OTOH it's pretty rare that I have a load of 4.6kW in my flat at any given time. Event 1kW seems a lot as a constant load - that would require me to run the hoov

OTOH it's pretty rare that I have a load of 4.6kW in my flat at any given time. Event 1kW seems a lot as a constant load - that would require me to run the hoover, washing maschine or the stove at full power and I rarely do that for hours on end. I haven't run the numbers, but I would guesstimate that 18kWh of electric energy get me a days worth or even longer.