In order to get the Which? recommendation, hobs must excel at heating quickly and also be good at low-temperature simmering.
All hobs are sent to the Which? test lab and undergo a series of rigorous tests that answer the following questions:
To see how quick and efficient a hob is, we time how long it takes to heat a pan of water from room temperature to 90°C, and we also record how much energy it uses in the process. The best hobs take just four and a half minutes to heat 1.5 litres of water, while the worst take closer to 11 minutes to do the same job.
We heat a pan of rice pudding and then leave it to simmer to find out how well a hob can heat at low temperatures and to see how responsive the controls are. The best hobs are very easy to control and adjust, while the worst are harder to control and could leave some of your rice pudding burnt.
To see how well heat spreads across the base of a pan, we heat a frying pan to 200°C and then take a photo with a thermal imaging camera. This shows how far the heat has spread and identifies any cold spots. The best hobs will heat the base of the pan evenly, but the worst will leave some areas much cooler.
We use a panel of three experts at the Which? test lab to find out how easy each hob is to use. We assess how easy it is to use the controls, check how clear the markings are and see whether there’s enough space to use all cooking zones at the same time. And we listen out for any unusual or irritating noises.
To see how easy each hob is to clean, we heat cooking oil and allow it to splatter on the burners, and we also allow a pan of rice to boil over. We leave the messy hobs to dry overnight and then attempt to clean them with washing-up liquid and a sponge.
All of the tests described above contribute to the overall percentage score each hob achieves.
However, as we consider that certain tests are more important than others, we weight them differently. We think it's crucial that a hob performs well at heating, simmering and frying, so these account for a larger part of the test score. The score is broken down in the following way:
Induction hobs need to score 75% or more for us to recommend them as a Best Buy, electric ceramic hobs 70% and gas (including gas-on-glass) hobs 65%. We think that any hobs that score 45% or less should be avoided, so we highlight them as Don't Buys.