My daughter has cut her bills dramatically with such a simple method. Basically she uses the Residual Current Device/Fuse Box as she would use a light switch. When the lights are not needed, they are turned off at the fuse box. When the water is not needed, which is most of the time, it is turned off at the fuse box. A quick flick of the switch in the morning and by the time breakfast is done, the water will be hot enough for a quick shower. Then flick the switch off again. Tea and coffee are better anyway with cold water in the kettle or the coffee machine. Stove off all day except for a short period to cook dinner. Of course, if one lives in a house it would be a lot of bother, but in a unit, the fuse box is mostly in the kitchen.

So easy, and the savings are huge.