Some like It HOT


The last decades have shown an overwhelming increase of electric glass cooking surfaces in our kitchens. Today, we can find two different heating technologies in the market: Radiant and Induction. For non-specialists, both technologies use glass ceramics, which is a normally dark flat glass-like surface with some drawings on it for pot placing and controls.

The difference between both technologies lies in the Radiant heating up the pots by radiation and the Induction heating it by an electromagnetic field generated below the glass-ceramic plate. None of the systems directly heat up the food (we leave that for microwave ovens), rather they both heat up the pot and these heats up the food inside of it. Part of the radiation of the first system also heats up the glass ceramic plate, which is why the heating surface of these elements is greater than in the Induction system. This hot surface also heats up the cooking pot, so it receives heat from two sources: radiation and conduction. Radiant technology also has another singularity, which is residual heat. As mentioned, these elements partly heat up the glass, and this and the whole heater takes its time to cool down once the system is switched off. Experienced users have learnt to use this residual heat to finish heating their cooked meals. This technology is compatible with all types of pots, be it clay, aluminium, stainless steel, or enamelled steel. All materials are heated up by radiation, and all with similar efficiency.

The Induction system is faster since it does not need to heat the whole system but only the pot. This difference in speed can be of several minutes during the heating process, but minimum once the system is hot. The cons of this system include the fact that it is not able to work directly with most of the pots on the market, forcing users to renew their pot stock at home. If the proper pot quality is not used, the efficiency and general performance of the system is compromised. In extreme cases, the use of a poor-quality pot can even generate a system failure that would require the intervention of the after-sales service. Noise can also be noticeable in these systems, especially when it becomes hot, and the power electronics need to cool down.

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In recent years, the European Commission has put a lot of effort into making our appliances increasingly more efficient. We are all familiar with the energy labels that can be seen on the products in shops, showing the already classic energy letters, with “A” being more efficient than “B” and this than “C” and so on. These letters intend to act as a simple language for consumers so that they don’t have to make complex calculations to compare the different brands, technologies, and energy measuring units. To make this differentiation, measurable differences are needed between technologies and brands, otherwise they would all have the same energy label. This is exactly what happens in domestic electric cooking hobs: the difference in efficiency between Induction Technology and Radiant Technology is so small that it is not possible to give them an energy label since all the hobs on the market would have the same, regardless of the technology, manufacturer, or model. Some studies show that the total energy needed to manufacture(1) an Induction Hob is greater than that needed to manufacture a Radiant Hob, since it requires much more resources to manufacture its complex electronics.
Besides the characteristics that we have already mentioned, there are others that differentiate both systems, including the limitation of use that Induction cooking hobs have for users of pacemakers and hearing aids, or the poorer performance of the Radiant technology under spillages due the higher working temperature of the glass. The Radiant hobs are cheaper than Induction ones, especially if we consider the potential need for new compatible pots in the case of Induction hobs. With Radiant Technology, very few electronics are used -and, in some cases, no electronics at all. It is normally more durable than Induction, which must be considered in the total cost of the system.
In summary, both electric cooking systems have pros and cons. I find diversity to be very interesting, and it can convert the process of buying an appliance into an enriching experience for consumers, allowing them to choose the appliance that better fits their needs and cooking habits. Information, rather than urban legends, is essential for this process and I hope that this article has been of help. Quoting Jack Lemmon in the closing scene of “Some like it Hot”, we could say that “nobody’s perfect”, it’s just about finding the right kitchen partner in each case.

(1) This concept is known as LCA and adds up all the energy used by a product, considering the manufacturing phase, transportation, and use (cooking at home) phase.