Ovens and Hobs
In 1893 the Chicago World Fair showcased a futuristic all-electric kitchen with an electric oven as the centrepiece. This was a little ahead of its time and it took a further thirty or forty years before electricity grids became sufficiently widespread and robust for the technology to be widely adopted. Thermo-Electrical Cooking Made Easy, was published in March 1907, and is world’s first book on how to cook electrically.
The first mass use devices used resistive heating coils to heat iron hotplates on which the pans were placed. By the 1970s these started to be replaced by glass-ceramic tops which heated up and cooled down more quickly and allowed one part of the surface to be hot without energy being wasted heating up a neighbouring area. They were also much easier to clean.
More recently induction cooking has escaped from commercial kitchens and is now widely used domestically. Induction cooking only heats the special cooking vessels, and is faster and much more energy efficient than either of its predecessor technologies. It is also markedly safer as the surface cools as soon as the cooking vessel is removed.
Electric ovens already had labels that displayed their energy efficiency on a visual scale (G to A, with A being the most efficient).
Since 1 January 2015 these labels have been in the format D to A+++. The annual calculated average energy use is shown in kWh (electricity units).
The label also shows:
- The usable volume (size) of the cavity (oven) in litres
- The energy consumption per cycle for the conventional oven setting (in kWh/cycle)
- The energy consumption per cycle for the forced air convection (fan) setting
Hobs are not covered by the label.
Gas ovens have similar labels but with two figures for the energy use pictures, one expressed as MJ/cycle and the other as kWh/cycle so that you can compare gas ovens with electric ovens as well as with other gas ovens.
Cooker hoods also have energy labels which were phased in. Initially their scale was in the G to A format but evolved over time to the D to A+++ designation
The hood labels also show G to A ratings for fluid dynamic efficiency, lighting efficiency and grease filtering efficiency
Plus the annual energy consumption (kWh/annum) and a noise value (dB)
The microwave oven was a by-product of radar research. In 1946, Percy L. Spencer, an engineer with the Raytheon Corporation in America, noticed that the chocolate bar in his pocket melted while he was working on a radar-related project. He then put an egg near the magnetron tube, and watched it get hotter as a result of its exposure to low-density microwave energy. Dr Spencer began to experiment with other foods, fashioning a metal box into which he fed microwave power – the first microwave oven.
By 1947 the first commercial microwave oven, called the ‘Radarange’ was on the market. At over 1.7m in height and a third of a ton in weight, the oven was enormous, and so was the retail price – a whopping US$5000. Over the years the units have become a fraction of this size and price and are a staple of the modern kitchen.
The UK Microwave Market
93% of UK households had a microwave oven in 2012 .
 ONS – Family spending in the UK: April 2017 to March 2018 – Table A45 – Percentage of households with durable goods – 1970 to 2018