The HUUM DROP 4STU Package is the complete ready-to-operate bundle for the 4.5kW DROP electric sauna heater - including the heater, UKU Local controller, and 132 lbs of sauna stones (4 boxes, 5-10 cm rounded olivine). No UKU Extension Box is required at 4.5kW. The DROP is a fundamentally different heater from the STEEL and CLIFF series: where those heaters are floor-standing pillars, the DROP is a wall-mounted sculptural unit inspired by the silhouette of a falling water drop - a rounded, organic form that HUUM describes as softening and complementing the angular interior of a classic sauna, giving it a touch of elegance. The DROP is the most visually distinctive heater in the HUUM lineup and the winner of the Red Dot Design Award for product design. At 4.5kW and 132 lbs of stones for rooms from 106 to 247 adjusted cubic feet, the DROP 4STU Package covers the small to medium home sauna range. Stones are 5-10 cm rounded olivine - a different size from the 3-5 cm stones used in the CLIFF and STEEL series. The wall bracket mounts with the bottom of the bracket 12.2" above the hard floor. Minimum wall thickness for structural mounting is 3.94" (100mm). 240V/1PH, 30A, 10AWG. Max 230°F. SGS certified. 5-year limited warranty (excluding elements). Designed and made in Estonia by HUUM.
DROP - a water drop, not a pillar - wall-mounted sculptural focal point
The HUUM DROP's design starts from a different premise than every other HUUM heater. Where the STEEL and CLIFF are floor-standing vertical pillars with stacked stone columns, the DROP is a wall-mounted rounded unit shaped after a single falling drop of water. HUUM's own description of the design intent: the DROP sauna heater is inspired by the purest element in nature - a drop of water. Its rounded design softens and complements the angular interior of a classic sauna, giving it a touch of elegance. The organic form is architectural as much as it is functional - a heater designed to be looked at and to become the focal point of the sauna room, not a utilitarian appliance tucked into a corner. HUUM's own website describes the DROP as the eye-catching focal point of each steam room. The Red Dot Design Award confirms this recognition: the DROP won for masterful craftsmanship and unique aesthetic - HUUM's third Red Dot award across their lineup, alongside the CLIFF and the earlier HIVE series awards.
132 lbs of stones - more than most wood-burning stoves
HUUM's own description of the DROP's stone capacity puts it in direct context: this compact wall-mounted heater can fit up to 132 lbs of stones, exceeding most wood-burning stoves and guaranteeing long-lasting steam. At 132 lbs (4 boxes, 5-10 cm rounded olivine) in a 15.4"W x 13.2"D x 23.3"H wall-mounted unit, the DROP holds significantly more stone mass than the typical wall-mounted electric heater in the same output class. The stones are kept fully exposed in the heater - by keeping the stones exposed, the heater achieves better airflow to create gentler steam and optimal heat stability. The 5-10 cm stone size is larger than the 3-5 cm rounded olivine used in the CLIFF and STEEL series - this is a DROP-specific requirement and the two stone sizes are not interchangeable between heater series. A Stone Placement Video document is available to guide correct stone loading in the DROP's unique rounded stone basket.
Package contents and installation notes
The DROP 4STU Package (SKU 534-BDL-DROP45STULB) includes the DROP 4.5kW heater, UKU Local controller, and 132 lbs stones (4 boxes). No UKU Extension Box is required at 4.5kW - the Extension Box threshold begins at heaters over 9kW. The heater includes a heat diverter and heating element retainer as standard. The wall bracket positions the bottom of the heater 12.2" above the hard floor. The minimum wall thickness for structural mounting is 3.94" (100mm) - HUUM's installation guidance is explicit: do not mount the DROP to cedar paneling alone; anchor to wall framing. When embedding the DROP into a sauna bench using the optional Flange D (sold separately), at least 14.8" of the heater must protrude above the bench surface. The optional DROP Drip Tray (sold separately) catches excess water that runs off the stones and prevents pooling on the floor. The optional DROP safety railing (sold separately) adds a protective barrier around the heater's hot stone surface.
