Anyone use a SAVAPLUG?

[Thurston Garden]

I've started saving hot water from the kettle: my kettle needs a minimum of two cups water - but being on my own, I often only make one cup of coffee. The rest goes into a flask. If I want another cuppa within a fairly short time, it's still hot enough; if it has cooled down too much, it'll go back into the kettle (with a top-up of cold) and will still save a bit of energy, as the kettle now comes to the boil quicker. A bit fiddly, I admit, but it works.

I have a metal insulated cup similar to this - it's pretty big so I only fill it once in the morning with coffee and once in the afternoon with tea. Keeps hot for hours! Kettle only has to go on twice.