-
According to the quooker website the unit costs 3p a day to run on standby it costs just over 2p to boil a litre of water in a kettle (I don't think these prices take into account current energy prices).
Taken from this which article
To be honest the most interesting thing about quooker is the life story of the guy who invented them. A dutch guy called Henri Peteri who, with his brother, fled the nazi invasion of the Netherlands in kayak, taking 56 hours to paddle to the UK across the North Sea.
It is basically a very high spec thermos flask with a heating element in it so the power draw is fairly small. It's not like keeping a pan on the boil more, like a trickle charger topping up a full battery.