4.5kW wall-mounted electric sauna heater package for rooms from 106 to 247 adjusted cubic feet. DROP 4STU Pkg - complete package: DROP 4.5kW heater, UKU Local controller, and 132 lbs stones (4 boxes, 5-10 cm rounded olivine). No UKU Extension Box required. Water drop silhouette design - Red Dot Design Award winner. 132 lbs stones - more than most wood-burning stoves. Stones fully exposed - better airflow, gentler steam. Wall-mounted: bracket bottom 12.2" above hard floor. Min wall thickness 3.94" for structural mounting. Heat diverter and heating element retainer included. Stones are 5-10 cm (not 3-5 cm - DROP-specific). 15.4"W x 13.2"D x 23.3"H - 24 lbs. Max 230°F. 240V/1PH - 30A - 10AWG. Optional: DROP safety railing, Flange D bench embedding, Drip Tray. SGS certified. 5-year limited warranty (excl. elements). Designed and made in Estonia by HUUM.
4.5 kW 106 to 247 cu ft (adjusted) Package - DROP heater, UKU Local controller, and 132 lbs stones No UKU Extension Box required Water drop silhouette - Red Dot Design Award winner 132 lbs stones included (4 boxes, 5-10 cm rounded olivine) Stones fully exposed - better airflow and gentler steam More stone capacity than most wood-burning stoves Wall-mounted - bracket bottom 12.2" above hard floor Min wall thickness 3.94" - anchor to framing required Heat diverter and element retainer included Stones are 5-10 cm - not 3-5 cm 15.4"W x 13.2"D x 23.3"H - 24 lbs Max 230°F 240V/1PH - 30A - 10AWG SGS certified 5-year limited warranty (excl. elements) Designed and made in Estonia by HUUM
Specifications
Package contents
| Heater |
HUUM DROP 4.5kW wall-mounted electric sauna heater |
| Controller (included) |
UKU Local controller |
| Extension Box |
Not required for 4.5kW - not included |
| Stones (included) |
132 lbs / 60 kg (4 boxes, 5-10 cm rounded olivine) |
| Heat diverter |
Included |
| Heating element retainer |
Included |
| Wall mounting bracket |
Included |
Performance
| Power output |
4.5 kW |
| Fuel type |
Electric (240V/1PH) |
| Room volume |
106 to 247 cu ft (adjusted) / 3-7 m3 |
| Max temperature |
230°F (110°C) |
| Stone capacity |
132 lbs / 60 kg (4 boxes, 5-10 cm rounded olivine) - included |
| Stone size |
5-10 cm / 2-4 in (rounded olivine - DROP-specific) |
| Stone exposure |
Fully exposed - better airflow for gentler steam |
DROP design and awards
| Design inspiration |
A falling drop of water - organic rounded form |
| Design award |
Red Dot Design Award winner |
| Stone capacity vs wood stoves |
132 lbs - exceeds most wood-burning stoves |
| Stone placement guide |
Stone Placement Video available (see documents) |
| Interior effect |
Softens angular sauna interior - eye-catching focal point |
Physical dimensions and mounting
| Width |
15.4 in (390 mm) |
| Depth |
13.2 in (335 mm) |
| Height |
23.3 in (590 mm) |
| Heater weight |
24 lbs (11 kg) |
| Bracket mounting height |
Bottom of bracket 12.2" above hard floor |
| Min wall thickness |
3.94 in (100 mm) - must anchor to framing |
| Bench embed protrusion |
Min 14.8" above bench surface when embedded |
Electrical
| Voltage / phase |
240VAC, 1-phase, 60Hz |
| Amperage |
18.8A |
| Circuit breaker |
30A dedicated circuit |
| Wire size |
10AWG |
| UKU Extension Box |
Not required for 4.5kW |
| Certification |
SGS certified |
UKU Local controller (included)
| Controller type |
UKU Local - physical wall panel |
| Remote / app control |
Not available with UKU Local |
| Safety features |
Door sensor, overheating protection, child safety lock |
| Integration |
Compatible with lights, ventilation, steamer |
| Upgrade option |
UKU Wi-Fi controller available separately |
Certifications, warranty, and DROP-specific accessories
| Certifications |
SGS certified |
| Origin |
Designed and made in Estonia by HUUM |
| Warranty |
5-year limited (excluding elements) |
| Safety railing |
DROP safety railing (DROP-specific) - sold separately |
| Bench embedding |
Flange D (DROP-specific) - sold separately |
| Water management |
DROP Drip Tray - sold separately |
What's included
HUUM DROP 4.5kW wall-mounted electric sauna heater
UKU Local controller (physical wall panel)
132 lbs sauna stones (4 boxes, 5-10 cm rounded olivine)
Heat diverter
Heating element retainer
Wall mounting bracket
DROP Installation and Operation Manual
UKU Installation and Operation Manual
5-year limited warranty (excluding elements)
Required (not included): Licensed electrician for wiring (240V/1PH, 30A dedicated circuit, 10AWG wire). Must anchor to wall framing - min 3.94" wall thickness. Optional accessories (sold separately - DROP-specific): DROP safety railing; Flange D bench embedding flange; DROP Drip Tray. To upgrade to Wi-Fi and app control, the UKU Wi-Fi controller is available separately.
