Same brand, same 14 place settings, same 60 centimetres of width. One costs 683.57 euros and sits in class B, the other 968.57 and sits in class A. We opened the two EU fiches line by line: the cleaning index is the same number on both and the premium takes 24.7 years to pay back.
Two Siemens dishwashers, same brand, same 14 place settings, same 60 centimetres of width. One costs 683.57 euros, the other 968.57. That is exactly 285 euros apart, 41.7 per cent more, and anyone reading only the energy label finds a class B on one side and a class A on the other. Looks straightforward.
We at PortosEunostos downloaded the two official product fiches filed by BSH and laid them side by side, line by line. The result flips the reading: the washing efficiency index is the very same number on both. Those 285 euros are not buying you cleaner plates.
What you will find below
The two machines in one line
The Siemens SN23EI03ME is an iQ300 freestanding model, anti-fingerprint brushed steel, 84.5 x 60 x 60 cm. It stands on its own in the middle of the kitchen, and with the top removed (3 centimetres) it slides under a standard worktop.
The Siemens SN55ES12CE is an iQ500 semi-integrated model with a visible control panel, 81.5 x 59.8 x 57.3 cm, and it needs a niche of 815-875 x 600 x 550 mm. The body disappears into the cabinet, the panel stays out.
Two different installation types, not two quality levels: the same distinction we untangled for washing machines in our piece on built-in or freestanding.
Where they are identical, which is nearly everywhere
The values below come from the product fiches filed under Regulation (EU) 2019/2017, not from marketing copy.
| Parameter | SN23EI03ME | SN55ES12CE |
|---|---|---|
| Rated capacity | 14 place settings | 14 place settings |
| Cleaning efficiency index | 1.121 | 1.121 |
| Drying efficiency index | 1.061 | 1.061 |
| Water, eco programme | 9.0 litres | 9.0 litres |
| Airborne noise emissions | 42 dB(A), class B | 42 dB(A), class B |
| Repairability index | 9.3 | 9.4 |
| Minimum supplier warranty | 24 months | 24 months |
| Energy, eco programme | 0.645 kWh/cycle | 0.543 kWh/cycle |
| Energy class | B (EEI 37.9) | A (EEI 31.9) |
| Eco programme duration | 3 h 35 | 4 h 30 |
| Price on 12 October 2026 | 683.57 euros | 968.57 euros |
Cleaning, drying, water, noise and warranty: five lines out of five overlapping. Even the repairability index, the one that from 2027 will be printed on the energy label, is practically the same: 9.3 against 9.4.
The three real differences
Energy. 0.645 kWh per cycle against 0.543: the iQ500 uses 15.8 per cent less, and that is the whole jump from class B to class A. In litres of water, we repeat, nothing changes.
Time. The eco programme on the SN23EI03ME runs for 3 hours and 35 minutes, the one on the SN55ES12CE for 4 hours and 30. Fifty-five minutes longer, every single time. It is not a flaw, it is how energy gets saved: more time at a lower temperature. The same mechanism we explain in our guide on how much energy a dishwasher uses.
Equipment. Both have Home Connect, autoOpen dry, an iQdrive motor, aquaSensor, aquaStop, a third cutlery rack and a Rackmatic upper basket adjustable over 3 levels. The iQ500 adds touch controls, 8 programmes instead of 6 (Glass 40 °C and Silence 50 °C join the list), the glassZone area for stemware, emotionLight interior lighting, 8 folding spikes in the lower basket instead of 4 and steam protection for the cabinet.
The maths on those 285 euros
Let us do it with our own numbers, the ones we use across the whole site: 260 cycles a year, five a week, and the ARERA electricity tariff for the fourth quarter of 2026 at 0.4343 euros per kWh (we redid every calculation with this tariff in our article on what it costs to run your appliances).
SN23EI03ME: 167.7 kWh a year, 72.83 euros of electricity.
SN55ES12CE: 141.2 kWh a year, 61.31 euros of electricity.
Difference: 11.52 euros a year.
Divide 285 euros by 11.52 and you get 24.7 years. Over ten years of the machine's life, class A gives you back 115.20 euros of the 285 you paid up front: 169.80 are still missing. Put plainly, the premium never pays for itself through the electricity bill.
That does not mean the SN55ES12CE is not worth its money: it means you buy it for the integrated front, the touch controls and the glassZone, not for the energy. If the bill were the goal, it would matter far more to stop running the dishwasher half empty.
The noise line needs checking
One concrete warning. The catalogue sheet for the SN55ES12CE, at some retailers, reports 45 dBA. The EU product fiche filed by BSH and the Siemens technical sheet both say 42 dB(A), noise emission class B, exactly like the SN23EI03ME, and the iQ500 drops to 41 dB(A) in the Silence programme.
When two lines disagree, the manufacturer's official fiche wins, not the shop table. That holds for Siemens as it does for Bosch, which belong to the same BSH group and share platforms, as we verified in our Bosch or Siemens comparison.
Which of the two to buy
The SN23EI03ME makes sense if your kitchen is already built and you have no niche for a built-in unit, if you are furnishing a rented flat and the machine will have to move with you, or if you simply prefer to spend 285 euros less for the same washing result. With the top removed it still goes under the worktop.
The SN55ES12CE makes sense if you are fitting a new kitchen and the 55 cm deep niche is already there, if you want the dishwasher out of sight, if you often wash stemware (glassZone is not marketing: those are dedicated jets) and if the extra 55 minutes do not bother you because you run it overnight.
If you have not even settled on the width yet, start from our piece on 45 or 60 cm dishwashers and come back here.
PortosEunostos tips
Measure the niche before you fall for the model. The SN55ES12CE asks for 550 mm of depth and a height adjustable between 815 and 875 mm: if the cabinet is not there, the built-in option is not an option.
Look at the cleaning index, not just the energy class. The class measures kWh, not how well it washes. Here it is 1.121 on both.
Turn the class difference into euros a year before you pay for it. Eleven and a half euros a year do not justify 285 euros up front.
Check the seller, not only the price. On both these models the stated availability is 15 to 20 working days: check delivery times, carriage to the floor, old appliance collection, returns and warranty terms.
Ask whether installation is included. On a built-in unit, plumbing it in and fitting the front panel is worth more than on a freestanding one.
In two lines
The two Siemens machines wash and dry the same way, use the same water and make the same noise. The iQ500 costs 285 euros more and is worth it only if you need the built-in format: class A on its own takes almost twenty-five years to pay back.
Current prices and availability are on the SN23EI03ME and SN55ES12CE pages at OpportunityCommerce, whose dishwasher category holds 261 products. To put these two next to other brands, go through SniffaPrezzi, bearing in mind that the Siemens units in stock there are all fully integrated, which is a third installation family again.
Sources
SN23EI03ME product fiche, Reg. (EU) 2019/2017, version of 11 December 2025.
SN55ES12CE product fiche, Reg. (EU) 2019/2017, version of 17 January 2025.
Siemens technical sheets for both models, product pages on siemens-home.bsh-group.com; sibling brand site at bosch-home.com.
Prices and availability recorded on 12 October 2026 on OpportunityCommerce; ARERA electricity tariff for the fourth quarter of 2026, 0.4343 euros per kWh.
