HUUM STEEL 6 kW Electric Sauna Heater (240 V)

A slim stainless steel heater that holds about 330 lb of stones for rooms of 177 to 318 ft³. SGS’s own database lists it to UL 60335-1 and CSA E60335-2-53. It needs a UKU control and stones, and the warranty leaves out the elements.

Best for Builders of a small to medium home sauna who want soft, long-lasting steam from a large stone mass and accept an SGS listing and a warranty that leaves out the elements.

Our rating: Good (4.3 of 5)
Price range: Premium
Verified marks: SGS North America certificate SGSNA/20/SUW/00067X (UL 60335-1, CAN/CSA C22.2 No. 60335-1 and CAN/CSA E60335-2-53) naming STEEL 6, STEEL 9 and STEEL 11; SGS’s own certificate page shows it valid, issued 2025-06-27, and the heater was evaluated with the HUUM UKU control
Size: Floor-standing tower, 12.6 in W x 12.6 in D x 38.4 in H, 33 lb; 6 kW on 240 V (25 A load, 30 A breaker, 10 AWG); rooms of 177 to 318 ft³ (5 to 9 m³); holds about 330 lb (150 kg) of 3 to 5 cm stones
Made in: Estonia

approx. $3,895 as a package with a UKU local control and 330 lb of stones ($2,033 for the heater alone), SaunaHeaters.com, 2026-11-03

See it on HUUM’s site → (opens in a new tab)

We are not affiliated with HUUM. This link goes to the maker’s own page, with no tracking code. How we're funded.

Also sold at SaunaHeaters.com (retailer) ($3,895 as a package with a UKU local control and 330 lb of stones; approx. $4,157 with the UKU Wi-Fi control; approx. $2,033 for the heater alone), Sauna Place (retailer) ($2,033 for the heater alone), My Sauna World (retailer) ($2,033 for the heater alone) , and 1 more.

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How we evaluated it

How it scores Our rating, metric by metric Good, 4.3 of 5

Heat & steam 25% of the rating 5 of 5

Holds about 330 lb of stones in direct contact with the elements for 177 to 318 ft³, the largest stone mass of any heater we list, and the UKU control a dealer sells with it sets 104 to 230 °F.
Build 15% of the rating 5 of 5

A stainless steel enclosure and stainless elements, made in Estonia, with no painted or plastic part stated on the hot side.
Safety listing 25% of the rating 5 of 5

SGS North America, an OSHA-recognized lab, lists the STEEL 6 to UL 60335-1 and CSA E60335-2-53 with the UKU control and its own page shows the certificate valid, though HUUM’s manual cites only the European standard.
Durability 20% of the rating 3 of 5

HUUM’s terms give 3 years for private use but exclude heating elements, stones and sensors, a US dealer says claims now go to HUUM in Estonia, and some Trustpilot reviewers report failed elements and refused claims.
Value 15% of the rating 3 of 5

About $3,895 for a working set of heater, local control and 330 lb of stones, or $2,033 for the heater alone, for rooms of 177 to 318 ft³.

The rating, 4.3 of 5, is the weighted average of these scores. See how we rank sauna heaters and our standard.

Where to buy Stores and the prices we saw 4 stores

SaunaHeaters.com (retailer) (opens in a new tab) approx. $3,895 as a package with a UKU local control and 330 lb of stones; approx. $4,157 with the UKU Wi-Fi control; approx. $2,033 for the heater alone. A retailer, not the maker. The package has the heater, a UKU control and 330 lb of round 3 to 5 cm stones. Its page gives HUUM’s 3-year residential warranty, excluding elements, and says it ships in 1 to 3 business days.
Sauna Place (retailer) (opens in a new tab) approx. $2,033 for the heater alone. A retailer, not the maker. Heater only: the control and stones are sold separately. Listed as in stock (3 available) on 2026-11-03.
My Sauna World (retailer) (opens in a new tab) approx. $2,033 for the heater alone. A retailer, not the maker. Heater only. Its page says it sells from the factory on a layaway plan with 50% down, refundable before the order ships.
Finnish Sauna Builders (retailer) (opens in a new tab) approx. $4,566 as the Ultimate Package: heater, 330 lb of stones, safety railing and UKU Black Wi-Fi control. A retailer, not the maker. The page gives a 5-year limited warranty excluding elements, but also says the dealer can no longer handle HUUM parts and warranty claims, which go to HUUM in Estonia.

Prices as we saw them on November 3, 2026. They change often. These links carry no tracking code and earn us nothing.

