The HUUM DROP 4.5STU Package is a complete sauna heater package for rooms from 106 to 248 cubic feet, including the award-winning DROP 4.5kW wall-mounted heater, UKU sauna control (Local or WiFi - selected at checkout), and 122 lbs of rounded olivine diabase sauna stones. Everything needed to operate the heater arrives together - no separate stone or control purchase required. The DROP 4.5kW is HUUM's entry in the DROP series: the same water-droplet-inspired stainless steel body and 122-lb stone capacity as all DROP models, at 4.5kW for the 106-248 cu ft room range on a standard 240V/1-phase, 30A circuit.
The DROP design - water drop form, Red Dot Award winner, 122 lbs of stone
The HUUM DROP sauna heater is designed in the shape of a water droplet - a rounded, organic form that softens the angular lines of a traditional sauna interior and makes the heater itself a design feature of the room. Winner of the prestigious Red Dot Award for product design, the DROP combines sculptural aesthetics with a specific and deliberate engineering outcome: an exceptionally large stone capacity relative to its compact wall-mounted form. At 122 lbs (55 kg) of rounded olivine diabase stones, the DROP holds more stone mass than most conventional wood-burning stoves. More stone mass means more thermal capacity - the stones store more heat during the warm-up cycle, release it more slowly and evenly during the session, and produce softer, longer-lasting steam when water is ladled over them. The result is a more consistent bathing temperature, milder steam character, and a longer effective session before the stones lose heat.
Why stone mass matters - and why HUUM rounds it differently
The character of loyly steam - its softness, duration, and intensity - is directly related to the stone mass carrying the heat. A heater with a small stone load produces sharp, quick steam that dissipates rapidly; a heater with a large stone load produces a gentler, longer wave of steam that spreads through the room rather than concentrating at the ladle point. The DROP's 122-lb capacity is the characteristic that makes it perform above its output class. HUUM also specifies rounded olivine stones specifically for the DROP - the rounded form allows denser packing within the basket, better water flow between stones when ladling, and milder steam production compared to angular crushed stones. The 4 boxes of rounded olivine diabase included in this package are the correct specification for the DROP 4.5.
UKU control - Local or WiFi, selected at checkout
The package includes the UKU Local Black control as standard, with UKU WiFi available as an upgrade at checkout. The UKU Local Black is a digital sauna control that mounts on the sauna wall or changing room wall, operates the heater on/off and temperature, and provides timer and safety functions from the panel buttons. The UKU WiFi version adds HUUM app connectivity for iOS and Android - remote preheat from anywhere, session scheduling, and temperature monitoring from a phone before arriving at the sauna. Both UKU variants are compatible with the DROP 4.5kW without any additional extension box (the UKU Extension Box is only required for heaters over 11kW). The UKU control is mounted outside the sauna room or at the correct safety distance from the heater if inside.
Complete 4.5kW wall-mounted sauna heater package for rooms from 106 to 248 cubic feet. Includes DROP 4.5kW heater, UKU control (Local Black or WiFi - select at checkout), and 122 lbs of rounded olivine diabase stones (4 boxes). Red Dot Award-winning water-droplet design. 122 lbs stone capacity - more than most wood-burning stoves - for soft, consistent, long-lasting steam. Direct stone-to-element contact for even heat. Stainless steel construction. 240V / 1-phase. 30A breaker, 10 AWG wire. Max 230°F. 2" safety clearance all sides. SGS Listed. 5-year warranty (elements excluded). Made in Estonia by HUUM.
Complete package - control + 122 lbs stones included 4.5 kW 106 to 248 cu ft Red Dot Award-winning design Water-droplet inspired form 122 lb stone capacity - 4 boxes olivine included More stone mass than most wood-burning stoves Soft consistent steam - rounded olivine diabase UKU Local Black or UKU WiFi - select at checkout HUUM app - iOS and Android (WiFi variant) 240V / 1-phase - 30A breaker - 10 AWG Stainless steel - made in Estonia SGS Listed 5-year warranty (elements excluded)
Specifications
Electrical
| Power output |
4.5 kW |
| Voltage |
240V / 1-phase / 60 Hz |
| Amperage draw |
18.75 A |
| Circuit breaker required |
30 A (standard 2-pole - no GFI/GFCI) |
| Wire gauge |
10 AWG |
| Certification |
SGS Listed |
Room sizing and stones
| Room volume |
106 to 248 cu ft |
| Stone capacity |
122 lbs (55 kg) |
| Stones included |
Yes - 4 boxes rounded olivine diabase |
| Stone size |
2" to 4" (5-10 cm) rounded |
| Max temperature |
230°F (110°C) |
Physical
| Dimensions (W x D x H) |
15.4" x 13.2" x 23.3" (390 x 335 x 590 mm) |
| Heater weight |
24 lbs |
| Construction |
Stainless steel |
| Mounting |
Wall-mounted |
| Safety clearance |
2" all sides |
| Origin |
Made in Estonia by HUUM |
Control options - select at checkout
| UKU Local Black |
Wall-mounted digital control - on-site operation |
| UKU WiFi |
Adds HUUM app remote preheat and scheduling |
| App |
HUUM app - iOS and Android (WiFi variant) |
| UKU Extension Box required |
No - only needed for heaters over 11kW |
DROP series stone advantage
| Stone capacity |
122 lbs - more than most wood-burning stoves |
| Stone type |
Rounded olivine diabase - 2"-4" (5-10 cm) |
| Steam character |
Soft, consistent, long-lasting |
| Element contact |
Direct stone-to-element for even heat distribution |
Warranty and awards
| Warranty |
5 years (elements excluded) |
| Design award |
Red Dot Award winner - product design |
| Design inspiration |
Water droplet form |
What's included
HUUM DROP 4.5kW wall-mounted sauna heater - stainless steel
UKU sauna control (Local Black or WiFi - selected at checkout)
Rounded olivine diabase sauna stones - 4 boxes (122 lbs)
Wall mount bracket and hardware
Installation and operation manual
Optional accessories (sold separately): HUUM safety railing (recommended), HUUM Drip Tray, HUUM Flange D (for bench embedding). A licensed electrician is required for all electrical connections.
