HUUM

HUUM STEEL Mini Series 3.5kW Sauna Heater

Compact HUUM STEEL Mini 3.5 kW electric sauna heater for 106–177 cu ft rooms, 6.3 in deep, holding about 132 lb of stones

$1,576

$1,899

Save $323

In stock

Estimated delivery

7–12 days after you order

Only 2 in of clearance to the side walls
About 132 lb of stones for gentle, long-lasting steam
App control with the HUUM UKU Wi-Fi

The Sauna Mastery Protocol Digital Guide

Full-Value Freight Protection

Perfect for sauna rooms from 106 - 177 ft³

Select Stones

Required for Operation

HUUM Stones 1" to 2" (3-5 cm) | 4 Boxes
$320

Select Sauna Control

Required for Operation

HUUM UKU Local Sauna Controller | Black
$1,062
RecommendedHUUM UKU Wi-Fi Sauna Controller | Black
$1,324
HUUM UKU Wi-Fi Glass Sauna Controller
$1,724
HUUM UKU Wi-Fi Mirror Sauna Controller
$1,987

Quantity

Usually ships by UPS or FedEx; a signature is generally not required.

Secure checkout
30-day return window*
3-year manufacturer warranty

*Eligible returns must be requested within 30 days of delivery. Restocking and freight charges apply, and some items are final sale. See the Refund Policy.

Description

What is the HUUM STEEL Mini electric sauna heater?

The HUUM STEEL Mini is a compact 3.5 kW electric sauna heater (HUUM's STEEL Mini 4) from HUUM of Estonia: a stainless-steel enclosure 38.4" tall, 12.2" wide and 6.3" deep that holds about 132 lb (60 kg) of stones. It heats sauna rooms of 106–177 cu ft, stands on adjustable legs and is fixed to the wall with a HUUM bracket, runs on 240 V or 208 V, and needs a separate HUUM UKU control and four 33 lb boxes of stones.

The STEEL Mini frames the natural stones in a stainless-steel enclosure. HUUM says the large stone load gives gentle, long-lasting steam, and that an internal air tunnel speeds heating by 25% and extends the life of the heating elements. HUUM says its short safety distances, 2" to the side walls, suit even the smallest steam rooms.

How do you control the HUUM STEEL Mini?

The STEEL Mini has no built-in controls: it runs from a HUUM UKU control. UKU Local heats the sauna from the wall panel; UKU Wi-Fi adds the HUUM app, so you can start the sauna on your way home and schedule sessions ahead. Any UKU runs the STEEL Mini without an extension box. Topture also sells the STEEL Mini as a package with the UKU control and stones included.

HUUM STEEL Mini key features

Only 6.3" deep: stands on four adjustable legs and is fixed to the wall with a HUUM bracket
About 132 lb (60 kg) of 1.2–2" stones in a stainless-steel enclosure
2" of clearance to the side walls
Internal air tunnel that HUUM says speeds heating by 25%
Designed and made in Estonia
SGS listed to UL 60335-1 and CAN/CSA-C22.2 No. 60335-1

Specifications

Which sauna does the HUUM STEEL Mini fit?

The STEEL Mini is sized for sauna rooms of 106–177 cu ft at 240 V. For every square foot of uninsulated brick, tile or glass wall, add 3.3 cu ft to the room volume before choosing. HUUM's warranty does not cover a heater whose output does not match the room volume. For larger rooms, HUUM makes the HUUM STEEL in 6, 9 and 10.5 kW.

HUUM STEEL Mini 4 (3.5 kW), STEEL manual v9, Tables 1–3
HUUM model	STEEL Mini 4 (sold as 3.5 kW)
Sauna room volume	106–177 cu ft (3–5 m³) at 240 V; 106–159 cu ft (3–4.5 m³) at 208 V
Power supply	240 V or 208 V, single phase; 14.58 A at 240 V, 12.5 A at 208 V
Circuit breaker / minimum wire	20 A / 12 AWG (240 V and 208 V)
Dimensions	38.4" H × 12.2" W × 6.3" D (975 × 310 × 160 mm)
Heater weight	32 lb (14.5 kg)
Stones	About 132 lb (60 kg) of 1.2–2" (3–5 cm) stones: 4 boxes of HUUM Stones 12 (33 lb each)
Materials	Stainless steel
Made in	Estonia
Certification	SGS listed to UL 60335-1 and CAN/CSA-C22.2 No. 60335-1
HUUM part number	H1007012
Warranty	3 years private use, 1 year commercial use (HUUM); heating elements, stones and sensors are excluded

Installation

How is the HUUM STEEL Mini installed?

