Backyard Sauna Pro

HUUM Sauna Heater Review (2025)

Updated February 2025 — Backyard Sauna Pro

Modern sauna interior with bench and stones
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HUUM has built a following among sauna enthusiasts who care about aesthetics. Their Drop and Hive heaters look unlike anything else on the market, organic, sculptural, and unmistakably European. The stone capacity is generous and the WiFi control integration is genuinely useful.

There's also a real issue US buyers need to know about. Here's the full picture.

Quick Verdict

  • Best for: European buyers or US buyers in jurisdictions where UL listing isn't required
  • Aesthetics: Some of the best-looking heaters available
  • Made in: Estonia
  • Watch out for: UL certification questions affect insurance and code compliance in some US areas
  • US alternative: Harvia KIP or Harvia Cilindro for comparable performance with clear UL listing

What HUUM Does Well

Stone capacity

HUUM's design philosophy prioritizes stone mass. The Drop 4.5kW holds around 22 lbs of stones; the Hive 9kW holds about 50 lbs. More stone mass means better heat storage, more even steam distribution, and a softer löyly (steam) than heaters with smaller stone loads. This is a real performance advantage for serious sauna users.

UKU WiFi control

HUUM's optional UKU controller lets you preheat the sauna remotely via app. For an outdoor sauna that takes 45-60 minutes to heat, being able to start it from your phone before you leave the house is genuinely useful. The app is well-reviewed and the integration works reliably.

Aesthetics

The Drop looks like a stone hanging in mid-air. The Hive has an architectural quality that most other heaters lack. If the sauna interior matters to you visually, HUUM heaters are in a different category than the utilitarian look of most competitors.

The UL Listing Concern

This is the thing US buyers need to research before purchasing. HUUM has marketed some products as UL listed in the US market when the certification applied to components rather than the complete assembled unit, a meaningful distinction in building code compliance and homeowner insurance contexts.

The practical implications vary. In some US jurisdictions, an electrical inspector may require the heater to carry full UL listing for the complete unit. Some homeowner insurance policies have similar requirements. In others it's a non-issue.

Before buying a HUUM heater for installation in the US, confirm with your local building department and your insurance provider what they require. If either requires full UL listing on the complete unit, Harvia is the straightforward alternative, clear UL listing, similar performance range, and widely stocked in North America.

HUUM vs Harvia

Factor HUUM Harvia
Aesthetics Excellent Functional/standard
Stone capacity High Good
UL listing (US) Verify before buying Clear
US availability Limited Wide
WiFi control Yes (UKU) Some models
Price Premium Mid-range

Best HUUM Models

HUUM Hive 13kW

The larger wood-look heater with substantial stone capacity. Designed for bigger rooms of 400-700 cubic feet. The aesthetic is distinctive and the steam quality is excellent when properly loaded with olivine stones.

Check Price on Amazon

FAQ

Is HUUM a good sauna heater brand?

Good design and stone capacity. US buyers should verify UL certification requirements with their local building department and insurer before purchasing.

Where are HUUM heaters made?

Estonia. Strong reputation in European markets.

HUUM vs Harvia, which is better for US buyers?

Harvia for ease of compliance and availability. HUUM if aesthetics and stone capacity are the priority and UL listing isn't a concern in your jurisdiction.