Why the HUUM DROP 4STU Package stands out
Complete package - heater, controller, and stones in one order
The DROP 4STU Package includes the DROP 4.5kW heater, UKU Local controller, and 132 lbs of 5-10 cm rounded olivine stones (4 boxes) together. The DROP requires a UKU controller for all operation - the heater has no built-in controls. Purchasing the heater alone requires separately sourcing both the controller and the correct DROP-specific stones. This package assembles all three items in one order, ensures the correct stone size (5-10 cm, not the 3-5 cm used in CLIFF and STEEL), and includes the Stone Placement Video as a document to guide correct loading in the DROP's unique rounded stone basket. No UKU Extension Box is required at 4.5kW.
Red Dot Award - water drop design in a sauna room
The DROP won the Red Dot Design Award for product design - recognition of the combination of sculptural water-drop silhouette, brushed stainless steel finish, and the fully exposed stone basket that puts the 132-lb stone column at the visual centre of the heater. HUUM's description of the design effect is direct: the organic and minimalist design ensures it is the eye-catching focal point of each steam room. The rounded form visually softens the straight wooden lines of a traditional sauna interior in a way that a rectangular or pillar-format heater does not. For buyers who want their sauna heater to be architecturally considered as well as functionally excellent, the DROP is HUUM's purpose-built answer.
132 lbs of stones - exceeds most wood-burning stoves
HUUM's own marketing of the DROP's stone capacity places it in direct comparison with wood-burning stoves rather than other electric heaters: this compact wall-mounted heater can fit up to 132 lbs of stones, exceeding most wood-burning stoves. For an electric wall-mounted heater at 4.5kW, 132 lbs of stone mass is exceptional. The stones are fully exposed in the rounded basket - by keeping the stones exposed, the heater achieves better airflow to create gentler steam and optimal heat stability. The large stone thermal mass produces consistent, long-lasting steam and holds heat well after the heating elements cycle off - the same stone-primary performance principle that HUUM applies across their entire lineup.
5-10 cm stones - DROP-specific - not 3-5 cm
The DROP uses 5-10 cm (2-4 in) rounded olivine stones - a different size from the 3-5 cm stones used in the CLIFF and STEEL series. This is not interchangeable: the DROP's stone basket geometry is designed for 5-10 cm stones, and using 3-5 cm stones would result in poor fit and uneven heat distribution. The 4 boxes of 5-10 cm rounded olivine included in the package are the correct DROP specification - no additional stone sourcing or size verification is needed. A Stone Placement Video is available in the documents section to guide correct arrangement of the stones in the DROP's unique rounded basket shape.
Wall-mounted - saves sauna floor space
The DROP's wall-mounted installation frees up sauna floor space that a floor-standing heater would occupy. At 24 lbs without stones, the DROP is the lightest heater in the HUUM lineup - significantly easier to handle during installation than the floor-standing STEEL or CLIFF models. The wall bracket positions the bottom of the heater 12.2" above the hard floor. Anchoring to wall framing is required - minimum wall thickness is 3.94" (100mm) and the heater must not be mounted to cedar paneling alone. The optional Flange D (sold separately) allows the DROP to be embedded into a sauna bench platform with at least 14.8" of the heater protruding above the bench surface.