What it’s made of What touches your food, water, skin or air 5 materials

Stainless steel enclosure around the elements and stones (the maker names a stainless steel enclosure)
Stainless steel, industrial-quality heating elements (SaunaHeaters.com says so; the maker does not state the element material)
Built-in air tunnel, adjustable legs and floor brackets in the box; the heater weighs 33 lb
Needs a HUUM UKU control, local or Wi-Fi through the HUUM app, sold separately; the console is black plastic, glass, mirror or wood
Needs about 330 lb (150 kg) of 3 to 5 cm sauna stones, not included in the heater price; the dealer’s package supplies round olivine diabase stones

Who tested it What each test found, and who paid for it 1 test

Paid certification SGS North America (certificate for HUUM heaters) June 2025

SGS’s own certificate page, reached through the QR code on the certificate, shows SGSNA/20/SUW/00067X as valid, issued 2025-06-27 under the SGS Listed Mark, naming STEEL 6, STEEL 9 and STEEL 11 (and the Drop, Hive and CLIFF heaters) to UL 60335-1, CAN/CSA C22.2 No. 60335-1 and CAN/CSA E60335-2-53. The certificate’s conditions say the heaters have no controls of their own, were evaluated with the UKU controller, must be used with sauna stones, and that CLIFF and STEEL models must be anchored. UL 875, the standard on Harvia’s and Nootka’s listings, is not among the standards. The PDF copy we also read is hosted by a retailer and shows an effective date of 2022-09-02. Open ↗ (opens in a new tab)

Who paid, and why it matters

Independent The tester took no money from the maker for it: a consumer group, a journalist, a university or a regulator.
Paid certification An outside lab or certifier tested or listed it, and the maker paid for that.
Maker’s own test A lab report or certificate of analysis the maker commissioned and published.

A certification is a floor, not a verdict: it checks what its program checks and nothing else. We weigh tests by someone with no stake in the result most.

What people ask Worries raised online and elsewhere, and what we found 6 questions

Is it certified for North America?: Yes, and we could check it. SGS North America’s own certificate page (opens in a new tab), which the QR code on the certificate PDF (opens in a new tab) points to, lists the STEEL 6 (240 V, 6 kW) to UL 60335-1 and CSA E60335-2-53 as valid, and OSHA’s list (opens in a new tab) of nationally recognized testing laboratories names SGS North America with UL 60335-1 in its scope. The record’s conditions say the heater has no controls of its own and was evaluated with the UKU control. HUUM’s US certificates page (opens in a new tab) shows an SGS Listed logo with no certificate number, its EU page (opens in a new tab) shows none, and the US manual (opens in a new tab) says the safety of the product is based on EN 60335-2-53. The standards on the record do not include UL 875, the one on Harvia’s and Nootka’s listings, so ask your electrician and inspector what your area accepts.
Do the elements fail early, and does the warranty cover them?: HUUM’s warranty terms (opens in a new tab) give 3 years for electrical heaters in private use but exclude heating elements, sauna stones and all sensors. Dealers sell replacement elements: Sauna Place (opens in a new tab) lists a 2,000 W stainless one for $205, and we did not confirm how many a 6 kW STEEL uses. We could not find how often they fail. On Trustpilot (opens in a new tab) HUUM has 17 reviews and 1.9 stars out of 5, 82% of them one star (read 2026-11-03). Five mention elements. Four are complaints: failure after three months and not covered (HUUM replied that elements are not in the warranty), elements “lighting on fire” during heat-up (HUUM replied it had no record of it), faulty elements not covered, and a new Drop 9 kW whose elements an electrician found wired wrongly. One, at five stars, says its elements are still in good shape. None names the STEEL, and the sample is small and self-selected.
Who handles the warranty in the US?: HUUM’s terms cover new products sold by HUUM or its authorized dealers and say a claim goes through the dealer. Finnish Sauna Builders, a dealer, says on its package page that it can no longer handle HUUM parts or warranty claims, which go to HUUM in Estonia (support@huum.eu), yet lists a 5-year warranty on the same page. SaunaHeaters.com gives the 3-year term. Ask your seller who services it before you buy.
Why does the manual say to have a specialist lay the stones?: The manual (opens in a new tab) says stones must be stacked sparsely between the heating elements, because stones packed too close can overheat the elements, and also warns that a stone container filled too sparsely is a fire hazard. It recommends a specialist do it. The STEEL also holds about 330 lb, so plan for the weight on the floor and for 10 boxes of stones.
Does it need a control, and does the Wi-Fi version collect data?: It cannot run without a HUUM UKU control, which comes in a local version or a Wi-Fi version that connects through the HUUM app. The Wi-Fi package costs about $260 more at SaunaHeaters.com. We did not review what the app collects.
Does it need a safety railing or a GFCI breaker?: HUUM strongly recommends a safety railing around it, either your builder’s or its own, and the Finnish Sauna Builders package includes one. The manual recommends connecting it without a GFCI breaker and says the power cable must be heat-resistant (not PVC) and rated UL 62 in the US. Ask your electrician and inspector what your code requires.