The STEEL Mini stands on adjustable legs and is fixed to the wall with HUUM's special bracket, with its back against the wall. HUUM strongly recommends a safety rail around the heater, which a sauna builder can make to suit the room.

HUUM's STEEL manual says the electrical connection must be made by a licensed electrician, with a circuit breaker that disconnects all poles fitted before the sauna control, a heat-resistant power cable (no PVC insulation) and a waterproof junction box no higher than 20" (50 cm) above the floor; the cable enters through the heater's bottom cover. Your electrician sizes the breaker and wire from the manual that ships with the heater and your local code.

HUUM STEEL Mini safety distances

Keep at least these distances from the HUUM STEEL Mini to walls, benches and anything that can burn. HUUM measures A from each side of the heater and B across it from wall to wall.

HUUM STEEL Mini 4 minimum safety distances (STEEL manual v9, Table 3)
A	2" (50 mm)
B	16.1" (410 mm)

A: minimum distance from each side of the heater to the wall or anything that can burn; the back of the STEEL Mini goes against the wall, where HUUM's bracket fixes it
B: minimum width between the walls on either side of the heater
At least 47.3" (1,200 mm) from the top of the heater to the ceiling

HUUM's STEEL manual gives a minimum sauna room height of 86.6" (2,200 mm), with a regular ceiling height of 86.6–91", allows only one heater per room, and calls for a sauna door that opens outward.

Stacking and caring for the stones

Wash the stones, then stack them loosely between the heating elements of the STEEL Mini and close together on the outside so no element shows. Packed too tightly, the elements overheat, wear out sooner and heat the room more slowly; a sparsely filled heater is a fire hazard. Take care not to bend the elements. HUUM recommends having a specialist lay the stones. Stones crumble with use, so HUUM suggests ceramic tile with dark grout under and around the heater.

What's Included

What's in the box with the HUUM STEEL Mini?

HUUM STEEL Mini electric sauna heater, 3.5 kW
Four adjustable legs
Installation and operation manual

What you need separately

A HUUM UKU control: UKU Local or UKU Wi-Fi (no extension box needed for the STEEL Mini)
4 boxes (132 lb) of HUUM Stones 12, 1.2–2" rounded stones
A heat-resistant power cable, connected by a licensed electrician

Documents

HUUM STEEL and STEEL Mini User Manual (US)

HUUM UKU 4.2 User Manual (US)

HUUM Stone Requirements

HUUM Limited Warranty Terms (US)

HUUM Certificate of Compliance (SGS)

Warranty

HUUM warranty periods

HUUM's limited warranty (Limited Warranty Terms and Conditions, US, v2) covers new HUUM products bought from HUUM or its authorized dealers, such as Topture, against defects in materials and workmanship. The period starts on the date the end user buys the product.

HUUM products and warranty periods (HUUM warranty terms, US, v2)
HUUM product	Private use	Commercial use
Electric sauna heaters	3 years	1 year
Wood-burning sauna stoves	3 years	1 year
Control units (UKU)	3 years	1 year
Spare parts	1 year	1 year

HUUM counts as commercial use a business using the product commercially, a private owner using it commercially, or a private owner using it for more than 1,500 hours in 12 months.

What the warranty does not cover

Heating elements of electric heaters
HUUM accessories, such as rails, reflectors, flanges, protective bedding and chimney parts
Door glass and ash grate of wood-burning stoves
Sauna stones
All controller sensors
Damage from a heater that is the wrong size for the room, from unsuitable stones, or from installation, use or maintenance that does not follow HUUM's manuals

What keeps the warranty in effect

Inspect the product when it arrives and report any visible damage within 7 days, with photos, before installing it.
Install it following HUUM's manual and local building, electrical and fire codes. An electric product must be connected by a licensed electrician, with proof of the installation.
Report a defect within 30 days of finding it. For products bought from Topture, report it to Topture, which passes the claim to HUUM and helps with troubleshooting.

Read HUUM's full Limited Warranty Terms and Conditions (US)

Step 1

Size it right

Every heater page lists the exact room size it's rated for, so you can match it to your sauna before you order.

