Lab – Focus on the eco cooking method of built-in ovens

Still uncommon a few years ago, eco mode is now available on almost all built-in ovens on the market. As its name suggests, this feature allows, in theory, to save energy when cooking without impacting the results. But to achieve such performance, it is of course necessary to make some concessions, which ordinary cooks can hardly appreciate since they do not have the measurement tools that we use in our laboratory, including the famous temperature recording grid.

Thanks to it (and its slightly less sophisticated ancestor), we can record, to the nearest tenth of a degree, the exact temperature at eight points in the oven cavity which passes through our hands, once per second for a period of time. hour. For greater clarity, the 28,800 measurement points (8 x 3600) that we carry out are translated into a graph, which allows us to know precisely how the temperatures fluctuate in the enclosure.

Apart from the tests that we carry out in pulsed heat mode and in natural convection mode, we also focus on eco mode, mainly to measure its energy needs, but also to check how it manages temperatures.

And since the appearance of the built-in oven category on the site, we have seen more than sixty references from all brands and at all prices. This colossal database (yes, let’s give ourselves a little ointment) allows us to affirm that while energy savings are generally there, cooking performance, on the other hand, is very often very disappointing.

We notice that manufacturers use multiple methods to try to scrounge up a few kWh. At this point it is very important to keep in mind that we are setting the temperature to 200°C.

A common tip is to raise the temperature very slowly. This is the case at Samsung in particular.

We can clearly see that the heat increases very gradually and that even after an hour of heating, 200°C is not reached. By pushing the experiment a little, it is however very likely that the programmed heat corresponds to that of the speaker.

Another way of doing things, relatively similar but a little trickier, is to stick to a temperature in the muffle much lower than that programmed by the cook, despite what the oven display indicates.

The temperature rises well up to 200°C, but quickly drops below 150°C and stabilizes there, quite remarkably.

Finally (but other solutions probably exist on other built-in ovens), some manufacturers use heating in stages; the resistances operate at full capacity for a given period of time, stabilize the temperature for a few minutes then stop heating before starting this cycle again.

Once again, by prolonging the cooking, we would find the same curve profile repeating itself ad vitam aerternam.

In the kitchen, all these unsuitable, fluctuating or incorrect temperatures will inevitably lead to the failed cooking of dishes that require even a little accuracy in this area. We therefore forget the eco mode when baking or making slightly demanding savory dishes. On the other hand, it can be entrusted with reheating a dish with sauce or cooking a preparation to share (such as lasagna, tian, moussaka, enchiladas) by adjusting the cooking time slightly.

What are the savings thus achieved?

It is very difficult to answer this question as the situations are so different. Taking into account only the ovens in our comparison, on average, cooking for 45 minutes requires 0.71 kWh in pulsed mode, 0.88 kWh in static heat mode and 0.58 kWh in eco mode. However, we must not forget that these averages hide significant disparities, since the differences in consumption between the different modes start at less than 0.01 kWh and can rise up to 0.28 kWh. But based on the biggest difference between a classic cooking mode and an eco mode, we save 0.07 euro cents; It’s up to everyone to judge whether this minimal sum justifies the jeers caused by the failure of a soufflé.