Why we chose it What put it on our list 5 points

It holds the most stone of any heater we list, about 330 lb, with the elements in direct contact with the stones, which is how a sauna heater makes soft, long-lasting steam. A Harvia Cilindro takes 200 lb and a Spirit 110 lb.
Its safety listing can be checked: SGS North America’s own certificate page shows the STEEL 6 valid, and OSHA lists SGS North America as a recognized testing laboratory for UL 60335-1.
Materials are plain: a stainless steel enclosure and stainless elements, made in Estonia, with clearances as small as 2 in per the manual’s table and 47.3 in to the ceiling, for tight rooms.
The maker publishes its US manual and its warranty terms, and three US stores list the heater alone at the same $2,033.
Replaceable parts exist: dealers sell the stainless elements as spare parts.

Trade-offs What to weigh before you buy 6 points

Its safety listing is an SGS certificate to UL 60335-1 and CSA E60335-2-53, not the UL 875 on Harvia and Nootka heaters, it was evaluated with the HUUM UKU control, and HUUM’s manual cites only the European standard.
Heating elements, stones and sensors are outside the 3-year warranty, one US dealer says it can no longer handle HUUM claims, and HUUM’s Trustpilot page (17 reviews, 1.9 of 5) has complaints about elements and refused claims, none naming the STEEL.
The heater alone is $2,033 but cannot run without a UKU control and about 330 lb of stones, which add about $1,860 at SaunaHeaters.com, so a working set is nearer $3,900.
A tall hot tower with 330 lb of stones needs a safety railing and a floor that can take the weight.
Fit the stones carefully: too tight overheats the elements and too loose is a fire hazard, per the manual.
Ask a doctor first if you have heart disease or are pregnant, and skip alcohol (see our hot baths page).

What to know Details worth knowing first

The STEEL is a slim stainless steel tower that holds far more stone than any other heater we list, about 330 lb, with the stones in direct contact with the elements. That mass is what gives the soft, long-lasting steam a traditional sauna is about, and it fits rooms of 177 to 318 ft³ with clearances as small as 2 in.

It is not a plug-in purchase. The heater alone is $2,033, it needs a UKU control and about ten boxes of stones, and a working set runs near $3,900. HUUM’s manual wants the stones laid by someone who knows how, because the spacing matters for the elements.

The open questions are about service. SGS’s own database confirms the safety certificate, which is to UL 60335-1 and CSA E60335-2-53 rather than UL 875. The warranty leaves out the heating elements, one US dealer says it can no longer handle HUUM claims, and HUUM’s Trustpilot page has complaints about elements and claims, though none names the STEEL. Ask who services it, and ask a doctor first if you have a heart condition or are pregnant.

What we checked Each claim, and how sure we are of it 5 checks

Third-party tested: Yes
Tested by: SGS North America (certificate to UL 60335-1 and CSA E60335-2-53)

How HUUM STEEL 6 kW Electric Sauna Heater (240 V) measures up against our sauna heaters criteria
What we checked	What we found
Stones and steam Maker’s claim	Holds about 330 lb (150 kg) of 3 to 5 cm stones, stacked sparsely between the elements, for rooms of 177 to 318 ft³, per HUUM’s US manual. We have no measured temperatures.
Safety listing Verified	SGS North America’s own certificate page lists the STEEL 6 to UL 60335-1 and CSA E60335-2-53 as valid (issued 2025-06-27 to HUUM Sauna OÜ), evaluated with the UKU control. OSHA lists SGS North America as a recognized testing laboratory. The standards do not include UL 875, and HUUM’s manual cites only EN 60335-2-53.
Stainless steel or cast iron body Maker’s claim	HUUM names a stainless steel enclosure, and a dealer says the elements are stainless too. The manual does not state a grade.
Wiring and clearances Maker’s claim	240 V, 25 A load, 30 A breaker and 10 AWG heat-resistant cable for the 6 kW; anchored to the floor with the brackets; clearances in Table 3 of the manual.
Recalls and notices Verified	Searches on 2026-11-03 of the US Consumer Product Safety Commission recalls (titles and sauna products), the Government of Canada recalls site and California’s Prop 65 notices found nothing naming HUUM.

