your HUUM heater, with precise temperature control and optional WiFi app access depending on the UKU model selected.

View details

HUUM Stones 12 Sauna Stone Package — Required for Operation

Required for safe heater operation, steady heat retention, and authentic löyly. This heater requires 4 boxes of HUUM Stones 12, totaling approximately 132 lbs of sauna stones for proper operation.

View details

Complete Your Sauna Experience

Thoughtfully selected essentials designed to enhance comfort, preserve your investment, and help you enjoy the authentic Finnish sauna experience for years to come.

View details

Enhance Your Wellness Experience

Upgrade every sauna session with advanced red & near-infrared therapy. Sauna-rated up to 215°F for safe, seamless use inside traditional saunas.

View details

1

Purchase with Confidence

Premium Craftsmanship & Manufacturer Warranty
Expert Guidance Before, During & After Delivery
Personalized Delivery Planning & Coordination
Real Sauna Specialists Just a Call, Text or Chat Away

Talk With a Sauna Specialist

Our team helps customers nationwide with sauna selection, site preparation, delivery planning, and installation guidance.

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Product Overview

A Compact HUUM Heater with Serious Stone Capacity

The HUUM STEEL Mini 3.5kW Electric Sauna Heater is designed for compact sauna rooms that need efficient heat, a slim footprint, and the soft steam experience HUUM is known for.

Its narrow wall-mounted design makes it ideal for small home saunas, compact sauna kits, wellness rooms, and tight layouts where every inch matters. The STEEL Mini is especially helpful when safety clearances are a concern, since the heater is engineered with exceptionally short safety distances and a compact stainless steel body.

What makes the STEEL Mini stand out is its stone capacity. While many smaller electric sauna heaters hold a limited amount of stone, the STEEL Mini holds approximately 133 lbs, allowing for softer, longer-lasting heat and a more satisfying löyly experience when water is poured over the stones.

The heater also uses HUUM’s internal air duct design, which helps improve airflow and heat-up performance. Bathing Brands lists the internal air duct as helping the heater heat up to 25% faster, while still supporting the mild, lasting steam created by the large stone mass.

Why You'll Love it!

Designed for Smaller Sauna Rooms

The STEEL Mini is built specifically for compact sauna rooms where a full-size heater would take up too much space or require larger clearances.

Slim Wall-Mounted Design

Its narrow stainless steel body mounts to the wall, helping preserve floor space and create a cleaner, more open sauna layout.

Large 133 lb Stone Capacity

The STEEL Mini holds an impressive amount of sauna stones for its size, helping create soft, steady heat and a more traditional löyly experience.

Authentic Löyly

Pour water over the heated stones to create steam, humidity, and the atmosphere that define a traditional Finnish-style sauna experience.

Short Safety Distances

The compact STEEL Mini is engineered with short safety distances, making it a strong choice for small sauna rooms and tight installations.

Built-In Air Duct for Faster Heat-Up

The optimized internal air duct helps improve airflow and heat-up performance, with Bathing Brands noting up to 25% faster heat-up.

HUUM UKU Control Compatibility

Pair your STEEL Mini with a required HUUM UKU control system for precise temperature control and optional WiFi app access depending on the selected UKU model.

Designed and Made in Estonia

The STEEL Mini is designed, engineered, and made in Estonia with HUUM’s modern sauna design language and stainless steel construction.

What Makes HUUM STEEL Mini Different?

Small Footprint. Big Stone Mass. Softer Steam.

The HUUM STEEL Mini is built for small sauna rooms, but it does not feel like a basic small-room heater.

Its slim vertical body takes up very little space, while the large exposed stone capacity helps create the softer steam and longer heat retention usually associated with larger heaters. Direct contact between the stones and heating elements helps transfer heat efficiently, while the exposed stone mass supports a more satisfying löyly experience.

For compact saunas where space is limited but the sauna experience still matters, the STEEL Mini offers an excellent balance of design, performance, and practicality.

What’s Included

HUUM STEEL Mini 3.5kW Sauna Heater

Compact wall-mounted electric sauna heater with slim stainless steel construction.