Step 2

Get it installed

We provide the install spec sheet your electrician needs and our team is available if questions come up.

Step 3

Real löyly

With the heater, stones, and room properly matched, water on the rocks delivers the steam wave and rolling heat of a true Finnish session.

The Topture Experience

More than just a heater

Your purchase includes thoughtful extras to help you get started and enjoy your sauna with confidence.

BONUS 1

The Sauna Mastery Protocol

The session times, temperatures, and weekly rhythm that turn a sauna into a habit you keep. Covers heat-up protocols and what to expect across your first 30 sessions. Sent to your inbox after purchase.

INCLUDED

BONUS 2

Full-Value Freight Protection

Large orders ship fully insured. If freight arrives damaged, Topture helps coordinate the claim and replacement process with the carrier and manufacturer. Proper inspection and damage documentation at delivery are required. Most in-stock orders ship within 2–7 business days.

INCLUDED

Choose your options now

We thought about buying a sauna for years and finally did. We absolutely love it, especially in the winter. It’s incredibly easy to assemble with two people the whole family uses it.

Verified buyer

Ordered this sauna fall 2024 and we love it. No better feeling during a Minnesota winter. Lastly, I have to mention the customer service for this purchase has been like no other. Any questions or requests I had were addressed immediately by Topture. I got more than I expected from them and have already recommended them to several people looking for saunas. SO if you're thinking about it, JUST DO IT already..

Verified buyer

Thanks for the great service - greatly appreciated.

Verified buyer

Choosing the right sauna

Compare models from multiple sauna manufacturers based on your space, climate, capacity, preferences, and budget.

Will they help you compare alternatives, or only answer questions about the product you've already selected?

Heater & electrical fit

Get help matching the heater to the sauna volume, glass area, controls, and electrical requirements.Try our heater calculator

Ask who will check that the heater and controls are right for your installation before you order.

Authorized products

Products are sourced through authorized channels and include the applicable manufacturer warranty.View independent listings

Verify that the retailer is authorized for the brand and that your manufacturer warranty will be valid.

Freight delivery

We help coordinate heavy-freight delivery and provide guidance on receiving and inspecting your shipment.

Ask how the order ships, how it will be unloaded, and what happens if freight arrives damaged.

Installation information

We help provide the manuals, specifications, clearances, and electrical information your installer may need.

Find out what documentation and project support will be available after checkout.

After the sale

Questions after delivery? We help with troubleshooting, documentation, warranty coordination, and manufacturer support.Read customer reviews

Ask who you will actually contact if something doesn't work after the order arrives.

463 Customer Reviews

Product and store reviews from Topture customers, collected by Judge.me.

Lifetime Expert Support

Same team before and after the sale, from sizing to warranty support.

Authorized HUUM Retailer

Sold by Topture, with the applicable manufacturer warranty.

Full-Value Freight Protection

Freight damage? We help coordinate the claim and replacement process.

STILL UNSURE?

Frequently Asked Questions

What comes with the HUUM STEEL Mini heater, and what else does it need to run?

The HUUM STEEL Mini heater ships with four adjustable legs and HUUM's installation and operation manual. It does not run on its own: HUUM lists a UKU control, about 132 lb (60 kg) of 1.2–2 in stones and a heat-resistant power cable as what the heater additionally needs. Topture offers the HUUM UKU control and four 33 lb boxes of HUUM Stones 12 as options with the heater, and the HUUM STEEL Mini package combines the heater, a UKU control and the stones in one order.

What size sauna is the HUUM STEEL Mini for?

The HUUM STEEL Mini, called the STEEL Mini 4 in HUUM's manual, is a 3.5 kW heater for sauna rooms of 106–177 cu ft at 240 V, or 106–159 cu ft at 208 V. For every square foot of uninsulated brick, tile or glass wall, add 3.3 cu ft to the room volume before choosing. The room must be at least 86.6 in tall. For larger rooms, HUUM makes the STEEL in 6, 9 and 10.5 kW. HUUM's warranty does not cover a heater whose output does not match the room.

What electrical supply does the HUUM STEEL Mini need?

The HUUM STEEL Mini runs on 240 V or 208 V, single phase; HUUM's manual gives only those two connections. It says the heater draws 14.58 amps at 240 V and 12.5 amps at 208 V, calls for a heat-resistant power cable (no PVC insulation), and requires a licensed electrician to make the connection. Your licensed electrician sizes the breaker and wire from the manual that ships with the heater and your local code.