What the labels mean

Verified We opened an independent record that confirms it: a certifier’s listing, a regulator’s list or a lab report. It is linked under Sources.
Maker’s claim The maker says so on its own page or label. We read it but found no independent record.
Not verified We looked and could not confirm it, or the maker does not say. Treat it as unknown.

Sources Where our facts come from 18 sources

HUUM STEEL electric sauna heater: maker’s US product page. Maker’s page. Stainless steel enclosure, 330 lb of stones, made in Estonia, UKU control needed, safety railing advice, seen 2026-11-03. Open ↗ (opens in a new tab)
HUUM STEEL installation and operation manual, US edition (PDF). Maker’s page. Rooms, amps, breaker and wire sizes, clearances, stone fitting, GFCI advice, EN 60335-2-53. Open ↗ (opens in a new tab)
HUUM limited warranty terms (PDF). Maker’s page. 3 years private use; elements, stones and sensors excluded; authorized dealers only. Open ↗ (opens in a new tab)
HUUM certificates page (EU site). Maker’s page. Shows CE, SZU, ISO 9001 and BimSchV II; no UL, CSA or SGS certificate. Open ↗ (opens in a new tab)
HUUM certificates page (US site). Maker’s page. Adds an SGS Listed logo with no certificate number or link. Open ↗ (opens in a new tab)
SGS North America certificate page for SGSNA/20/SUW/00067X. Certifier or regulator listing. SGS’s own record, reached through the QR code on the certificate: STEEL 6 to UL 60335-1 and CSA E60335-2-53, status valid, issued 2025-06-27, read 2026-11-03. Open ↗ (opens in a new tab)
SGS North America certificate of compliance SGSNA/20/SUW/00067X (PDF, hosted by a retailer). Certifier or regulator listing. Lists STEEL 6, 9 and 11 to UL 60335-1 and CSA E60335-2-53, effective 2022-09-02; conditions of acceptability on page 2. Open ↗ (opens in a new tab)
OSHA: SGS North America, Inc. as a nationally recognized testing laboratory. Certifier or regulator listing. Lists UL 60335-1 among its recognized standards, at the Suwanee, Georgia address on the certificate. Open ↗ (opens in a new tab)
SaunaHeaters.com: HUUM STEEL 6 kW package. Independent source. $3,895 with UKU local control and 330 lb of stones, read 2026-11-03. Open ↗ (opens in a new tab)
SaunaHeaters.com: HUUM STEEL 6 kW heater. Independent source. $2,033 for the heater alone; stainless steel elements; 3-year residential warranty excluding elements. Open ↗ (opens in a new tab)
Sauna Place: HUUM STEEL 6 kW. Independent source. $2,033, in stock, control and stones sold separately. Open ↗ (opens in a new tab)
Sauna Place: HUUM SLIM-EL20 2,000 W replacement element. Independent source. $205 for a stainless steel replacement element for CLIFF and STEEL heaters. Open ↗ (opens in a new tab)
My Sauna World: HUUM Steel 6 kW. Independent source. $2,033 for the heater alone, read 2026-11-03. Open ↗ (opens in a new tab)
Finnish Sauna Builders: HUUM STEEL 6.0 kW Ultimate Package. Independent source. $4,566 package; the dealer’s notice about HUUM parts and warranty claims. Open ↗ (opens in a new tab)
Trustpilot: HUUM (huum.eu). Independent source. 17 reviews, 1.9 of 5, 82% one star on 2026-11-03; reviews on elements and claims, none naming the STEEL. Open ↗ (opens in a new tab)
US Consumer Product Safety Commission: recalls with “sauna” in the title. Certifier or regulator listing. No HUUM recall on 2026-11-03. Open ↗ (opens in a new tab)
Government of Canada: recalls and safety alerts, search for sauna. Certifier or regulator listing. Sauna recalls on 2026-11-03 name Tylö, Finnleo and other brands, DIY heater kits and ozone saunas, not HUUM. Open ↗ (opens in a new tab)
California Attorney General: Prop 65 60-day notice search. Certifier or regulator listing. No notice names HUUM (searched 2026-11-03). Open ↗ (opens in a new tab)

Alternatives Other options to compare 3 options

HUUM DROP 6 kW The same maker’s wall-mounted heater, with about 121 lb of stones. About $3,441 as a package.
Harvia Cilindro PC90 Floor-standing, 200 lb of stones, built-in dials and a UL 875 listing we could match. About $1,920 with stones.
Nootka Saunas Electric Heater A 9 kW wall heater listed to UL 875 and CSA C22.2 No. 164 in Intertek’s directory, about $2,100 with its control, but a small rock load.

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