HUUM DROP 2.0: What Changed, What It Fixes, and How to Tell Which Version You Have

Close-up of the HUUM DROP 2.0 sauna heater's stones and steel cage

The HUUM DROP 2.0 is the current generation of HUUM's egg-shaped, wall-mounted electric sauna heater. It keeps the design people love and re-engineers the parts behind the most common complaint about early DROP heaters: heating elements touching each other and failing early. HUUM added stronger support rods, a factory-installed element retainer on every model, bottom spacers on every element, a cooler and better-sealed junction box, heavier internal wiring, a heat-resistant terminal strip, and a heat diverter in every box.

At Sauna Signature Radiant, we sell the full DROP 2.0 range across Canada: the DROP 4.5, DROP 6, DROP 7.5 and DROP 9. (HUUM's manuals call them the DROP 4, 6, 7 and 9.) This guide covers every change, in plain language, and is based on HUUM's North American DROP 2.0 manual and HUUM's own dealer training material.

What's new in the HUUM DROP 2.0 at a glance

Known issue on early DROP heaters What HUUM changed in DROP 2.0
Elements shifting under the weight of the stones and touching each other Two larger, wider-set support rods; a factory-installed retainer on every model; spacer plates at the bottom of every element
Heat reaching the electrical junction box Smaller element openings in the reflector, plus an extra reflector on the DROP 7.5 and 9
Moisture and short-circuit risk at the element ends Heat-resistant silicone gaskets with waterproofing plates; element ends shortened by 5 mm
Crowded wiring and heat at the terminal strip Larger connection box; 14 AWG (2.5 mm²) internal wires with no splices; a terminal strip rated to 302 °F (150 °C)
Excess heat on the wall behind the heater and the ceiling corner A heat diverter included with every DROP model
A heater label that could wear off A laser-etched metal data plate with the batch number
Vague stone-care guidance A clear schedule: inspect at 100 hours, rearrange at 200 hours, replace at 400 hours

Why did some early HUUM DROP heaters burn out elements?

We'd rather be upfront: some owners of early DROP heaters reported elements failing sooner than expected. The cause was mechanical, not electrical. The DROP holds about 121 lb (55 kg) of stones in an open steel cage, with the heating elements standing vertically inside. Over hundreds of heat cycles, stones settle and some crack. When the elements weren't held firmly in place, the stones could push them out of position until two elements touched. A contact point becomes a hot spot, and a hot spot shortens an element's life.

Two things made it worse:

  • Stone dust and grit. Crumbled stones and hard-water scale collected at the bottom of the cage and choked airflow around the lowest part of the elements.
  • Water on bare elements. Where elements showed through gaps in the stones, ladled water hit them directly. HUUM's manual notes that this shortens element life.

HUUM's first response, in 2023, was an upgrade kit for the DROP 7.5 and 9: an element retainer and a heat diverter. DROP 2.0 goes much further. It builds the support into every model at the factory and redesigns the electrical side too.

How DROP 2.0 keeps the heating elements apart

DROP 2.0 holds every element in place in three ways: support rods at the frame, a retainer between the elements, and spacers at the bottom. Each one targets the element-contact problem directly.

1. Larger support rods. HUUM replaced the smaller support rods with two larger ones, set slightly farther apart. They now support the elements from the sides as well, so the elements stay evenly spaced at the top and at the bottom.

2. A factory-installed retainer on every model. It used to be a retrofit for the larger heaters. Now every DROP 2.0 ships with a retainer that sits between the elements and stops them touching, both while you lay the stones and during years of use. There are two designs:

  • DROP 4.5 and DROP 6 (3 elements): a support that stops the elements bending forward under the weight of the stones. HUUM installs it at the factory, and it fits only the new DROP 2.0 frame.
  • DROP 7.5 and DROP 9 (5 elements): a welded steel mesh replaces the earlier sheet-metal support. The mesh holds up better to long-term heat, lets more air through, and stops the elements moving forward.

3. Spacers on every element. Support plates sit at the lower end of the elements so they can't touch at the bottom. They come pre-installed and can be adjusted before the stones go in.

Before first use, check that the supports, retainer and spacers are all present and correctly positioned. HUUM's manual makes this the owner's responsibility.

A cooler, better-sealed junction box and heavier wiring

The second set of changes is on the electrical side. It's less visible, but it's what keeps the connections reliable session after session.

Less heat reaching the junction box. HUUM made the element openings in the heat reflector smaller. On the 5-element DROP 7.5 and DROP 9, it also added an extra reflector (a new set of bottom reflectors) to cut the heat reaching the electrical connection box.