Why the HUUM DROP 4.5STU Package stands out
122 lbs of stone - more than most wood-burning stoves
The DROP's 122-lb stone capacity is its defining engineering achievement. For a compact wall-mounted electric heater, this stone load is exceptional - most wood-burning stoves carry less. More thermal mass means slower, softer steam release, a more consistent bathing temperature, and longer effective sessions. The DROP's stone-to-element contact ensures direct, even heat transfer throughout the full stone load.
Red Dot Award design - water drop form
Winner of Europe's prestigious Red Dot Award for product design, the DROP's water-droplet shape is not a styling exercise but a structural form that allows the specific rounded basket geometry needed for its large stone capacity. The organic, rounded body softens the angular interior of a traditional sauna room and makes the heater itself the visual centrepiece.
Complete package - nothing missing
DROP 4.5kW heater, UKU control, and 4 boxes of rounded olivine stones all included. No separate stone sourcing, no separate control purchase. The correct stone type and quantity for the DROP 4.5 are pre-specified - rounded olivine diabase at 2"-4" for optimal steam character and stone density within the DROP basket.
Rounded olivine diabase stones - softer steam
HUUM specifies rounded olivine diabase specifically for the DROP. Rounded stones pack more densely, allow better water flow between them when ladling, and produce milder, more consistent steam than angular crushed stones. Olivine diabase is a thermally stable volcanic stone that handles repeated heating and water contact without cracking or spalling. The correct stone is as important as the correct heater for the quality of the sauna experience.
UKU WiFi option - preheat from anywhere
Upgrading to UKU WiFi at checkout adds HUUM app control on iOS and Android. Preheat the sauna on the way home, set a scheduled start for a regular sauna time, and monitor the current temperature from anywhere. For bathers who want the sauna ready the moment they arrive without needing to plan 30-60 minutes in advance, the WiFi option removes that constraint entirely.
30A / 10 AWG - standard residential circuit
The DROP 4.5kW runs on a standard 240V/1-phase, 30A circuit with 10 AWG wire - a common residential specification that does not require a dedicated 40A or higher circuit. For new sauna rooms in homes where the electrical panel has capacity for a 30A double-pole breaker, the DROP 4.5 is the practical choice for the 106-248 cu ft range with no special panel upgrade required.
About HUUM
Made in Estonia - Red Dot Award winner
HUUM DROP. The award-winning water-drop heater that carries more stone mass than most wood-burning stoves.
HUUM is an Estonian sauna heater company founded on a single design principle: that electric sauna heaters should produce the same quality of steam experience as traditional wood-burning stoves, and that they should be beautiful objects in the sauna room. The DROP is the product that defines HUUM - its Red Dot Award-winning form, its 122-lb stone capacity, and its direct element-to-stone contact engineering are all in service of a single goal: soft, even, long-lasting loyly from a wall-mounted electric heater. The DROP 4.5STU Package includes everything needed to install and operate the heater - the DROP 4.5kW, the UKU control, and the correct stones. We are an authorized HUUM dealer.
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Complete package - DROP 4.5kW, UKU control, and 122 lbs rounded olivine stones
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4.5kW, 106-248 cu ft - 240V/1PH, 30A breaker, 10 AWG
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122 lb stone capacity - more than most wood-burning stoves
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Red Dot Award design - water-droplet form, stainless steel
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UKU Local or WiFi at checkout - 5-year warranty (elements excluded)
DROP series - four output levels
DROP 4.5 vs DROP 6 vs DROP 7.5 vs DROP 9 - choosing the right output
The DROP series is available in four output levels. DROP 4.5kW covers 106-248 cu ft on a 30A circuit. DROP 6kW covers 177-318 cu ft on a 30A circuit. DROP 7.5kW covers 248-389 cu ft on a 40A circuit. DROP 9kW covers 318-460 cu ft on a 50A circuit. All four models share the same external body dimensions and 122-lb stone capacity - the physical size of the heater does not change between output levels, only the number of heating elements inside the cage. To select the correct output, calculate the adjusted cubic footage of the sauna room - accounting for cold surfaces such as glass walls, tile floors, and natural stone or masonry panels, which require added output to compensate. Use HUUM's online calculator or contact BathingBrands for sizing guidance.
A licensed electrician is required for all electrical connections. Do not connect to a GFI/GFCI breaker. The UKU Extension Box is not required for the DROP 4.5, 6, 7.5, or 9kW models - it is only needed for HUUM heaters over 11kW. The optional HUUM safety railing is recommended for all DROP installations to prevent contact with the hot heater body.
Manuals and Documents
Warranty
5-year limited warranty (elements excluded)
The HUUM DROP 4.5STU Package is covered by HUUM's 5-year limited warranty from the date of purchase. The warranty covers defects in manufacturing and materials under normal use conditions. Heating elements are excluded from the 5-year coverage and carry their own separate warranty period. The warranty does not cover damage caused by improper installation, use of incorrect or non-approved stones, operating the heater without the required stone load, or failure to follow HUUM's installation and operating guidelines. A licensed electrician is required for all electrical connections. Do not connect to a GFI/GFCI breaker. Proof of purchase from an authorized HUUM dealer is required. We are an authorized HUUM dealer.
