The Stiebel Eltron DEM 4 Set (product no. 236462) is a 4.4 kW mini instantaneous water heater occupying the mid-point in the DEM Set family, bridging the gap between the plug-in DEM 3 and the higher-output DEM 6. Like all DEM Set models it delivers hot water on demand to a single hand washbasin using full electronic closed-loop temperature control, with an outlet temperature sensor maintaining the set outlet temperature to within one degree — no cold-blending at the tap required. The DEM 4 Set requires a dedicated hardwired 20 A RCD-protected circuit and is equally suited to oversink and undersink mounting, compatible with both pressurised and non-pressurised taps. It is the preferred choice where the 3.5 kW DEM 3 Set provides insufficient thermal lift — for example in colder regions or locations with lower mains water temperatures — but where a full 25 A hardwired circuit for the DEM 6 is not available or practical.
4.4 kWRated Output
19.1 ARated Current
20 ACircuit Fuse
30–50 °CTemp. Range
IP25Protection Rating
1.70 kgWeight
Installer Notice — Hardwired Connection Required: The DEM 4 Set does not include a plug and must be permanently hardwired via a dedicated 20 A double-pole isolator with a minimum 3 mm contact separation, protected by a 20 A RCD circuit. Cable cross-section must be sized in accordance with BS 7671 for the installed run length and installation method. Installation must be carried out by a qualified electrician and comply with Part P of the Building Regulations.
Installer Notice — Water Resistivity: This appliance uses a bare wire heating element. The electrical resistivity of the cold-water supply must be ≥ 1000 Ω·cm (conductivity ≤ 1000 µS/cm) at inlet temperatures up to 25 °C, or ≥ 1300 Ω·cm (conductivity ≤ 770 µS/cm) above 25 °C. Verify local water quality before installation. Do not install on demineralised or reverse-osmosis water supplies without specialist advice.
Anti-Scalding Temperature Lock: The internal permanent temperature limit provides child-safe, fixed anti-scalding protection. If this limit requires adjustment it must be performed by a qualified contractor — it is not user-accessible. The user-adjustable range is 30–50 °C.
Model Selection — Washbasin Use Only: The DEM 4 Set is rated for single hand-washbasin supply only. It is not rated for shower use. If shower capability is required, select the DEM 6 Set (product no. 236463), which provides 5.7 kW and is shower-suitable at inlet temperatures above 20 °C.
The Sweet Spot in the DEM Set Range: The DEM 4 Set delivers 25% more thermal output than the DEM 3 Set while requiring a less demanding circuit than the DEM 6 Set's 25 A hardwired supply. It is the ideal choice for applications with a cold mains supply below 12 °C where the DEM 3's 3.5 kW is marginal, but where the installation cannot accommodate a 25 A dedicated circuit.
Key Features
Electronic Closed-Loop Temperature ControlA dedicated outlet temperature sensor feeds real-time data to onboard control electronics, adjusting heating output continuously so the water exits at exactly the set temperature. There is no need to blend cold water at the tap — every litre drawn is at the correct temperature, eliminating the energy waste and frustration of manual adjustment common with basic instantaneous heaters.
4.4 kW — Greater Thermal LiftWith 4.4 kW at 230 V, the DEM 4 Set provides a meaningful temperature rise improvement over the 3.5 kW DEM 3. At a typical UK mains cold-water temperature of 10 °C and a minimum switch-on flow of >1.8 l/min, the extra kilowatt translates directly into a warmer, more comfortable handwashing experience — particularly important during winter months when mains temperatures drop.
Bare Wire Heating ElementThe maintenance-free bare wire heating system transfers heat directly and instantly into the water stream, with no thermal mass to overcome — meaning hot water arrives immediately when the tap opens. The element is suitable for hard and soft water alike, with open-wound construction that resists the scale build-up that can reduce efficiency and lifespan in sheathed elements.
Anti-Scalding ProtectionTwo complementary safeguards work in tandem: automatic output matching reduces heating power proportionally if the inlet water temperature rises unexpectedly, keeping outlet temperature within safe limits; and a fixed internal temperature limit (set by a qualified contractor) provides a permanent backstop that the user cannot accidentally override.
PROFI-RAPID Installation SystemThe back panel doubles as a precision drill template, with elongated slots to tolerate imprecise drill holes — reducing installation time considerably. Two-point wall fixing secures the unit. The cover and internal assembly detach with a single hand movement, giving unrestricted access during commissioning and service. External metal G 3/8 A water fittings allow direct universal tap connection without additional adaptors.
Oversink and Undersink in One UnitRotating the appliance 180° reconfigures it between oversink and undersink orientations without component changes. Water connections and cable routing are designed to suit either position, giving full flexibility to work around existing pipework, tile layouts, or under-sink cabinetry.
Pressurised and Non-Pressurised Tap CompatibilityAn integral variable flow-rate limiter and special aerator are included to ensure consistent performance with both open-outlet non-pressurised taps and standard pressurised taps. The aerator delivers an optimised flow pattern at the spout across the full range of mains supply pressures.
LED Diagnostic Traffic LightA built-in three-LED diagnostic indicator provides at-a-glance fault analysis during commissioning and service visits, enabling rapid identification of electrical, water-flow, and control faults without specialist diagnostic tools.