Wall Fastening Bracket

Included wall bracket for proper wall-mounted installation.

Installation & Operation Manual

Manufacturer documentation included for installation, safety clearances, operation, and maintenance.

Manufacturer Warranty Information

Warranty documentation included with the heater.

Required but Sold Separately

HUUM UKU Control System
HUUM Stones 12 Sauna Stone Package

The standalone STEEL Mini heater does not include the UKU control system or sauna stones. Both are required for operation and should be selected from the package options above.

Specifications

General

Brand: HUUM

Model: STEEL Mini 4 / STEEL Mini 3.5

SKU: H1007012

Product Type: Electric Sauna Heater

Mounting Style: Wall-Mounted

Power Rating: 3.5kW

Primary Fuel: Electric

Construction: Stainless Steel

Control Type: External HUUM UKU control required

Recommended Use: Compact traditional sauna rooms, small home saunas, wellness rooms, and small sauna kits

Country of Origin: Estonia

Sauna Room Sizing

Recommended Sauna Room Size: Approx. 106–177 cu. ft.

Important Sizing Note: Glass, tile, stone, brick, concrete, log walls, and other cold surfaces can increase adjusted room volume.

Final heater sizing should always account for insulation quality, glass area, stone or tile surfaces, ceiling height, ventilation, and overall sauna design.

Electrical

Supply Voltage: 240V

Phase: Single Phase

Control Type: HUUM UKU control required

Professional Installation: Required by a licensed electrician

Power Cable: Confirm with official HUUM manual and licensed electrician

Always confirm final breaker, wiring, control compatibility, and installation requirements with the official HUUM installation manual and your licensed electrician.

Stone Capacity

Stone Capacity: Approx. 132 lbs

Required Stone Package: 4 boxes of HUUM Stones 12

Stone Size: Approx. 1"–2" / 3–5 cm

Stones Required: Yes

Stones Included with Base Heater: No

Dimensions & Weight

Width: Approx. 12.6" / 320 mm

Depth: Approx. 6" / 150 mm

Height: Approx. 38.4" / 975 mm

Heater Weight: Approx. 32 lbs / 14.5 kg

Package Details

Sales Unit: 1 heater

Controller Included: No

Stones Included: No

Wall Fastening Bracket Included: Yes

Installation Manual Included: Yes

Resources & Guides

Resources- Click Links Below

HUUM Steel Manual

HUUM Steel Mini Spec Diagram

HUUM Stone Requirements

Elements Required

Huum warranty

Size Your Sauna

Click Here for Video on the HUUM UKU Main Module Installation

Click Here for Video on the UKU Controller Installation

Click Here for Video on Connecting to the HUUM UKU WiFi

Installation Notes

Professional Installation Required

The HUUM STEEL Mini 3.5kW must be installed by a licensed electrician and in accordance with the official HUUM installation manual, local electrical code, and all required safety clearances.

Because the STEEL Mini requires a separate UKU control system, sauna stones, correct wiring, proper wall mounting, and required clearances, installation should be planned before the sauna is completed whenever possible.

Before ordering or installing, confirm:

Sauna room adjusted cubic footage
UKU control selection
Stone package requirements
Electrical requirements
Heater placement and clearances
Wall mounting surface
Ventilation and bench layout
Whether a safety rail is recommended for your installation

Always refer to the official manufacturer documentation before installation.

HUUM's YouTube channel has a lot of helpful videos

Shipping & Delivery

Free Shipping: This order qualifies for free shipping within the contiguous United States.
Processing Time: In-stock items typically leave the warehouse within 1–3 business days. This is the processing period before transit, not the final delivery time.
Confirm Availability: Inventory can change quickly. Please call, text, or email NW Immersion before ordering if you need confirmation of current stock or have a specific delivery deadline.
Multiple Packages: The heater, sauna stones, controls, and accessories may ship in separate boxes or on separate pallets. Packages may arrive on different days.
Tracking: Tracking information will be emailed for each shipment as soon as it leaves the warehouse.
Inspect Upon Arrival: Check every package for visible damage before accepting delivery. Photograph any damage and contact NW Immersion promptly so we can assist.

