Monitoring your own power isn’t so simple | Letters

A few years ago our electricity supplier provided us with a simple device to monitor our use. It tells us how much power we are using and what it is costing, by day and by month. Of course, there is always a small trickle because of various clocks around the house, the fridge, etc. But when we switch the kettle on, it suddenly tells us we are spending £375 a month (of course it is only for five minutes). This device provides us with a conversation piece and not much else. We already send o