Point-of-Use EfficiencyBy heating water directly at the draw-off point and only when the tap is open, the DEM 4 Set eliminates the standing heat loss and dead-leg pipe-run waste inherent in cylinder-fed or central instantaneous systems. Energy is consumed only for the water actually used, making it highly efficient in intermittent or low-frequency-use applications such as staff cloakrooms, school washrooms, and commercial premises.
Technical Specification
| Identification |
|---|
| Product Number |
236462 |
| Model |
DEM 4 Set |
| Electrical |
|---|
| Rated Voltage |
230 V (1/N/PE) |
| Rated Output at 230 V |
4.4 kW |
| Rated Output at 200 V |
3.3 kW |
| Rated Output at 220 V |
4.0 kW |
| Rated Output at 240 V |
4.8 kW |
| Rated Current at 230 V |
19.1 A |
| Rated Current at 200 V |
16.7 A |
| Rated Current at 220 V |
18.2 A |
| Rated Current at 240 V |
20.0 A |
| Circuit Fuse (all voltages) |
20 A |
| Frequency |
50 / 60 Hz |
| Connection |
1/N/PE — hardwired; 20 A DP isolator required; cable to BS 7671 |
| Water |
|---|
| Water Connection |
G 3/8 A (external metal fittings) |
| Switch-On Flow Rate |
> 1.8 l/min |
| Water Resistivity ρ₁₅ ≥ (inlet ≤ 25 °C) |
1000 Ω·cm (conductivity ≤ 1000 µS/cm) |
| Water Resistivity ρ₁₅ ≥ (inlet > 25 °C) |
1300 Ω·cm (conductivity ≤ 770 µS/cm) |
| Performance |
|---|
| Outlet Temperature Range |
30–50 °C (user-adjustable) |
| Internal Anti-Scalding Limit |
Fixed — qualified contractor only |
| Control Method |
Electronic closed-loop (outlet sensor) |
| Shower Suitability |
Not rated for shower use |
| Physical |
|---|
| Height |
143 mm |
| Width |
190 mm |
| Depth |
82 mm |
| Weight |
1.70 kg |
| Colour |
White |
| IP Rating |
IP25 (splash-proof) |
Frequently Asked Questions
Does the DEM 4 Set include a plug?
No. Unlike the DEM 3 Set, the DEM 4 Set must be permanently hardwired. It requires a dedicated 20 A double-pole isolator with a minimum 3 mm contact separation, fed by an RCD-protected circuit. Cable cross-section must be selected by the installing electrician in accordance with BS 7671 for the specific run length and installation method. Installation must comply with Part P of the Building Regulations.
How does the DEM 4 Set compare to the DEM 3 and DEM 6 models?
The DEM Set range covers three output levels: the DEM 3 Set is 3.5 kW (13 A plug, 16 A circuit), the DEM 4 Set is 4.4 kW (hardwired, 20 A circuit), and the DEM 6 Set is 5.7 kW (hardwired, 25 A circuit — and uniquely rated for shower use at inlet temperatures above 20 °C). All three share identical physical dimensions (143 × 190 × 82 mm) and the same PROFI-RAPID installation system. The DEM 4 is the best choice where the DEM 3 lacks thermal lift but a 25 A dedicated circuit is impractical.
Can the DEM 4 Set supply a shower?
No. The DEM 4 Set is rated for single hand-washbasin supply only. Shower capability is exclusive to the DEM 6 Set (236463), which provides 5.7 kW and is suitable for shower use at cold-water inlet temperatures above 20 °C. If shower use is required, select the DEM 6 Set and ensure a 25 A hardwired circuit is available.
Can it be installed above or below the basin?
Yes. The DEM 4 Set supports both oversink and undersink installation using the same unit. Rotating the appliance 180° changes the orientation. The PROFI-RAPID back panel acts as a drill template, with elongated slots to compensate for drill-hole inaccuracies, and external G 3/8 A water fittings accommodate either position without requiring separate hardware.
Does the DEM 4 Set work with non-pressurised (open outlet) taps?
Yes. The appliance is compatible with both pressurised taps and non-pressurised open-outlet taps. The included integral flow controller and special aerator optimise the flow pattern for both types, maintaining consistent outlet temperature across varying inlet pressures and tap designs.
Is the DEM 4 Set suitable for hard water areas?
Yes. The bare wire heating element is inherently resistant to scale and is approved for both hard and soft water areas. There is no anode rod or sacrificial component to inspect or replace. However, the minimum water resistivity specification must be satisfied (≥ 1000 Ω·cm at inlet temperatures ≤ 25 °C; ≥ 1300 Ω·cm at inlet temperatures above 25 °C) — always verify the local mains water supply conductivity before installation.
What routine maintenance does the DEM 4 Set need?
Maintenance requirements are minimal. The bare wire element is entirely maintenance-free. The built-in inlet strainer should be inspected and cleaned periodically — particularly at first commissioning and following any work on the cold-water supply. If the appliance is drained or isolated from power for an extended period, it must be properly re-vented before power is restored to protect the heating element. No annual Gas Safe or G3 inspection is required.