Better waterproofing. Heat-resistant silicone gaskets with waterproofing plates now seal the element entry points. The element ends were also shortened by 5 mm, which removes the risk of a short circuit if an end gets bent.

Electrical upgrades:

  • Larger connection box, with room for heavier supply cables.
  • Heavier internal wires: upgraded from 1.5 mm² (16 AWG) to 2.5 mm² (14 AWG), with every splice removed.
  • Terminal strip moved to the side, leaving more working room for the electrician's connection.
  • Neutral and ground repositioned on the terminal strip to spread load and heat more evenly.
  • A more heat-resistant terminal strip: the Körner OK435, rated to 302 °F (150 °C).
  • Easier cable clamp: a longer screw, with Phillips (cross-head) screws instead of the old hex screw.
  • Crimped connections required: HUUM now requires crimped ferrules on the supply cable ends to prevent loose connections.

A heat diverter in every box

Every DROP 2.0 sold in North America, from the DROP 4.5 up to the DROP 9, comes with a heat diverter. It's a curved stainless steel shield that bolts onto the upper rear edge of the heater's reflector. In HUUM's words, its purpose is "to protect the wall behind the heater and the corner of the ceiling from excessive heat." The diverter used to be an add-on for the larger models, and it's now standard in every box.

How to tell a DROP 2.0 from an older DROP

The quickest check is the logo on the front. Look for these signs:

  • The front logo plate. On DROP 2.0, the HUUM logo is a larger, stamped plate welded to the cage at all four corners. It takes over the job of the central grid rib, which is now shorter. HUUM's manual uses this logo plate to tell the two versions apart.
  • A metal data plate on the cage. DROP 2.0 has a laser-etched metal data plate fixed to the grid, and it includes the batch number. Older units had a sticker on the wall mount.
  • Spacers at the bottom of the elements, plus a retainer between them, even on the DROP 4.5 and DROP 6.
  • A heat diverter in the box with every model.

The version matters when you order replacement parts. Some parts, such as the retainers, bottom reflectors and internal cable sets, differ between the two versions, while others fit both. If you're unsure, send us a photo of the front and the data plate and we'll confirm.

HUUM DROP 2.0 specifications for Canada

In Canada, the DROP 2.0 runs on a 240 V single-phase supply (208 V is also supported, at lower output). Choose a model by the volume of your sauna room. Then add 3.3 ft³ for every square foot of uninsulated brick, tile, concrete or glass wall (1 m³ per m²).

Model Output at 240 V Output at 208 V Room size at 240 V Elements Breaker at 240 V Min. wire
DROP 4.5 4.5 kW 3.4 kW 106–248 ft³ (3–7 m³) 3 30 A 10 AWG
DROP 6 6 kW 4.5 kW 177–318 ft³ (5–9 m³) 3 30 A 10 AWG
DROP 7.5 7.5 kW 5.6 kW 248–389 ft³ (7–11 m³) 5 40 A 8 AWG
DROP 9 9 kW 6.75 kW 283–460 ft³ (8–13 m³) 5 50 A 8 AWG

All models share the same basics:

  • Weight: about 143 lb (65 kg) with stones, so the wall needs solid backing.
  • Stones: about 121 lb (55 kg) of 2–4 in (5–10 cm) natural sauna stones, such as olivine diabase.
  • Ceiling height: 75 in (1,900 mm) minimum; 79–91 in (2,000–2,300 mm) recommended.
  • Bench mounting: the heater can be partly recessed into a bench, as long as at least 14¾ in (375 mm) stands above the bench surface. The DROP Embedding Flange finishes the opening.
  • Wiring: a licensed electrician must make the connection, using a cable that meets CSA 49 (as HUUM's manual specifies).
  • Control: a separate controller is required, such as HUUM's UKU.

Laying and caring for the stones

The stones are part of the heater's design. Laid correctly, they protect the elements, and laid poorly, they shorten their life. DROP 2.0 changes how you lay them, and the method depends on the model:

  • DROP 4.5 and DROP 6 (3 elements): place stones between the elements as well, all the way to the bottom. They help support the elements. Don't force them in or bend an element.
  • DROP 7.5 and DROP 9 (5 elements): don't remove the welded mesh support, and don't place stones beneath the mesh or between the elements. Fill around them.

For every model:

  1. Turn the heater off and wear gloves.
  2. Rinse the stones to remove dust.
  3. Place them one by one, never pour them in. Start with the largest stones at the bottom and sides, and lock them in with smaller ones.
  4. Pack them firmly but leave room for air to move.
  5. Make sure no element is visible between the stones. Exposed elements change the safety clearances and get hit by ladled water.