Which control works with the HUUM STEEL Mini?

HUUM pairs the HUUM STEEL Mini with its UKU control, which runs heaters up to 11 kW on its own, so the STEEL Mini needs no extension box. The UKU Local is run from its wall panel only, with no app. The UKU Wi-Fi models add the app over 2.4 GHz Wi-Fi, so you can start the sauna on your way home. The black CLASSIC panel mounts outside the sauna room, while the black glass and mirror-finish glass panels are recessed into the wall and may go inside the sauna room, away from the heater, with the top edge no higher than 40 in above the floor and at least 20 in from any exhaust vent. HUUM's UKU manual requires the door sensor supplied with the control.

How is the HUUM STEEL Mini installed?

The HUUM STEEL Mini stands on adjustable legs and is fixed to the wall with HUUM's special bracket, with its back against the wall. HUUM's manual keeps it at least 2 in from the walls at its sides, with at least 16.1 in between those walls, and 47.3 in from the top of the heater to the ceiling, in a room at least 86.6 in tall. HUUM strongly recommends a safety railing around the heater, and a licensed electrician must make the electrical connection.

How do you load and maintain the stones in a HUUM STEEL Mini, and can you pour water on them?

The HUUM STEEL Mini takes about 132 lb (60 kg) of natural sauna stones 1.2–2 in across; four 33 lb boxes of HUUM Stones 12, which are rounded olivine diabase, cover it. HUUM's manual says to wash the stones, then stack them loosely between the heating elements so air can circulate and close together on the outside so no element shows. HUUM recommends a specialist lay the stones. Make steam with tap water only, never with a hose, and never pour undiluted sauna essences onto the stones, which can ignite. Stones crumble with use, so HUUM suggests ceramic tile with dark grout under the heater.

What problems do HUUM STEEL Mini owners run into, and how are they avoided?

Most HUUM STEEL Mini problems that HUUM's manual warns about start with the stones. Stones stacked too tightly make the heating elements overheat, which shortens their life and slows heating; a sparsely filled heater is a fire hazard; and the elements must not be bent or left visible. HUUM's warranty does not cover the heating elements. On first use, insulation resistance can read low from moisture picked up in storage; it clears after 1–2 hours of heating. A heater closer to flammable materials than the minimum distances is a fire hazard, and one sized wrongly for the room loses its warranty.

Who makes the HUUM STEEL Mini, and what is it made of?

The HUUM STEEL Mini is made by HUUM in Estonia. Its body is a stainless-steel enclosure, which HUUM says adds a modern look to the sauna. HUUM holds an SGS North America certificate of compliance for the STEEL Mini to UL 60335-1 and CAN/CSA-C22.2 No. 60335-1, the US and Canadian safety standards for household appliances. It is 38.4 in tall, 12.2 in wide and 6.3 in deep, and weighs 32 lb.

What warranty does the HUUM STEEL Mini have?

HUUM's manufacturer warranty covers the HUUM STEEL Mini for 3 years of private use or 1 year of commercial use. It excludes the heating elements, the sauna stones, sensors and HUUM accessories, and it does not apply when the heater is the wrong size for the room or was not installed by a licensed electrician. HUUM's warranty applies to products bought from HUUM or its authorized dealers; Topture is an authorized HUUM dealer and helps with troubleshooting and warranty coordination. Report any transport damage within 7 days of delivery.

How does the HUUM STEEL Mini compare with the HUUM CLIFF Mini?

The biggest difference is the look. The HUUM STEEL Mini frames its stones in a stainless-steel enclosure, while the CLIFF Mini shows them between stainless-steel ribs. Both are 3.5 kW heaters for rooms of 106–177 cu ft, hold about 132 lb of 1.2–2 in stones, stand 38.4 in tall and 6.3 in deep, and fix to the wall with HUUM's bracket, per HUUM's manuals. The STEEL Mini is wider, 12.2 in against the CLIFF Mini's 10.6 in, and needs slightly less side clearance, 2 in against 2.36 in.

Where can you buy the HUUM STEEL Mini from an authorized dealer?

