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Stiebel Eltron water heater buying guide

Updated: 17.10.2026

You may be replacing a cylinder, adding hot water to an outbuilding, or trying to serve a sink without extending the gas system. This Stiebel Eltron water heater buying guide starts with the outlet and the electrical supply, because those two facts eliminate unsuitable models faster than a price or a star rating. The four products in our [Stiebel Eltron water heater comparison](/hub/hot-water/stiebel-eltron-water-heater) are not interchangeable: three DCE units heat water as it flows, while the SNU 10 Plus (GB) stores 10 litres under one compatible sink. Peter F. checked the UK listings and the maker’s figures, not a lab. A qualifying purchase can earn a commission at no extra cost to you.

You may be replacing a cylinder, adding hot water to an outbuilding, or trying to serve a sink without extending the gas system.

Our top picks

Stiebel Eltron Stiebel Eltron SNU 10 Plus (GB)

Best overall

Stiebel Eltron Stiebel Eltron SNU 10 Plus (GB)
10.0/10about £160.68
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Stiebel Eltron Stiebel Eltron DCE-X 10/12 Premium

Rank 2

Stiebel Eltron Stiebel Eltron DCE-X 10/12 Premium
8.8/10about £412.86
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Stiebel Eltron Stiebel Eltron DCE-S 10/12 Plus

Preis-Tipp

Stiebel Eltron Stiebel Eltron DCE-S 10/12 Plus
7.6/10about £327.61
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On this page
  1. 1.Start with the outlet, not the stars
  2. 2.Check the supply before the price
  3. 3.Choose an instantaneous DCE or the open-vented SNU
  4. 4.Compare controls only after the circuit is viable
  5. 5.What prices and ratings cannot decide

Start with the outlet, not the stars

For one basin, the DCE-X 6/8 Premium is the sensible instantaneous start: a lower band than a 10/12, still on fixed high-current wiring. The SNU 10 Plus is the other one-outlet option, only with its open-vented tap and a finite store. A single shower can justify the DCE-X 10/12 Premium or the DCE-S 10/12 Plus. “Suitable for showers” is not a flow guarantee. At 220 V the manual gives the 10/12 about 5.1 or 6.2 litres a minute at a 28 K rise, and about 2.9 or 3.5 at a 50 K rise. The shower guide tests that claim. None of the four is a convincing bath filler: a 6/8 buyer reported a trickle.

Check the supply before the price

No DCE here belongs on a BS 1363 socket. They are permanently connected, with protective earthing and an all-pole isolator. A qualified contractor installs, commissions and selects the connected load. The 6/8 band uses 30 or 40 A protection, and the 10/12 band uses 50 or 60 A. At 230 V the published steps are about 6.6/8.7 kW and 11.0/13.1 kW. Ask an electrician about the consumer unit, cable route and spare capacity before you order. A new circuit is generally notifiable in England and Wales. Scotland and Northern Ireland use their own building-control rules. The manual also sets a minimum supply pressure of 1.8 bar and water resistivity around 1,100 Ω·cm at 15 °C.
Stiebel Eltron Stiebel Eltron SNU 10 Plus (GB)

Testsieger

Stiebel Eltron Stiebel Eltron SNU 10 Plus (GB)
10.0/10about £160.68
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Choose an instantaneous DCE or the open-vented SNU

A DCE holds about 0.277 litre. It heats while the tap is open, and flow is capped by the selected kilowatts and the temperature rise. A normal-pressure tap is possible. The SNU 10 Plus (GB) stores 10 litres, mounts vertically under one washbasin or kitchen sink, and must stay open vented through a matching non-pressurised tap. Cold mains displaces hot water, so “open vented” does not mean a loft tank. A standard mixer would close the expansion path. Its 2 kW load is much easier electrically. You then get a finite draw and a reheat: roughly 19 litres mixed to 40 °C from a full store. That choice is on instantaneous versus storage.

Compare controls only after the circuit is viable

Once a 10/12 circuit is viable, control separates the models. The DCE-X uses 4i: a lit display, two temperature memories and ECO flow settings. The DCE-S uses 3i and a rotary selector across 20–60 °C. It has no display, memories or ECO menu, and it is not in a lower electrical band. Both use 43, 50 or 55 °C limit steps, and a contractor must cap a shower at 55 °C or less. The DCE-X 6/8 pairs Premium controls with the lower load and was £344.99 when researched, above the £327.61 DCE-S 10/12.

What prices and ratings cannot decide

Researched amazon.co.uk prices were £160.68 for the SNU, £327.61 for the DCE-S 10/12, £344.99 for the DCE-X 6/8 and £412.86 for the DCE-X 10/12. They exclude installation, a circuit and any special tap, and they move. The DCE-X 10/12 was 4.4 from 116 reviews, and those reviews still disagreed about showers. The DCE-S was 3.8 from 11 ratings, and one text described a doorbell. The SNU was 5.0 from one rating with no review. Match the outlet, the supply and the tap first.

Common questions

Can a Stiebel Eltron DCE plug into a 13 A socket?
No. The DCE units here require permanent fixed wiring, protective earthing and suitable isolation. Depending on the selected model and load, the published protection is 30/40 A for the 6/8 or 50/60 A for the 10/12. A qualified electrician should confirm the circuit before you buy.
Is the 6/8 model only for a hand basin?
It is the safer starting point for one basin or modest kitchen-sink use. Some manufacturer wording includes a shower, but the manual’s heated-flow figures are limited and one Amazon reviewer reported a bath trickle. Do not choose it for a bath, and assess any shower against the actual temperature rise.
Does 4i control make more hot water than 3i?
No. The 4i DCE-X adds a display, two memory keys and ECO settings. It does not create extra heating output within the same load band. A DCE-X 10/12 and a DCE-S 10/12 should be judged on the same electrical and flow constraints before convenience features.
When is the SNU 10 Plus the right choice?
Choose it for one undersink basin or kitchen sink where a compatible open-vented tap is acceptable and a modest 2 kW load is preferable. Do not choose it for a normal mixer, several outlets or a shower. It stores 10 litres and must reheat after that hot water is used.
Who should confirm the consumer unit?
A qualified electrician should assess the consumer unit, protective devices, earthing, cable route and available capacity. The installer also selects and commissions the connected load. Do not order a 10/12 model on the assumption that an existing cooker or shower circuit can simply be shared.
Are the listed prices the installed cost?
No. They are researched amazon.co.uk product prices in GBP and do not include a dedicated circuit, consumer-unit work, plumbing alterations, a special SNU tap or labour. Obtain installation quotations before using the product-price difference to choose between models.

Related pages

Best Stiebel Eltron water heater

How to use a Stiebel Eltron water heater

Stiebel Eltron water heater

Stiebel Eltron water heater for one shower in the UK

Stiebel Eltron instant heater or a storage heater

Sources

Manufacturer pages, UK public sources and the amazon.co.uk listings in this comparison, retrieved on 17 October 2026.

  1. Stiebel Eltron DCE-X 10/12 Premium (retrieved 17 October 2026)
  2. Stiebel Eltron DCE-X instruction and installation manual (retrieved 17 October 2026)
  3. Stiebel Eltron DCE-S 10/12 Plus (retrieved 17 October 2026)
  4. Stiebel Eltron SNU 10 Plus (GB) technical data (retrieved 17 October 2026)
  5. Water Supply (Water Fittings) Regulations 1999, Schedule 2 (retrieved 17 October 2026)
  6. Approved Document G (England) (retrieved 17 October 2026)
  7. HSE: hot and cold water systems (retrieved 17 October 2026)
  8. IET: Part P in England and Wales (retrieved 17 October 2026)