Use only natural stones sold for sauna heaters, never decorative stones. HUUM's warranty doesn't cover damage caused by unsuitable stones.

HUUM's DROP 2.0 stone-care schedule:

Hours of use What to do
Every 100 hours (or at least once a year) Visual inspection
200 hours Rearrange the stones and replace any that are cracked
400 hours Replace all the stones

For a sauna used three times a week for about an hour, 100 hours comes around every eight months. Stone care is the single biggest thing you control in an element's lifespan.

Already own an older DROP?

You can't convert an older DROP into a DROP 2.0, but you can add some of the protection. The new retainers and the welded mesh support are built for the DROP 2.0 frame and don't fit the earlier cage. Several parts fit both versions, though:

  • Element spacers fit both versions. They're the simplest way to keep elements from touching at the bottom. Replacement spacers are available here.
  • The heat diverter fits both versions.
  • The 2023 HUUM upgrade kit (an element retainer plus a heat diverter) was designed for earlier DROP 7.5 and DROP 9 heaters.

The biggest step forward on an older unit costs nothing: follow the 100 / 200 / 400-hour stone schedule above, and make sure no element shows through the stones.

Warranty

Sauna Signature Radiant offers the same warranty terms as HUUM, the manufacturer. You'll find the current terms on HUUM's warranty page. The warranty assumes a correctly sized heater, suitable sauna stones and installation by a licensed electrician. Heating elements are a wear part over a heater's life, and genuine replacement elements are available from us.

HUUM DROP 2.0: frequently asked questions

What is the difference between the HUUM DROP and the DROP 2.0?

The DROP 2.0 keeps the same look, sizes and outputs, but redesigns the internals. It adds larger support rods, a factory-installed retainer and bottom spacers on every model, a cooler and better-sealed junction box, 14 AWG internal wiring with no splices, a 302 °F (150 °C) terminal strip, a heat diverter in every box, and a metal data plate with a batch number.

Did HUUM fix the DROP heating element problem?

DROP 2.0 targets the cause directly. Early element failures came mainly from elements touching each other after the stones shifted. Every DROP 2.0 now has three layers of element support (rods, retainer and spacers) installed at the factory. Correct stone laying and the 100 / 200 / 400-hour stone schedule still matter.

How do I know if my HUUM DROP is a 2.0?

Look at the front. DROP 2.0 has a larger stamped HUUM logo plate welded at all four corners, and a laser-etched metal data plate on the cage. Older units have a sticker label on the wall mount.

Which HUUM DROP size do I need?

At 240 V: the DROP 4.5 for 106–248 ft³, the DROP 6 for 177–318 ft³, the DROP 7.5 for 248–389 ft³ and the DROP 9 for 283–460 ft³. Add 3.3 ft³ for each square foot of uninsulated glass, brick, tile or concrete wall.

Does the HUUM DROP work on 208 V?

Yes, at reduced output: 3.4 kW (DROP 4.5), 4.5 kW (DROP 6), 5.6 kW (DROP 7.5) and 6.75 kW (DROP 9). Room sizes shrink accordingly.

How many sauna stones does the HUUM DROP need?

About 121 lb (55 kg) of natural sauna stones, 2–4 in (5–10 cm) in size. With the stones, the heater weighs about 143 lb (65 kg).

Do I put stones between the elements?

On the DROP 4.5 and DROP 6, yes, all the way to the bottom. On the DROP 7.5 and DROP 9, no: never place stones beneath the welded mesh support or between the elements.

How often should I change the stones in a HUUM DROP?

Inspect them every 100 hours of use (or at least once a year), rearrange them and replace cracked stones at 200 hours, and replace them all at 400 hours.

Can the HUUM DROP be installed in a sauna bench?

Yes. It can be partly recessed into a bench or floor, as long as at least 14¾ in (375 mm) stands above the surface. The DROP Embedding Flange finishes the opening.

Does the HUUM DROP need a separate controller?

Yes. The DROP has no built-in controls and needs a certified sauna heater controller, such as HUUM's UKU.

Choosing your DROP 2.0

Not sure which size fits your room, or whether your sauna's electrical service can handle a 40 A or 50 A circuit? Our sauna advisors can size the heater, controller and stones for your space. They can also confirm which version you own if you're ordering parts for an older DROP. Email [email protected], call 844.807.3925, or book a 15-minute call.

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