Topture is an authorized HUUM retailer, listed in HUUM's own dealer directory, and sells the HUUM STEEL Mini. The heater can be ordered with the UKU control and HUUM Stones 12, or as the HUUM STEEL Mini package that combines the heater, a UKU control and the stones sized for it. Topture adds Lifetime Expert Support, help with troubleshooting and warranty coordination, free shipping on orders over $200 within the continental US, financing through Shop Pay Installments at checkout, and a 30-day return window.

What does a HUUM STEEL Mini cost in total, delivered?

The delivered cost of a HUUM STEEL Mini from Topture is the heater price plus the parts it needs to run: a HUUM UKU control and four 33 lb boxes of stones. Topture has free shipping on orders over $200 within the continental US, so a STEEL Mini order ships free there. The HUUM STEEL Mini package combines heater, UKU and stones at exactly the sum of the three parts. Budget separately for a licensed electrician's work and for the safety railing HUUM recommends. Compare delivered totals, because some listings price the heater without its control and stones. Financing is available through Shop Pay Installments at checkout.

General Topture Questions

Where are you located, and where do you ship from?

Topture is an online retailer serving customers in the contiguous United States. The company is Topture LLC, a Wyoming limited liability company, and its registered business address is 30 N Gould St, Ste N, Sheridan, WY 82801.

Orders ship from manufacturer and distributor warehouses in the U.S. and Canada, and some products ship directly from the manufacturer in Europe. Each product page shows its estimated delivery time.

How much is shipping?

Orders over $200 ship free within the continental United States. Orders under $200 carry a small shipping fee.

Two exceptions: SaunaLife and ThermaSol products carry a freight charge at any order value, and sauna stones ordered without a heater ship at $60 per box because of their weight.

Every charge is shown at checkout before you pay.

Do you provide financing?

Absolutely! To view your financing offer, simply select Shop Pay Installments as your payment method at Step 3 of checkout.

You'll need to enter a debit card to receive your offer, but don’t worry—you can still back out before completing the purchase.

How long will it take for my items to arrive?

If your order is in stock, most orders ship within 2–7 business days of purchase. Transit time then depends on the distance from the warehouse and, for freight, on booking a delivery appointment.

For custom, pre-order or made-to-order items, the estimated delivery time frame is listed on the product page. Delivery dates are estimates, so please don't book installation labor until your order has arrived and been inspected.

What happens after I place my order?

As soon as you place your order, you'll receive a confirmation email with your order details—be sure to keep it for your records. Once your order ships, you'll receive another email with tracking information.

For freight deliveries, the carrier will call or text you to schedule an appointment once the shipment reaches their local terminal. Someone needs to be there to inspect the shipment and sign for it. Smaller parcels arrive by UPS or FedEx without an appointment.

Is there a warranty?

Yes. Products purchased through Topture include the applicable manufacturer’s warranty, subject to the manufacturer’s terms. You’ll find the warranty details for each product under the "Warranty" tab on its product page, and we help with troubleshooting and warranty coordination if an issue comes up.

Do you have a showroom?

We don’t have a showroom — we sell online. Our team is available by phone, email and chat to help you compare models, sizes and heaters, and we can send dimensions, installation manuals and electrical requirements before you buy.

Where do you deliver to?

We deliver throughout the 48 contiguous states, with curbside freight delivery for large items. Free shipping and standard rates apply there only. Alaska, Hawaii, Puerto Rico, other U.S. islands and Canada are quoted separately, depending on the brand and model. We can't ship freight or oversized items to P.O. boxes.

Do you ship internationally?

International Shipping

For many products, yes, including to Canada, by custom quote. Email contact@topture.com with the product and your address before you order; availability and cost depend on the brand and model. Any duties, taxes and customs fees are your responsibility.

Shipping to Hawaii, Alaska, and Puerto Rico

Free shipping applies to the continental United States only. Shipping to Alaska, Hawaii, Puerto Rico and other U.S. islands is quoted separately and depends on the brand and model. Email contact@topture.com for a quote before you order.

Your electric sauna heater, done the right way.

Only 2 in of clearance to the side walls
About 132 lb of stones for gentle, long-lasting steam
App control with the HUUM UKU Wi-Fi

The Sauna Mastery Protocol Digital Guide

Full-Value Freight Protection

Secure checkout
30-day return window*
3-year manufacturer warranty

*Eligible returns must be requested within 30 days of delivery. Restocking and freight charges apply, and some items are final sale. See the Refund Policy.

HUUM STEEL Mini Series 3.5kW Sauna Heater