The overall Which? test score is made up of the following star ratings, all determined by our rigorous lab tests.
How we test main oven preheating time
This rating is based on how quickly the oven heats up to 150°C and 180°C. An excellent oven takes less than five minutes to get to 150°C and only a minute or two longer to get to 180°C. The slowest ovens will keep you waiting twice the time.
How we test cleaning the oven
We see how easy it is to clean the oven using a sponge and hot soapy water. We measure the success of this cleaning approach and the amount of effort required to get the cooker properly clean. Some range cookers have catalytic liners which should help give good results with less effort.
How we test energy efficiency
We simulate roasting a 2kg chicken and record how much energy each cooker uses across one hour and 40 minutes.
How we test main oven accuracy
We measure how well the oven maintains the set temperatures of 150°C and 180°C. An excellent oven will remain within a few degrees of the temperature you set it at, while poor ovens deviate by more than 30°C - which could have serious consequences for your dinner.
How we test oven heat distribution
We judge how well the main oven distributes heat by preparing trays of shortbread and seeing how evenly they bake. The best ovens turn out golden, evenly baked shortbread across the whole tray. The worst burn the edges or corners before the rest is properly baked.
How we test oven supply of heat
We bake a large sponge cake and record how well it rises, what the texture is like and whether it browns evenly. This gives a good indication of how well the oven supplies heat over a period of time.
How we test grill performance
We completely cover the grill pan with crustless white bread and then record how much of it turns golden brown. The best grills manage more than 90% coverage, while the worst turn less than 40% of the bread into decent toast.
How we test hob performance
We test how powerful a hob is by recording how long it takes to heat up a big panful of water. But we also test its ability at the other end of the scale and see how gently it can simmer. Next, we measure how well the heating zone or burner spreads heat across the base of a pan which indicates how evenly it will fry. Finally, we see what happens when you turn off the hob - and whether your food keeps cooking even when the power's off.
How we test cleaning the hob
We see how easy it is to clean the hob and pan supports using a sponge and hot soapy water. We record the success of this cleaning approach and the amount of effort required to get the cooker properly clean.