DROP Series - 4.5kW, 6kW, 7.5kW, and 9kW configurations
The 534-BDL-DROP45STULB is the 4.5kW package configuration of the DROP Series. The DROP platform covers four output levels: DROP 4.5 (4.5kW, 106-247 cu ft, 30A/10AWG, no Extension Box), DROP 6 (6kW, 30A/10AWG, no Extension Box), DROP 7.5 (7.5kW, 40A/8AWG, no Extension Box), and DROP 9 (9kW, 40A/8AWG, no Extension Box). All four share the same water-drop silhouette, Red Dot Award winning design, fully exposed stone basket, 5-10 cm stone specification, DROP-specific accessories (Flange D, Drip Tray, safety railing), SGS certification, and 5-year limited warranty. UKU Extension Box is not required for any DROP model (all are 9kW or below). Designed and made in Estonia by HUUM. We are an authorized HUUM dealer.
About HUUM
Designed in Estonia - SGS Certified - DROP Series - Red Dot Award - Complete Package
HUUM DROP 4STU Package. 4.5kW. 106-247 cu ft. Heater, UKU Local, 132 lbs stones. Red Dot winner.
HUUM is an Estonian sauna heater company. The DROP 4STU Package is the complete ready-to-operate bundle for the Red Dot Award-winning DROP 4.5kW wall-mounted sauna heater - water drop silhouette, 132 lbs of fully exposed 5-10 cm stones (4 boxes), UKU Local controller, and heat diverter all included. No UKU Extension Box required. A licensed electrician is the only remaining requirement. We are an authorized HUUM dealer.
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4.5kW electric - 106-247 cu ft - DROP water-drop wall-mounted design
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Red Dot Design Award winner - sauna room focal point
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UKU Local controller included - no Extension Box required
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132 lbs stones included (4 boxes, 5-10 cm) - exceeds most wood stoves
- SGS certified - 5-year warranty (excl. elements) - made in Estonia
DROP 4STU Pkg vs STEEL Mini 4 vs CLIFF 6 vs DROP 6 - HUUM electric heater guide
DROP 4STU Pkg vs STEEL Mini 4 vs CLIFF 6 vs DROP 6 - choosing the right HUUM electric heater
Four HUUM electric options serve different room sizes, aesthetics, and mounting preferences. STEEL Mini 4 H1007012: 3.5kW, 106-177 cu ft (adjusted), wall-mounted, 12.6"W x 6"D vertical pillar, 132 lbs stones (3-5 cm), 15A/14AWG. Right for the smallest rooms where a slim vertical wall-mount and 3.5kW are the specification. DROP 4STU Pkg 534-BDL-DROP45STULB (this listing): 4.5kW, 106-247 cu ft (adjusted), wall-mounted, 15.4"W x 13.2"D x 23.3"H rounded water-drop form, 132 lbs stones (5-10 cm), UKU Local + stones included, 30A/10AWG, Red Dot Award winner. Right for the 106-247 cu ft range where a distinctive sculptural wall-mount and a complete ready-to-operate package are the priorities. CLIFF 6 H1004012: 6kW, 176-353 cu ft, floor-standing, open recycled-steel cage, 165 lbs stones (3-5 cm), 2.36" side clearances, 30A/10AWG. Right when floor-standing, 6kW, and the CLIFF's open-cage design are the specification. DROP 6 (package or heater): same DROP water-drop form at 6kW for a slightly larger room range than the DROP 4.5. Right when the DROP design is the priority but 6kW output is needed over 4.5kW.
Manuals and Documents
Warranty
5-year limited warranty (excluding elements)
The HUUM DROP 4.5kW carries HUUM's 5-year limited warranty from the date of purchase. The warranty covers defects in manufacturing and materials under normal use and maintenance conditions. Heating elements are excluded from the 5-year term and carry a separate warranty period per the warranty document. The warranty does not cover damage caused by improper installation, failure to follow the installation and operation manual, mounting to a wall without adequate structural support (minimum wall thickness 3.94" / 100mm, must anchor to framing), use of incorrect stone type or size (must use 5-10 cm rounded olivine; decorative stones must not be used), or operating without the required stone load. The UKU Local controller included in the package carries its own separate HUUM warranty terms. Proof of purchase from an authorized HUUM dealer is required for warranty claims. We are an authorized HUUM dealer.