Questions about availability, delivery, heater sizing, controls, or installation requirements? Our U.S.-based sauna specialists are available by phone, text, or email.

Warranty

Click Here for the HUUM Manufacturer Warranty

HUUM Manufacturer Warranty

Backed by HUUM’s manufacturer warranty when installed and used according to HUUM’s official instructions.

Warranty coverage may vary by component, installation type, use environment, maintenance, chimney connection, and fuel use. Sauna stones, chimney components, and accessories may each carry their own warranty terms.

As an Authorized HUUM Dealer, NW Immersion is here to help with stove sizing, product selection, delivery coordination, troubleshooting, warranty guidance, and long-term support.

Always refer to the official HUUM warranty documentation included with your stove for complete terms and final coverage details.

Frequently Asked Questions

The HUUM STEEL Mini 3.5kW is best for compact sauna rooms approximately 106–177 cubic feet. If your sauna has glass, tile, stone, brick, concrete, log walls, or other cold surfaces, your adjusted cubic footage may be higher than the basic room size.

Yes. This product is commonly listed as the HUUM STEEL Mini 4, while the heater power is listed as 3.5kW for the 240V configuration. Bathing Brands lists the model as STEEL Mini 4 and the SKU as H1007012.

No. The HUUM UKU control system is required for operation and sold separately. You can choose a UKU Local or UKU WiFi control option when building your package.

No. Sauna stones are required for operation and sold separately. The STEEL Mini requires 4 boxes of HUUM Stones 12, totaling approximately 132 lbs of stones.

The base product is the HUUM STEEL Mini electric sauna heater. Package options are available so you can add the required HUUM UKU control, required HUUM sauna stones, and optional safety rail.

Yes. The HUUM STEEL Mini is designed for traditional sauna use. Pouring water over properly heated sauna stones creates löyly, the steam and humidity that define an authentic sauna experience.

Yes, when paired with a HUUM UKU WiFi control. The heater itself requires a separate UKU control, so WiFi capability depends on which UKU control option you select.

This product is listed as a 240V electric sauna heater. Final breaker, wiring, control installation, and code requirements should always be confirmed with the official HUUM installation manual and your licensed electrician.

NW Immersion helps you choose the correct heater size, UKU control, sauna stones, safety accessories, and installation components before you order. As an Authorized HUUM Dealer and real sauna specialist, we can help with sizing, package configuration, delivery planning, installation guidance, and long-term support.

HUUM STEEL Mini 3.5kW Electric Sauna Heater | Complete Package Options

Authorized HUUM Dealer • Full Manufacturer Warranty Included

Slim Design. Soft Steam. Built for Compact Saunas.

Build Your Complete HUUM STEEL Mini Heater Package

Maximize your savings. Pay with HSA or FSA.

Purchase with Confidence

Talk With a Sauna Specialist

A Compact HUUM Heater with Serious Stone Capacity

Designed for Smaller Sauna Rooms

Slim Wall-Mounted Design

Large 133 lb Stone Capacity

Authentic Löyly

Short Safety Distances

Built-In Air Duct for Faster Heat-Up

HUUM UKU Control Compatibility

Designed and Made in Estonia

What Makes HUUM STEEL Mini Different?

Small Footprint. Big Stone Mass. Softer Steam.

HUUM STEEL Mini 3.5kW Sauna Heater

Wall Fastening Bracket

Installation & Operation Manual

Manufacturer Warranty Information

Required but Sold Separately

General

Sauna Room Sizing

Electrical

Stone Capacity

Dimensions & Weight

Package Details

Resources- Click Links Below

Installation Notes

Professional Installation Required

HUUM Manufacturer Warranty

Frequently Asked Questions

What size sauna is the HUUM STEEL Mini 3.5kW best for?

Is this the same as the HUUM STEEL Mini 4?

Does the HUUM STEEL Mini include the UKU control?

Does the HUUM STEEL Mini include sauna stones?

Is this a complete heater package?

Can I pour water on the stones?

Is the HUUM STEEL Mini WiFi compatible?

What electrical service does the HUUM STEEL Mini require?

Why buy the HUUM STEEL Mini from NW Immersion?

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